Aristotle (384-322 B.C.) was an ancient Greek philosopher and polymath. Along with Plato, whose disciple he was at the Academy, he is one of the most influential thinkers that the Western world has known. He is also one of the few to have tackled almost all the fields of knowledge of his time: biology, physics, metaphysics, logic, poetics, politics, rhetoric, ethics and, occasionally, economics. For Aristotle, philosophy, originally “love of wisdom”, is understood in a broader sense as the search for knowledge for its own sake, questioning the world and the science of sciences.

For him, science comprises three main areas: theoretical science, practical science and productive or poetic (applied) science. Theoretical science constitutes the best use that man can make of his free time. It is composed of the “first philosophy” or metaphysics, mathematics and physics, also called natural philosophy. The practical science turned towards action (praxis) is the domain of politics and ethics. The productive science covers the field of technique and the production of something external to man. It includes agriculture, but also poetry, rhetoric and, in general, everything that is made by man. Logic, on the other hand, is not considered by Aristotle as a science, but as the instrument that allows the sciences to progress. Set out in a work entitled Organon, it is based on two central concepts: the syllogism, which will strongly influence Scholasticism, and the categories.

Nature (Physis) holds an important place in Aristotle”s philosophy. According to him, natural matter possesses in itself a principle of motion (en telos echeïn). Consequently, physics is devoted to the study of natural movements caused by the proper principles of matter. Beyond that, for its metaphysics, the god of the philosophers is the first mover, the one who sets the world in motion without being himself moved. In the same way, all the living have a soul, but this one has various functions. The plants have only a soul animated of a vegetative function, that of the animals possesses at the same time a vegetative and sensitive function, that of the men is endowed in addition with an intellectual function.

Ethical virtue, according to Aristotle, is a balance between two excesses. Thus, a courageous man must be neither reckless nor cowardly. It follows that Aristotelian ethics is very much marked by the notions of measure and phronêsis (in French wisdom). His ethics, just like his politics and economics, is turned towards the search for the Good. Aristotle, in this field, deeply influenced the thinkers of the following generations. In connection with his naturalism, the Stagirite considers the city as a natural entity which cannot last without justice and friendship (philia).

After his death, his thought was forgotten for several centuries. It was not until the end of Antiquity that he came back to the forefront. Since the end of the Roman Empire and until his rediscovery in the 12th century, the West, unlike the Byzantine Empire and the Muslim world, had only limited access to his work. From the time of his rediscovery, Aristotle”s thought strongly influenced Western philosophy and theology for the next four to five centuries, not without creating tensions with the thought of Augustine of Hippo. Associated with the development of universities, which began in the 12th century, it had a profound effect on scholasticism and, through the work of Thomas Aquinas, on Catholic Christianity.

In the 17th century, the breakthrough of scientific astronomy with Galileo and Newton discredited geocentrism. This led to a profound retreat from Aristotelian thought in everything related to science. His logic, the instrument of Aristotelian science, was also criticized at the same time by Francis Bacon. This criticism continued in the 19th and 20th centuries when Frege, Russell and Dewey reworked in depth and generalized the syllogistic. In the XIXth century, his philosophy has been revived. It is studied and commented by Schelling and Ravaisson, among others, then by Heidegger and, after him, by Leo Strauss and Hannah Arendt, two philosophers considered by Kelvin Knight as “practical” neo-Aristotelians. More than 2,300 years after his death, his thought is still studied and commented upon by Western philosophy.

The French name Aristotle derives from the Greek name Aristoteles (in ancient Greek: Ἀριστοτέλης .

It is composed of aristos “the best” and telos “completion, accomplishment, realization”.

Aristotle”s life is known only in outline. His work contains very few biographical details and few testimonies from his contemporaries have come down to us. His doxographers (among others, Dionysius of Halicarnassus and Diogenes Laerece) are a few centuries older than him. He was the tutor of Alexander the Great to whom he transmitted the critical and philosophical spirit as well as the feeling of belonging to Hellenism. According to his biographers, notably Diogenes Laërce, Aristotle had a certain sense of humor and either stuttered or had a hair on his tongue.

Years of youth

Aristotle was born in 384 B.C., in the city of Chalkidiki located on the Strymonic Gulf in Greece, hence his nickname of “Stagirite”. His father, Nicomachus, belonged to the corporation of the Asclepiades. He is the doctor and the friend of king Amyntas III of Macedonia. His mother, Pheastias, a midwife, came from Chalcis on the island of Evia. The family of Aristotle claims to descend from Machaon. Fatherless at eleven, he was raised by his brother-in-law, Proxenes of Atarna, in Mysia. It is at this time that he befriended Hermias of Atarnée, future tyrant of Mysia.

Around 367, at the age of seventeen, he was admitted to Plato”s Academy. Plato, having noticed his keen intelligence, gave him the right to teach rhetoric as a tutor. He becomes anagnostic of Plato, who calls him “the reader” or “the intelligence of the school”, in ancient Greek “Nοῦς τῆς διατριβῆς”. This will not prevent Aristotle from rejecting Plato”s theory of Ideas, justifying himself thus: “Friend of Plato, but even more of the truth”. Trained and deeply influenced by the Platonists, he adds: “They are friends who introduced the doctrine of Ideas. Truth and friendship are both dear to us, but it is our sacred duty to give preference to truth”.Aristotle probably participated in the Eleusinian Mysteries.

Preceptor of Alexander the Great

During the period when he was teaching at the Academy, Aristotle followed local political life, but was unable to participate in it because of his status as a metacarpal. When Plato died around 348-347 BC, his nephew Speusippe succeeded him as scholar. Aristotle, dejected, left for Atarna with his fellow student Xenocrates, departure perhaps also related to the growing hostility towards the Macedonians. Shortly before, king Philip II took part in massacres in Olynthe, a city friendly to the Athenians, and made raze Stagira, whose population was sold with the auction.

In Atarnea in Troades, on the coast of Anatolia, Aristotle joined Hermias of Atarnea, a childhood friend and tyrant of this city. When Macedonia and Athens made peace in 346, Aristotle settled in the small port of Assos with Xenocrates and two other Platonic philosophers, Erastos and Coriscos. He opened a school of philosophy inspired by the Academy where his listeners were Callisthenes, Theophrastus from nearby Lesbos, as well as Nelaeus, son of Coriscos. He continued his biological research and began to observe the marine fauna. After three years, he goes to Mytilene, in the nearby island of Lesbos, where he opens a new school.

In 343, at the request of Philip II, he became the tutor of the crown prince, the future Alexander the Great, then thirteen years old. The choice of Aristotle by Philip must have been easily imposed, partly because of the relations of friendship which unite since their young age the king of Macédonia and the philosopher. Aristotle, exceptional encyclopedist as of this time, is also preferred with the old Isocrates, with its two disciples, Isocrates of Apollonia and Théopompe, as well as with Speusippe. He teaches Alexander the letters and undoubtedly the policy, during two or three years, with the Nympheum of Miéza. Alexander receives the lessons in company of his future companions in arms: Héphestion, Ptolémée, Perdiccas, Eumène, Séleucos, Philotas and Callisthène. When Alexander became regent at the age of fifteen, Aristotle ceased to be his tutor, but remained at court for the next five years. According to some sources, Alexander provided him with animals from his hunts and expeditions to study, which allowed him to accumulate the enormous amount of documentation that his zoological works show.

Around 341, he takes in and marries Pythias, niece and adopted daughter of Hermias, refugee in Pella, who gives him a daughter, also named Pythias. Widowed in 338, he takes for second wife a woman from Stagira, Herpyllis, from whom he has a son whom he names Nicomachus. The Nicomachean Ethics, which deals with virtue and wisdom, is neither addressed to Aristotle”s father, long dead, nor to his son who was not yet born at the time of its writing, but mentions Nicomachean son as the editor of the Nicomachean Ethics, helped by Theophrastus or by Eudemus.

Aristotle returns to Athens in 335, whereas the city is spared by Alexander although it revolted against the Macedonian hegemony in company of Thebes.

Lycée Foundation

Aristotle founded his third school, the Lyceum, around 335 BC, on a rented piece of land, because being a metacarpal, he had no right to own property. The Lyceum is located on a place of promenade (peripatos) where the master and his disciples stroll during their leisure time. The Aristotelians are thus “those who walk near the Lyceum” (Lukeioi Peripatêtikoi, Λύκειοι Περιπατητικοί) hence the name peripatetic school that is sometimes used to refer to Aristotelianism. The Lyceum includes a library, a museum or Mouseîon, as well as lecture rooms and equipment for study and research.

Aristotle gave two types of courses: the morning course, “acroamatic” or “esoteric”, was reserved for advanced disciples; the afternoon course, “exoteric”, was open to all. He lived in the woods of Mount Lycabetta.

His third and last great period of production was in the Lyceum (335-323) during which he probably wrote book VIII of the Metaphysics, the Small Treatises of Natural History, the Ethics to Eudemus, the other part of the Nicomachean Ethics (books IV, V, VI), the Constitution of Athens, the Economics.

Last years

In 327 B.C., Alexander had Callisthenes, Aristotle”s nephew, put in prison because he refused to bow down to him in the Persian fashion and was allegedly involved in the conspiracy of Hermolaos and the pages. Callisthenes dies during his captivity in Bactria. The death and the dishonor inflicted on his nephew lead Aristotle to move away from his former pupil, including on the level of the political thought, as tends to prove it one of his last writings entitled Alexander or of the Colonies.

After the death of Alexander the Great in June 323, threatened by the anti-Macedonian agitation brought to its height in Athens by the rebellion against Antipater, Aristotle considered it prudent to flee Athens, a flight all the more justified since Eurymedon, hierophant at Eleusis, brought against him an absurd accusation of impiety, reproaching him for having composed a Hymn to the virtue of Hermias of Atarna, a kind of poem reserved only for the worship of gods. Determined not to let the Athenians commit a “new crime against philosophy” – the first one being the death sentence of Socrates -, Aristotle took refuge with his second wife, Herpyllis, and his children, Pythias and Nicomachus, in the island of Euboea, in Chalcis where his mother had inherited an estate. It is there that he dies, aged 62 years, carried away undoubtedly by the disease of stomach from which he suffers since a long time. In his will, he made provisions for the emancipation of his slaves and thought of ensuring the future of all his relatives. His body is transferred to Stagire.

Theophrastus, his fellow student and friend, succeeded him as head of the Lyceum. At the time of Theophrastus and his successor, Straton of Lampsacha, the Lyceum declined until the fall of Athens in 86 BC. The school was refounded in the first century BC by Andronicos of Rhodes and enjoyed a strong influence until the Goths and Heruli sacked Athens in 267 AD.

Physical aspect

Aristotle is short, stocky, with spindly legs and small sunken eyes. His dress is flashy and he does not hesitate to wear jewels. The ancient sources describe Aristotle with a bald head (Anonymous Life), small eyes (Diogenes Laërce, V, 1) and short hair and beard (the full-length statuary type is attested (a statue of the Spada palace is wrongly identified with the philosopher).

Aristotle attached great importance to commemorative portraits, which can be seen in his will and that of Theophrastus and in the testimony of Pliny (XXXV, 106) who attests to a painted portrait of the Stagirite”s mother. 18 copies of the bust of Aristotle are preserved, as well as glass pastes with the face in profile. This portrait is very close to the one of Euripides, whom Aristotle admired a lot, composed around 330-320 BC. The attribution of its creation to Lysippus is not certain.

Appearances and credible opinions (endoxa)

Aristotle”s approach is the opposite of Descartes”. While the French philosopher begins his philosophical reflection with a methodological doubt, Aristotle argues on the contrary that our capacities of perception and cognition bring us into contact with the characteristics and divisions of the world, which therefore does not require a constant skepticism. For Aristotle, appearances (phainomena in Greek), the strange things we perceive, lead to thinking about our place in the universe and to philosophizing. Once the thought is awakened, he recommends to look for the opinions of serious people (endoxa comes from endoxos, a Greek word for a notable man of high reputation). It is not a question of taking these credible opinions as truths, but of testing their capacity to account for reality.

Philosophy and science

In the Protrepticus, an early work, Aristotle states that “human life implies the need to be a philosopher, that is to say, to love (philein) and to seek science, or more precisely wisdom (sophia)”. At that time, philosophy is, for him, the desire to know. Philosophy seeks in fine the good of human beings. Philosophy thinks the totality. Science or, to use Aristotle”s word, episteme, deals with particular fields of knowledge (physics, mathematics, biology etc.). Theoretical philosophy is therefore primary in relation to praxis, a term often translated as “practical science” and from which politics comes: “Aristotle distinguishes between the happiness that man can find in political life, in active life, and philosophical happiness, which corresponds to theory, that is to say, to a kind of life that is devoted entirely to the activity of the mind. The political and practical happiness is happiness in the eyes of Aristotle only in a secondary way “.

The modern distinction between philosophy and science dates from the end of the 18th century, and is therefore largely posterior to Aristotle. It is also later than the article “philosophy” in Diderot and d”Alembert”s Encyclopédie.

Epistèmè (science) and technè (art, techniques)

Aristotle distinguishes five intellectual virtues: technè, epistèmè, phronésis (prudence), sophia (wisdom) and noûs (intelligence). Technè is often translated as art or technique, while episteme is translated as knowledge or science. However, episteme does not correspond to the notion of modern science because it does not include experimentation. While episteme is the science of eternal truths, technè (art, technique) is devoted to the contingent and deals with what man creates. Medicine is both episteme, because it studies human health, and technè, because it is necessary to cure a patient, to produce health. While episteme can be learned in a school, technè comes from practice and habit.

Science uses demonstration as an instrument of research. To demonstrate is to show the internal necessity that governs things, it is at the same time to establish a truth by a syllogism based on certain premises. Demonstrative science “starts from universal definitions to arrive at equally universal conclusions”. However, in practice, the mode of demonstration of the different sciences differs according to the specificity of their object.

The ternary division of the sciences (theoretical, practical and productive) does not include logic because its task is to formulate “the principles of correct argumentation that all fields of research have in common”. Logic aims to establish at a high level of abstraction the norms of inference (cause and effect relationships) that must be followed by someone seeking truth, and to avoid spurious inferences. It is developed in a body of work known since the Middle Ages as the Organon (Greek for instrument). What is called “productive science” is technè and production (practical science is praxis (action) and epistèmè (science) in that it also seeks stable inferences within a science.

Speculative or contemplative science

Speculative or theoretical science (θεωρία, “contemplation”) is disinterested, it constitutes the end in itself of the human soul and the completion of thought. It constitutes the best use that man can make of his free time (skholè), during which, detached from his material concerns, he can devote himself to the disinterested contemplation of the true. This is the reason why some Aristotle scholars, like Fred Miller, prefer to speak of contemplative rather than theoretical sciences. There are as many divisions of theoretical science as there are objects of study, i.e. different fields of reality (genera, species, etc.). Aristotle distinguishes between “first philosophy” – the future metaphysics, which has as its object of study the totality of what is – mathematics, which deals with numbers, i.e. quantities in general, taken from reality by abstraction, and physics or natural philosophy. Physics first of all shows a will to understand the universe as a whole. It aims more at solving conceptual enigmas than at carrying out empirical research. It also seeks causes in general as well as the first and last cause of any particular movement. Aristotle”s natural philosophy is not limited to physics proper. It includes biology, botany, astronomy and perhaps psychology.

Practical science (praxis)

Action (praxis, in ancient Greek πρᾶξις), as opposed to production (poesis), is, according to Aristotle, the activity whose end is immanent to the subject of the activity (the agent), as opposed to production, the activity whose end (the object produced) is external to the subject of the activity. The practical sciences concern human action, the choices to be made. They include politics and ethics. The practical science (praxis) is a matter of practical reason (phronesis)

Productive or Poetic Science (τέχνη)

It is the know-how or the technique, which consists in a disposition acquired by use, having for goal the production of an object which does not have its principle in itself, but in the agent who produces it (as opposed to a natural production). The technè being at the service of a production, it is in the domain of utility and pleasure, it always aims at the particular and the singular. Agriculture, boat building, medicine, music, theater, dance, rhetoric are all productive sciences.

Science in Aristotle and Plato : hylémorphism versus idealism

According to Aristotle, Plato conceives “the essence or idea (εἶδος, eïdos) as a being existing in itself, quite independently of sensible reality” so that science must go beyond the sensible to reach “intelligibles, universal, immutable and existing in themselves”. This way of seeing presents, according to him, two major disadvantages: it complicates the problem by creating intelligible beings and it leads to think the ideas, the universal, as independent of the sensible which, according to him, moves us away from the knowledge of the real.

For Aristotle, essence or form (eïdos morphè) can only exist embodied in matter (ὕλη, hulé). This leads him to elaborate “the thesis known as hylémorphism, which consists in thinking the immanence, the necessary conjunction, in any existing reality, of matter (hulè) and form (morphè) that models it”.

But, in doing so, he finds himself confronted with the problem of the universal. Indeed, for Plato, this question does not arise since the universal belongs to the domain of ideas. For Aristotle, the universal consists rather in an intuition of form or essence and in the fact of positing a statement, such as the definition of a man as a “political animal”.


The Organon is a collection of treatises on how to do right thinking. The title of the book, “organon”, which means “working instrument”, is a statement against the Stoics for whom logic is a part of philosophy.

Book I, called Categories, is devoted to the definition of words and terms. Book II, dedicated to propositions, is named in Greek Περὶ ἑρμηνείας Peri Hermeneias, i.e., “Of Interpretation”. Scholars generally refer to it by its Latin name De Interpretatione. Book III, called the First Analytics, deals with the syllogism in general. Book IV, called the Second Analytics, is devoted to syllogisms whose results are the fruit of necessity (ex anankês sumbanein), i.e. are the logical consequences of the premise (protasis). Book V, called Topics, is dedicated to the rules of discussion and to syllogisms whose premises are probable (dialectical reasoning from generally accepted opinions). Book VI, called Sophistic Refutations, is considered as a final section or appendix of book V. In Book II De Interpretatione, some chapters are particularly important, such as chapter 7 from which the logical square is derived as well as chapter 11 which is the origin of modal logic.

Investigation, demonstration and syllogism

In the First Analytics, Aristotle seeks to define a method for a scientific understanding of the world. For him, the goal of research or investigation is to arrive at “a hierarchically organized system of concepts and propositions, based on knowledge of the essential nature of the object of study and on certain other necessary first principles. For Aristotle, “analytical science (analytiké episteme) teaches us to know and state causes by means of well-constructed demonstration”. The goal is to reach universal truths of the subject in itself by starting from its nature. In the Second Analytics, he discusses how to proceed to reach these truths. To do so, one must first know the fact, then the reason why this fact exists, then, the consequences of the fact, and the characteristics of the fact.

Aristotelian demonstration is based on the syllogism, which he defines as “a discourse in which, certain things being stated, something other than these data necessarily follows by the mere fact of these data”.

The syllogism is based on two premises, a major and a minor, from which a necessary conclusion can be drawn. Example:

A scientific syllogism must be able to identify the cause of a phenomenon, its why. This mode of reasoning raises the question of regression to infinity, which occurs, for example, when a child asks us why something works like that, and once the answer is given, he asks us why the premise of our answer was given. For Aristotle, it is possible to stop this regression to infinity by holding certain facts coming from experience (induction) or coming from an intuition as certain enough to serve as a basis for scientific reasoning. However, for him, the necessity of such axioms must be explained to those who would contest them.

Definitions and categories

A definition (in ancient Greek ὅρος, ὁρισμός horos, horismos) is for Aristotle, “an account which means that what is, is for something (it states the proper essence of the thing under consideration. By this Aristotle means that a definition is not purely verbal, but translates the deep being of a thing, which the Latins translated by the word essentia (essence).

He then asks himself one of the central questions of Aristotelian metaphysics, what is an essence? For him, only species (eidos) have essences. The essence is thus not proper to an individual but to a species which he defines by its kind (genos) and its difference (diaphora). Example “a human being is an animal (genus) which has the capacity to reason (difference)”.

The problem of definition raises the problem of the concept of essential predicate. A predicate is a true statement, as in the sentence “Bucephalus is black”, which presents a simple predicate. For a predicate to be essential, it is not enough for it to be true, it must also provide a precision. This is the case when we declare that Bucephalus is a horse. For Aristotle, “A definition of X must not only be an essential predicate but must also be a predicate only for X”.

The word category derives from the Greek katêgoria which means predicate or attribute. In Aristotle”s work, the list of the ten categories is present in Topics I, 9, 103 b 20-25 and in Categories 4,1 b 25 – 2 a 4. The ten categories can be interpreted in three different ways: as kinds of predicates; as a classification of predicates; as kinds of entities.

Dialectic, Aristotle versus Plato

For Plato, the word “dialectic” has two meanings. First, it is “the art of proceeding by questions and answers” to arrive at the truth. In this sense, it is at the center of the philosophical method as shown by the numerous Platonic dialogues. Dialectic is also, for Plato, “the art of rigorously defining a notion through a method of division, or dichotomous method”. For Aristotle, on the contrary, dialectic is not very scientific, since his argumentation is only plausible. Moreover, he holds that the divisions of the thing studied are subjective and can induce what one wants to demonstrate. Nevertheless, for him, dialectic is useful to test some credible opinions (endoxa), to open the way to first principles or to confront other thinkers. Generally speaking, the Stagirite assigns three functions to dialectic: the formation of human beings, conversation and “science conducted in a philosophical way (pros tas kata philosophian epistêmas)”.

Aristotle and Plato criticize sophists for using words for worldly purposes, without seeking wisdom and truth, two notions close to them. In his book Sophistic Refutations, Aristotle goes as far as accusing them of using paralogisms, i.e. false and sometimes deliberately misleading reasoning.

Aristotle discusses psychology in On the Soul, which deals with the question from an abstract point of view, and in Parva Naturalia. The Aristotelian conception of psychology is profoundly different from that of the moderns. For him, psychology is the science that studies the soul and its properties. Aristotle approaches psychology with some perplexity as to how to proceed with the analysis of psychological facts, and whether it is a natural science. In On the Soul, the study of the soul is already in the domain of natural science, in Parts of the Animals. A body is a matter that possesses life in potential. It acquires real life only through the soul which gives it its structure, its breath of life. According to Aristotle, the soul is not separated from the body during life. It is only separated when death occurs and the body no longer moves. Aristotle conceives of the living being as an animate body (ἔμψυχα σώματα, empsucha sômata), i.e., endowed with a soul – which is called anima in Latin and psuchè in Greek. Without the soul, the body is not animated, not alive. Aristotle writes about this: “It is a fact that once the soul has disappeared, the living being no longer exists and none of its parts remain the same, except for its external configuration, as in the legend of the beings turned into stone”. Aristotle, in opposition to the first philosophers, places the rational soul in the heart rather than in the brain. According to him, the soul is also the essence or the form (eïdos morphè) of the living beings. It is the dynamic principle that moves them and guides them towards their own ends, that pushes them to realize their potentialities. As all living beings have a soul, it follows that animals and plants fall within the scope of psychology. However, not all living beings have the same soul, or rather, not all souls have the same functions. The soul of plants has only a vegetative function, responsible for reproduction, that of animals has both vegetative and sensitive functions; the soul of human beings has three functions: vegetative, sensitive and intellectual. To each of the three functions of the soul corresponds a faculty. To the vegetative function, which is found in all living beings, corresponds the faculty of nutrition, because food as such is necessarily linked to living beings; to the sensitive function corresponds perception; to the intellectual function corresponds the mind or reason (νοῦς, noûs), i.e., “the part of the soul through which we know and understand” (On the Soul, III 4, 429 a 99-10). The mind is at a higher level of generality than perception and can reach the abstract structure of what is studied. To these three functions, Aristotle adds desire, which allows us to understand why an animate being engages in an action in view of a goal. He assumes, for example, that man desires to understand.


The science of biology was born from the meeting on the island of Lesbos between Aristotle and Theophrastus. The first one oriented his studies towards animals and the second one towards plants. As far as Aristotle is concerned, the works devoted to biology represent more than a quarter of his work and constitute the first systematic study of the animal world. They will remain without equal until the 16th century: the earliest is History of Animals, in which Aristotle often accepts common opinions without verifying them. In Parts of the Animals, he goes back on some earlier assertions and corrects them. The third work, Generation of Animals, is the latest, because it is announced in the previous one as a complement. It deals exclusively with the description of sexual organs and their role in reproduction, both in vertebrates and invertebrates. One part deals with the study of milk and sperm, as well as the differentiation of the sexes. In addition to these three major works, there are shorter books dealing with a particular subject, such as Du Mouvement des animaux or Marche des animaux. This last book illustrates the author”s method: “to start from the facts, to compare them, then by an effort of reflection to try by understanding them to grasp them with exactitude”.

Nothing is known about the research he conducted before writing these books; Aristotle left no indication of how he gathered the information and how he processed it. For James G. Lennox, “it is important to keep in mind that we are studying texts that present, in a theoretical and highly structured way, the results of a real investigation of which we know few details. It is clear, however, that Aristotle worked as a team, especially for historical research, and that “the Lyceum was from the beginning the center of a collective scientific activity, one of the oldest that we can reach”. The school gathered around Aristotle having taken “the habit of concrete investigation carried out with method and rigor”, “observation and experiment played a considerable role in the birth of a whole part of the work”.


In Parts of the Animals, composed around 330, Aristotle begins by establishing elements of method. The study of facts must not neglect any detail and the observer must not let himself be disgusted by the most repulsive animals, because “in all natural productions there is something admirable” and it is up to the scientist to discover in view of what an animal possesses any particularity. Such a teleology allows Aristotle to see in the data he observes an expression of their form. Noting that “no animal has both tusks and horns” and that “an animal with one hoof and two horns has never been observed”, Aristotle concludes that nature gives only what is necessary. Similarly, seeing that ruminants have several stomachs and bad teeth, he deduces that one compensates for the other and that nature proceeds to some kind of compensation.

Aristotle approaches biology as a scientist and seeks to identify regularities. He notes in this respect: “the order of nature appears in the constancy of phenomena considered either as a whole or in the majority of cases” (, 663 b 27-8): if monsters (ferae), such as the five-legged sheep, are exceptions to natural laws, they are nevertheless natural beings. Simply, their essence or form does not act in the way it should. For him, the study of the living is more complex than that of the inanimate. Indeed, the living being is an organized whole from which one cannot detach without problem a part, as in the case of a stone. Hence the necessity to consider it as a whole (holon) and not as a shapeless totality. Hence, also, the necessity to study the part only in relation to the organized whole of which it is a member.

Sometimes, however, the desire to accumulate as much information as possible leads him to retain inaccurate statements without examining them:

“A work such as Recherches sur les animaux is essentially ambiguous in character: one finds in it, side by side one might say, meticulous, delicate observations, for example precise data on the structure of the visual apparatus of the mole or on the conformation of the teeth in man and animal, and on the contrary completely unacceptable assertions, which constitute serious and sometimes even gross errors, such as these: the testaceans are animals without eyes, the woman does not have the same number of teeth as the man, and other errors of the same kind. “

In spite of these flaws due to hasty generalizations, especially in History of Animals, Aristotle often expresses doubts about assertions supported by his predecessors, refusing, for example, to believe in the existence of horned snakes or of an animal with three rows of teeth. He readily criticized naïve beliefs and contrasted them with precise and personal observations of great accuracy. In short, he left “a work that is incomparable for its wealth of facts and ideas, especially if one looks back to the time in which it was born”, justifying this statement by Darwin: “Linnaeus and Cuvier have been my two gods in very different directions, but they are only schoolboys compared to the old Aristotle”.

Aristotle does not content himself with describing physiological aspects, but is also interested in animal psychology, showing that “the conduct and the kind of life of animals differ according to their character and their mode of feeding, and that in most of them there are traces of a true psychological life analogous to that of man, but of a much less marked diversity of aspects”.

All indications are that the biology books were accompanied by several books of anatomical plates established after meticulous dissections, but unfortunately disappeared. These represented in particular the heart, the vascular system, the stomach of ruminants and the position of certain embryos. The observations concerning embryogenesis are particularly remarkable: “the early appearance of the heart, the description of the eye of the chick, or the detailed study of the umbilical cord and the cotyledons of the womb are of perfect accuracy. He thus observed chick embryos at various stages of their development, after a brood of three days, ten days or twenty days -synthesizing observations that were numerous and continuous.

Classification of living beings

Aristotle tried to classify animals in a coherent way, while using common language. His basic distinctions are genus and species, distinguishing between blood animals (vertebrates) and non-blood animals or invertebrates (he did not know about the complex invertebrates with certain types of haemoglobin). The blood animals are first divided into four major groups: fish, birds, oviparous quadrupeds and viviparous quadrupeds. Then he enlarged this last group to include cetaceans, seals, monkeys and, to some extent, man, thus constituting the great class of mammals. Similarly, he distinguishes four genera of invertebrates: crustaceans, mollusks, insects and testaceans. Far from being rigid, these groups have common characteristics because they belong to the same order or phylum. Aristotle”s classification of living things contains elements that were used until the 19th century. As a naturalist, Aristotle does not suffer from the comparison with Cuvier:

“The result reached is astonishing: starting from common data, and making them undergo, apparently, only rather light modifications, the naturalist arrives nevertheless at a vision of the animal world of an objectivity and a quite scientific penetration, clearly exceeding the attempts of the same order which were tried until the end of the XVIIIth century. In addition, and as if without effort, great hypotheses are suggested: the assumption of an influence of the environment and the conditions of existence on the characters of the individual (the idea of a continuity between the living beings, of the man to the humblest plant, continuity which is not homogeneity and goes hand in hand with the deep diversities; the thought finally that this continuity implies a progressive, timeless development since the world is eternal. “

Aristotle believes that creatures are classified according to a scale of perfection ranging from plants to man. His system has eleven degrees of perfection ranked according to their potentiality at birth. The highest animals give birth to warm, wet creatures, the lowest to dry, cold eggs. For Charles Singer, “nothing is more remarkable than the efforts that the relations between living things constitute a scala naturæ or “scale of beings.

In total, there are 508 animal names “very unevenly distributed among the eight major genera”: 91 mammals, 178 birds, 18 reptiles and amphibians, 107 fishes, 8 cephalopods, 17 crustaceans, 26 testaceans and 67 insects and relatives.

Physics as a science of nature

Physics is the science of nature (“physics” comes from the Greek phusis (ϕύσις) meaning “nature”). For Aristotle, its object is the study of inanimate beings and their components (earth, fire, water, air, ether). This science does not aim at transforming nature as it does today. On the contrary, it seeks to contemplate it.

According to Aristotle, natural beings, whatever they are (stone, living beings, etc.), are made up of the first four elements of Empedocles, to which he adds the ether, which occupies what is above the Earth.

Nature, according to Aristotle, has an internal principle of movement and rest. The form, the essence of beings, determines the end, so that, for the Stagirite, nature is at the same time a driving cause and an end (Part, an., I, 7, 641 a 27). He writes (Meta., Δ4, 1015 ab 14-15) : “Nature, in its primitive and fundamental sense, is the essence of beings which have, in themselves and as such, their principle of movement”. He also distinguishes between natural beings, which have this principle in themselves, and artificial beings, created by man and which are subjected to a natural movement only by the matter which composes them, so that for him, “art imitates nature”.

Moreover, in Aristotle”s thought, nature is endowed with a principle of economy, which he translates into his famous precept: “Nature does nothing in vain nor anything superfluous”.

Four causes

Aristotle develops a general theory of causes that runs through the whole of his work. If, for example, we want to know what a bronze statue is, we will have to know the material of which it is made (material cause), the formal cause (what gives it form, e.g. the statue represents Plato), the efficient cause (the sculptor) and the final cause (keeping Plato”s memory). For him, a complete explanation requires to have been able to bring these four causes to light.

Substance and accident, act and power, change

For Aristotle, substance is that which necessarily belongs to the thing, whereas accident is “that which really belongs to a thing, but which does not necessarily or most of the time belong to it” (Metaphysics, Δ30, 1025 a 14).

Potency or potentiality (δύναμις dunamis) echoes what the being could become. For example, a child can, in potency, learn to read and write: He has the capacity. The power is the principle of imperfection, and this one is modified by the act, which involves the change. The act (energeïa) “is what produces the finished object, the end. It is the act, and it is in view of the act that power is conceived” (Metaphysics, Θ8, 1050 a 9). Entelechy (en, telos, echein) “literally means having (echein) in itself its end (τέλος telos), the gradual attainment of its own end and essence”.

These notions allow the philosopher to explain motion and change. Aristotle distinguishes four types of movement: in substance, in quality, in quantity and in place. For him, movement is due to a couple: an active, external and operative power (or potentiality) and a passive capacity or internal potentiality that is in the object undergoing the change. The entity causing a change transmits its form or essence to the affected entity. For example, the form of a statue is found in the soul of the sculptor, before materializing through an instrument in the statue. For Aristotle, in the case where there is a chain of efficient causes, the cause of movement resides in the first link.

For there to be change, there must be a potentiality, that is to say that the end inscribed in the essence has not been reached. However, the actual movement does not necessarily exhaust the potentiality, does not necessarily lead to the full realization of what is possible. Aristotle distinguishes between natural change (phusei), or in accord with nature (kata phusin), and forced change (βίαι biai) or contrary to nature (para phusin). Aristotle thus somehow assumes that nature regulates the behavior of entities and that natural and forced changes form an opposite pair. The movements we see taking place on Earth are rectilinear and finite; the stone falls and remains at rest, the leaves fly and fall, etc. They are therefore imperfect, as the natural and forced changes are. They are therefore imperfect, as is the sublunary world in general. On the contrary, the supra-lunar world, that of the ether “unengendered, indestructible, free from growth and alteration”, is that of circular, eternal motion.

Movement and evolution have no beginning, because the occurrence of change presupposes an earlier process. So Aristotle postulates that the universe depends on an eternal motion, that of the celestial spheres, which itself depends on an eternally acting mover. However, unlike what usually happens with him, the first mover does not transmit the acting power in a process of cause and effect. Indeed, for Aristotle, eternity justifies the causal finitude of the universe. To understand this, we must remember that, according to him, if men are born without end, by begetting through parents (infinite causal chain), without the sun, without its heat (finite causal chain), they could not live.

For Aristotle, “it is by perceiving motion that we perceive meaning” (Phys., IV, 11, 219 a 3). However, the eternal beings (the celestial spheres) escape time, while the beings of the sublunary world are in time which is measured from the movements of the celestial spheres. As this movement is circular, time is also circular, hence the regular return of the seasons. Time allows us to perceive change and movement. It marks a difference between a before and an after, a past and a future. It is divisible but without parts. It is neither body nor substance and yet it is.

He rejects the point of view of the atomists and considers that it is absurd to want to reduce the change to insensible elementary movements. For him, “the distinction of the “power” and the “act”, of the “matter” and the “form”, allows to account for all the facts”.

Sublunar and supralunar world

In the Treatise on the Sky and Meteorology, Aristotle demonstrates that the Earth is spherical and that it is absurd to present it as a flat disk. He argues that lunar eclipses show curved sections and that even a slight shift from north to south causes a clear alteration of the horizon line lies in the idea that the movement of solids would be naturally centripetal: such a movement has originally driven the solids around the center of the Universe, their reciprocal thrusts achieving a spherical shape, the Earth. He divided the globe into five climatic zones corresponding to the inclination of the sun”s rays: two polar zones, two temperate habitable zones on either side of the equator, and a central zone at the equator that was rendered uninhabitable because of the high heat that reigned there. He estimated the circumference of the Earth at 400,000 stadia, or about 60,000 km. Aristotle”s geocentric conception, together with that of Ptolemy, dominated thinking for more than a thousand years. Aristotle”s conception of the cosmos, however, was largely derived from Eudoxus of Cnidus (whose theory of the spheres he perfected), with the difference that Eudoxus did not defend a realistic position, as did Aristotle. Ptolemy does not support this realistic position either: his theory and that of Eudoxus are for them only theoretical models that allow calculation. It is therefore the influence of Aristotelianism that makes the Ptolemaic system appear as the “reality” of the cosmos in philosophical reflections, until the 15th century.

Aristotle distinguishes two great regions in the cosmos: the sublunary world, ours, and the supralunary world, that of the sky and the stars, which are eternal and do not admit any change because they are made up of ether and possess a truly divine life which is sufficient for itself. The Earth is necessarily immobile but is at the center of a sphere animated by a continuous and uniform rotational movement; the rest of the world participates in a double revolution, one proper to the “first Heaven” making a diurnal revolution from East to West, while the other makes an inverse revolution from West to East and is decomposed into as many distinct revolutions as there are planets. This model is further complicated by the fact that it is not the planets that move, but the translucent spheres on whose equator they are fixed: three spheres were needed to explain the movement of the moon, but four for each of the planets.

Influence of cosmology on science and on the representation of the world

According to Alexandre Koyré, Aristotelian cosmology leads, on the one hand, to the conception of the world as a finite and well-ordered whole, where the spatial structure embodies a hierarchy of value and perfection: “Above” the heavy and opaque earth, the center of the sublunary region of change and corruption, “rise the celestial spheres of the imponderable, incorruptible and luminous stars…”. On the other hand, in science, this leads to see space as a “differentiated set of intramundane places”, which are opposed to “the space of Euclidean geometry – homogeneous and necessarily infinite extension”. This has as a consequence to introduce in the scientific thought considerations based on the notions of value, perfection, meaning or end, as well as to link the world of values and the world of facts.

The word metaphysics is not known to Aristotle, who uses the expression first philosophy. The work called Metaphysics is composed of rather heterogeneous notes. The term “metaphysics” was attributed to it in the first century because the writings that compose it were classified “after the Physics” in the library of Alexandria. Since the prefix meta can mean after or beyond, the term “meta-physics” (meta ta phusika) can be interpreted in two ways. First, it is possible to understand that the texts are to be studied after physics. It is also possible to understand the term as meaning that the object of the texts is hierarchically above physics. Even if, in both cases, it is possible to perceive a certain compatibility with the Aristotelian term of first philosophy, the use of a different word is often perceived by specialists as a reflection of a problem, especially since the texts gathered under the name of metaphysics are crossed by two distinct questionings. On the one hand, first philosophy is seen as “science of first principles and first causes”, i.e. of the divine; this is a questioning now called theological. On the other hand, books Γ and K are crossed by an ontological questioning about “the science of being as being”. So that we sometimes speak of an “onto-theological orientation” of the first philosophy. To complicate matters, Aristotle seems, in some books (book E in particular), to introduce the ontological question of book gamma (what is it that makes everything that is?) inside a theological type question (what is the first cause that brings to being the whole of what is?)

Physics and metaphysics

In Book E chapter 1, Aristotle notes, “Physics studies separate (χωριστά) but not immobile beings, whereas the primary science has for its object beings that are both separate and immobile If there were no other substance than those constituted by nature, physics would be primary science. But since there is an immobile substance, then the science of this substance must be prior to the sensible things of the world of phenomena, and metaphysics must be the first philosophy. And the task of this science will be to consider the being as such and the concept and the qualities that belong to it as being” (E 1, 1026 a 13-32). Also, if physics studies the form-matter (ἔνυλα εἴδη) set of the visible world, metaphysics or first philosophy studies form as form i.e., the divine “present in this immobile and separate nature” (E1, 1026 a 19-21). For a specialist like A. Jaulin, metaphysics thus studies “the same objects as physics, but from the perspective of the study of form”.

For Aristotle, while physics studies natural movements, i.e. those caused by the principle proper to matter, metaphysics studies “unmoved engines”, those which make things move without being themselves moved: “The two sensible substances are the object of Physics, because they imply movement; but the immobile substance is the object of a different science.

From then on, “Metaphysics is indeed the science of the essence, and on the other hand, are universal the “axioms” which express at the bottom the nature of God”.

God as the prime mover and the philosophy of religion

The conventional representation we have of Aristotle makes him a purely intellectualist metaphysician; yet, according to Werner Jaeger, Aristotle must also be considered as the founder of the philosophy of religion because his dialectic is “inspired from within by a lively religious feeling, with which all parts of the logical organization of his philosophy are penetrated and informed”. After Plato”s theology of old age, Aristotle provides the first proof of God”s existence in his dialogue On Philosophy (Περὶ φιλοσοφίας), writing in book III fragment 16: “It may be considered that in any realm where there is a hierarchy of degrees, and therefore a greater or lesser approximation to perfection, there is necessarily something absolutely perfect. Now, given that, in everything that is, such a gradation of more or less perfect things is manifested, there is therefore a being with absolute superiority and perfection, and this being can well be God “. Now, it is precisely nature, a reign of strictly hierarchical Forms, which is governed according to Aristotle by this gradation : every inferior thing is linked to another which is superior to it. In the realm of existing things, there is therefore also a thing of ultimate perfection, the highest final cause and principle of all the rest. This ontological argument, linked to the teleological argument according to Aristotle”s Physics, constitutes what the great scholastics will call the argumentum ex gradibus. It is the first great attempt to treat the problem of God in a scientific way. This scientific speculation, however, does not exclude the personal experience of the intimate intuition of God, especially in the piety with which Aristotle evokes the divinity of the cosmos. “Aristotle”s contemplation of the immutable order of the stars, intensified to the point of becoming a religious intuition of God”, is in line with Plato and is not without announcing Kant”s wonderment.

In the book entitled Metaphysics, man”s knowledge of God is identified with God”s knowledge of himself. The self is the spirit, the νοῦς noûs, which is said to “come from without” (θύραθεν εἰσίων) and to be “the divine in us,” (τὸ θεῖον ἐν ἡμῖν). And it is through the νοῦς noûs that the knowledge of God enters us, Aristotle thus defines him as the thought of thought (νοήσεως νόησις, “noeseos noesis”), i.e., as a being that thinks its own thought, intelligence and the act of intelligence being one and the same thing in god: “God is happy, he is too perfect to think himself anything but himself. The supreme Intelligence therefore thinks itself…, and its Thought is thought of thought”. He is in this sense a pure form or Act, without matter, which launches the whole of the movements: indeed, Aristotle describes god like the first immutable and incorruptible engine, and which, thereafter, actualizes the whole of what is. He perpetually enjoys pure and simple pleasure, for there is not only an activity of movement – transitive or fabricating activity in the Aristotelian sense of the Greek ἔργον – but also an immobile, immanent, perfect activity, which reaches its end at all times, and this “activity of stillness,” ἐνέργεια ἀκινησίας, the type of activity par excellence, is fully realized in the pure Act which Aristotle calls “the perfect eternal living,” ζῷον ἀΐδιον ἄριστον, for the act of intelligence is life: ἡ γὰρ νοῦ ἐνέργεια ζῳή.

In Aristotle, god, defined at the end of his work On Prayer as “the νοῦς or something superior to the νοῦς”, is absolutely transcendent, so that it is difficult to describe him otherwise than in a negative way, that is to say, in relation to what men do not have. For Céline Denat, “The Aristotelian God, enjoying a perfect life consisting in the pure activity of intelligible contemplation, certainly constitutes in some way for man “an ideal”, the model of an existence devoid of the imperfections and the limits which are proper to us”. However, this negative theology, which will influence the neo-Platonists, is not assumed by Aristotle. Pierre Aubenque notes: “The negativity of theology is simply encountered in the mode of failure; it is not accepted by Aristotle as the realization of his project, which was unquestionably to make a positive theology”.

Aristotelian Ontology

The ontological question of being as being is not approached in Aristotle as the study of a matter constituted by being as being, but as the study of a subject, being, seen from the angle as being. For Aristotle, the word “being” has several meanings. The first meaning is that of substance (ousia), the second, that of quantity, qualities, etc., of this substance. Nevertheless, for him, the science of being as being is mainly centered on the substance. To ask the question “what is being?” is to ask the question “what is substance?” Aristotle discusses in the book of Metaphysics the principle of non-contradiction (PNC), that is, “the same attribute cannot both be attributed and not be attributed to the same subject” (Meta 1005 b 19). If this principle is central for Aristotle, he does not try to prove it. He prefers to show that this assumption is necessary, if words are to have meaning.

In Metaphysics Z, 3, Aristotle presents four possible explanations of what the substance of x is. It can be “(i) the essence of x, or (ii) universal predicates of x, or (iii) a genus to which x belongs, or (iv) a subject of which x is the predicate”. For Marc Cohen, “a substantial form is the essence of the substance, and this corresponds to a species. Since a substantial form is an essence, it is what is denoted by the definiens of the definition. Since only universals are definable, substantial forms are universals”. The problem is that if Aristotle in Metaphysics Z, 8 seems to think that substantial forms are universals, in Metaphysics Z, 3, he excludes this possibility. Hence two lines of interpretation. For Sellars (1957), Irwin (1988), substantial forms are not universals and there are as many substantial forms as there are particular types of a thing. For others, (Woods (1967), Loux (1991)), Aristotle does not mean in Z, 13 that universals are not a substance but something more subtle which does not oppose “that there is only one substantial form for all particulars belonging to the same species”.

In Z, 17, Aristotle hypothesizes that substance is both principle and cause. Indeed, if there are four types of causes (material, formal, efficient and final), the same thing can belong to several types of causes. For example, in the De Anima (198 a 25), he argues that the soul can be an efficient, formal and final cause. So the essence is not only a formal cause, it can also be an efficient and final cause. To put it simply, for Aristotle, Socrates is a man “because the form or essence of man is present in the flesh and bones that constitute” his body.

If Aristotle, in Metaphysics Z, distinguishes between matter and body, in Book Θ he distinguishes between reality and potentiality. Just as form takes precedence over matter, reality takes precedence over potentiality for two reasons. First, reality is the end; it is for it that potentiality exists. Secondly, potentiality may not become a reality, it is therefore perishable and as such inferior to what is because “what is eternal must be entirely real”.

For Pierre Aubenque, Aristotle”s ontology is an ontology of the split between the immutable essence and the sensible essence. So that it is the mediation of the dialectic which makes possible a unity “properly ontological, that is to say which holds only to the discourse that we hold on it and which would collapse without it”.

Aristotle tackled ethical questions in two works, the Ethics to Eudemus and the Nicomachean Ethics. The first one dates back to the period before the foundation of the Lyceum, between 348 and 355, and presents a first state of his thought on the subject, in a simple and accessible exposition, parts of which will be taken up later in the Nicomachean Ethics. The two books have more or less the same concerns. They start with a reflection on eudemonism, that is on happiness or fulfillment. They continue with a study on the nature of virtue and excellence. Aristotle also discusses the character traits necessary to achieve this virtue (arete).

For Aristotle, ethics is a field of practical science whose study should enable human beings to live a better life. Hence the importance of ethical virtues (justice, courage, temperance etc.), seen as a mixture of reason, emotions and social skills. However, Aristotle, unlike Plato, does not believe that “the study of science and metaphysics is a prerequisite for a full understanding of our good”. For him, the good life requires that we have acquired “the ability to understand on every occasion what actions are most in accordance with reason”. The important thing is not to follow general rules but to acquire “through practice the deliberative, emotional and social skills that enable us to put our general understanding of the good into practice”. It does not aim to “know what virtue is in its essence” but to show how to become virtuous.

Aristotle considers ethics as an autonomous field that does not require expertise in other fields. Moreover, justice is different from and inferior to the common good. Thus, unlike Plato for whom justice and the common good must be sought for themselves and for their results, for Aristotle, justice must be sought only for its consequences.

The good: a central notion

All action tends toward a good that is its end. What is called the supreme good, or the sovereign good, is called by Aristotle eudaimonia and designates both happiness and the good life, εὖ ζῆν eu zên. Being εὐδαίμων eudaimon is the highest end of the human being, the one to which all other ends (health, wealth, etc.) are subordinated. This is why the philosopher Jean Greisch proposed to translate the term eudaimonia (εὐδαιμονία), as fulfillment rather than happiness. For Aristotle, the supreme good has three characteristics: it is desirable by itself; it is not desirable for the sake of other goods; other goods are desirable for the sole purpose of attaining it. Thus Aristotle makes ethics a constitutive science of politics: “For the conduct of life, the knowledge of this good is of great weight and depends on the supreme and architectonic science par excellence (which) is obviously politics, for it determines which of the sciences are necessary in cities”. The ultimate end of the human being is also related to the ἔργον ergon, that is, to his task, his function, which for him consists in using the rational part of man in a way that is consistent with virtue (ἀρετή, “aretê”) and excellence. To live well, we must practice activities “that throughout our lives actualize the virtues of the rational part of the soul.”

There are various conceptions of happiness. The most common form is pleasure, but this type of happiness is proper “to the coarsest people” because it is within the reach of animals. A higher form of happiness is that given by the esteem of society, for “one seeks to be honored by sensible men and by those of whom one is known, and one wants to be honored for one”s excellence”. This form of happiness is perfectly satisfying because “the life of good people does not need pleasure to be added to it as an extra, but it has its pleasure in itself”. There is, however, an even greater happiness: it is that which comes from contemplation, understood as the search for truth, for that which is immutable, for that which finds its end in itself. This is something divine: “It is not as a man that one will live in this way, but according to the divine element that is present in us”. Aristotle devotes the whole of the last book of his Ethics to this form of happiness.

Wealth should not be confused with happiness: “As for the life of the businessman, it is a life of constraint, and wealth is obviously not the good we seek: it is only a useful thing, a means to another end.

Theory of virtues

Aristotle distinguishes two kinds of virtues: intellectual virtues, which “depend to a large extent on the teaching received” and moral virtues, which are “the product of habit”: “It is by practicing just actions that we become just, moderate actions that we become moderate, and courageous actions that we become courageous”. In both cases, these virtues are in us only in a state of power. All free men are born with the potentiality of becoming morally virtuous. Virtue cannot be merely good intention, it must also be action and realization. It depends on the character (ethos) and the habit of doing well that individuals must acquire. Prudence is practical wisdom par excellence.

Intellectual virtues include:

An intemperate person does not follow reason but emotions. Now, moral virtue is a middle way between two vices, one by excess and the other by defect: “It is quite a task to be virtuous. In all things, in fact, it is difficult to find the way”. There are four forms of excess in Aristotle: “(a) impetuosity caused by pleasure, (b) impetuosity caused by anger, (c) weakness caused by pleasure, (d) weakness caused by anger”.

“In everything, finally, we must beware of what is pleasant and of pleasure, because in this matter we do not judge with impartiality. A person who controls himself and shows temperance even though he is subject to the passions (pathos) retains the strength to follow reason and shows self-discipline. This is strengthened by habit: “It is by abstaining from pleasures that we become moderate, and once we have become moderate, it is then that we are most capable of practicing this abstention”.

On the other hand, there are people who do not believe in the value of virtues. Aristotle calls them evil (kakos, phaulos). Their desire for domination or luxury knows no bounds (πλεονεξία pleonexia) but leaves them unsatisfied, as they are unable to achieve inner harmony. Like Plato, he believes that inner harmony is necessary to live a good life. We live a bad life when we allow ourselves to be dominated by irrational psychological forces that drive us toward goals outside ourselves.

Desire, deliberation and rational wish

“There are three predominant factors in the soul that determine action and truth: sensation, intellect and desire. Unfortunately, our desires do not necessarily lead to good, but can lead to immediate satisfaction, to dispersion: we desire something because it seems good to us, rather than it seems good because we desire it. To act well, man must be guided by reason: “Just as a child must live in conformity with the prescriptions of his governor, so the concupiscible part of the soul must conform to reason”. In this way, he can reach the rational wish and then, thanks to the study of the means and to the deliberation, arrive at the thoughtful choice.

“There are three factors that lead to our choices, and three factors that lead to our repulsions: the beautiful, the useful, the pleasant and their opposites, the ugly, the harmful and the painful”. Deliberation leads to rational choice, which concerns the means to achieve the end: “We deliberate not on the ends themselves, but on the means to achieve the ends”. Virtue and vice result from voluntary choices: “Choice is not common to man and to beings without reason, unlike what happens with concupiscence and impulsivity. acts by choice and not by concupiscence”.

“Aristotle does not yet use the notions of free will, freedom, responsibility”, but lays the foundations on which these notions will be built, by distinguishing between voluntary and involuntary actions. The latter cannot be related to our will and we cannot therefore be held responsible for them. However, for Aristotle, ignorance does not necessarily lead to forgiveness. Indeed, there are cases where the ignorance of human beings must be sanctioned because it was up to them to inform themselves. Thus, when we sometimes realize our ignorance and error, we recognize that we have done wrong. However, in cases where men are subject to external constraints that they cannot resist, they are not responsible for their conduct. In general, for Aristotle, the will is about the end sought and the choice about the means to that end. While Plato insists on the end and holds the means as subordinate, subservient to the ends, Aristotle questions the dissonance between ends and means. Thus, for the Stagirite, ends and means are equally important and interact.

Prudence and deliberation on the means to an end

For Aristotle, the “phronêsis” is not only the Latin “prudentia”. It is the consequence “of a split within reason, and the recognition of this split as a condition for a new critical intellectualism”. So that phronêsis is not the virtue of the reasonable soul, but that of the part of this soul which relates to the contingent. Whereas for Plato the split is between the Forms (or Ideas) and the contingent or rather, the shadow, the copy of the forms, with Aristotle, it is the real world which is itself split in two. This splitting does not imply, as in Plato, a hierarchy between the two parts of the reasonable soul. For the Stagirite, phronêsis stems from the inability of science “to know the particular and the contingent, which are however the proper domain of action”. Phronêsis serves to fill “the infinite distance between the real effectiveness of the means and the realization of the end”. Phronêsis is linked to intuition, to the glance, also it is not indecision. Pierre Aubenque notes on this subject: “At the same time man of thought and action, heir in that of the heroes of the tradition, the phronimos unites in him the slowness of the reflection and the immediacy of the glance, which is only the sudden blossoming of that one: he unites the meticulousness and the inspiration, the spirit of forecast and the spirit of decision”.

Theory of measurement

For Aristotle, each ethical virtue is balanced between two excesses. For example, a courageous person is situated between the coward who is afraid of everything and the reckless person who is afraid of nothing. However, virtue is not quantifiable, it is not the arithmetic mean between two states. For example, in some cases, a great deal of anger will be required, while in another circumstance a very small amount of anger will be required. This interpretation of the measure is generally accepted. On the other hand, the interpretation that to be virtuous one must reach a goal that lies between two options is quite widely rejected. Indeed, for Aristotle, the important thing is not to be “lukewarm” but to discover what is appropriate in the present case. To act virtuously, one must act in such a way as to be “καλός kalos” (noble, or beautiful), for men have the same attraction to ethical activities as they have to the beauty of works of art. True to his educational principles, Aristotle considers that young people should learn what is “καλόν kalon” and develop an aversion to what is “αἰσχρόν aischron” (ugly or shameful).

The theory of measure helps to understand which qualities are virtuous, such as courage or temperance, because they are situated between two extremes, and which emotions (spite, envy), which actions (adultery, theft, murder) are bad in all circumstances. Contrary to Plato, Aristotle takes a great interest in the family and is very concerned with the virtues that are necessary for it.

The theory of measurement is not part of the deliberative process turned towards the study of the means to achieve a goal. It belongs to the process which leads to virtue and which allows to define the good goal: “Moral virtue, indeed, ensures the rectitude of the goal we pursue, and prudence that of the means to reach this goal”.

The Politics is one of the oldest treatises on political philosophy in ancient Greece and the only ancient work that analyzes the problematic of the city as well as the concept of slavery. In it, Aristotle examines how the city (in Greek: πόλις, polis) should be organized. He also discusses Plato”s conceptions in The Republic and The Laws, as well as various models of constitutions.


Political science (πολιτικὴ ἐπιστήμη politikê epistêmê) is first of all a practical science that seeks the good and happiness of citizens: “The most perfect state is obviously the one in which each citizen, whoever he may be, can, thanks to the laws, practice virtue the best, and secure the most happiness”. Politics is also a productive science when it deals with the creation, preservation and reform of political systems. In the Nicomachean Ethics, Aristotle argues that political science is the most important science of the city, the one that should be studied first by citizens, even before military science, housekeeping (which would much later become, with Adam Smith, economics), and rhetoric. Political science is not limited, as it is nowadays, to political philosophy but also includes ethics.

Ethics and politics have in common the search for the Good. They participate in technê politikê, or political art, whose object is, at the same time, the common good, and the good of individuals.

For a society to be sustainable, it must first be just. Justice serves to qualify our relations with our fellow men when they are marked by friendship. It is therefore the complete virtue which makes us seek, at the same time, our good and that of others. In practice, it is useful that it is supported by laws that will say what is just and unjust. The relationship between justice and law is twofold. Indeed, justice, which is first and foremost an ethical virtue, also serves as a norm for the law.

According to Aristotle, man can only live among men: “Without friends no one would choose to live, even if he had all other goods”. He distinguishes three types of friendship: useful friendship (friendship based on pleasure (we are happy, for example, to play cards with someone) and true friendship where we “love the other for himself”. This last type of friendship is in itself a virtue that contributes to the common good. If a city can live without this form of virtue, to endure it must at least reach the concord which allows to arrive at a community of interests: “Friendship also seems to constitute the link of the cities, and the legislators seem to attach a greater price to it than to justice itself: indeed, concord, which seems to be a feeling close to friendship, is what the legislators seek above all, whereas the spirit of faction, which is its enemy, is what they chase with the most energy”.

Presuppositions of Aristotle”s political philosophy

According to Fred Miller, Aristotle”s political philosophy is based on five principles:


Aristotle devotes several chapters of his Politics to education. He makes it “a strict duty of the legislator to legislate on education” and considers that “the education of children must be one of the main objects of the legislator”s care”. Clearly opposed to Plato”s collectivism, he sees in education the means “to bring back to the community and to the unity the State, which is multiple”. He thus devotes a long reflection to the modalities that it must take: “education must necessarily be one and identical for all its members” and “the education of children and women must be in harmony with the political organization”. Aristotle wants that education necessarily includes “two distinct periods, from seven years until puberty, and from puberty until twenty-one years”. As for the pedagogical objectives, he opts for a position that Marrou judges to be of “remarkable finesse”:

“Physical education, far from aiming to select champions, must propose as its goal the harmonious development of the child; in the same way, musical education will reject any pretension to compete with professionals: it will aspire only to train an enlightened amateur, who will have practiced musical technique himself only insofar as such direct experience is useful for forming his judgment.”

Aristotle is critical of Athens because this city did not “understand that education was not only a political problem, but perhaps the most important one”; he is no more tender towards Sparta which aims first of all at inculcating warlike virtues in the young. The philosopher speaks in precursor, because at his time “the existence of a true public instruction assumed by the State remained an originality of the aristocratic cities (Sparta, Crete)”. It is only at the Hellenistic time that the young girls of the principal cities will attend the same way as the boys the primary and secondary schools or the palestra and the gymnasium.

The city and political naturalism

Aristotle, in Book I of his Politics, considers the city and the law as natural. According to him, human beings first formed couples in order to reproduce, then created villages with natural masters, capable of governing, and natural slaves, used for their labor power. Finally, several villages joined together to form a city-state.

For Aristotle, man is “a political animal”, i.e. a being who lives in a city (in Greek: polis). He sees the proof that men are social beings in the fact that “nature, which does nothing in vain, has endowed them with language, which makes them capable of sharing moral concepts such as justice”. Man is not the only social animal, for bees, wasps, ants and cranes are also capable of organizing themselves for a common purpose.

The notion of nature, and in particular that of human nature, is not fixed in Aristotle. Indeed, he considers that the human being can transform his status into a natural slave, or even into a semi-divine human being.

Policy actors

Only the one who can exercise the functions of judge and magistrate is a full-fledged citizen: “The eminently distinctive feature of the true citizen is the enjoyment of the functions of judge and magistrate”. But these functions require a virtuous character of which many are incapable. It is thus necessary to exclude from the status of citizen those who would be unable to govern the city. As these functions are granted by a constitution and as constitutions vary between cities, there are cities where very few are full citizens.

Aristotle has a hierarchical vision of society: he ranks the free man above other human beings such as slaves, children and women. He writes:

“Thus, the free man commands the slave quite differently from the husband to the wife, and the father to the child; and yet the essential elements of the soul exist in all these beings; but they are in very different degrees. The slave is absolutely deprived of will; the woman has one, but in sub-order; the child has only an incomplete one.”

He places in an inferior class the ploughmen, craftsmen, tradesmen, sailors or fishermen, and all “people of too mediocre fortune to live without working”. All these people are indeed unable to perform a magistrate”s function and to devote themselves to the pursuit of happiness through philosophy, because this requires a lot of free time. The most important task of the politician is that of legislator (Nomothete). Aristotle often compares the politician to a craftsman, for like the latter, he creates, uses and reforms when necessary the legal system. But his operations must be carried out in accordance with universal principles. For Aristotle, the citizen, that is, the one who has the right (ἐξουσία, exousia) to participate in public life, has a much more active role, is much more involved in the management of the city than in our modern democracies.

General theory of constitutions and citizenship

However, in order for it to flourish, the city must be well governed. A happy city is one that is governed by a good constitution, “the constitution being defined by the organization of the various magistracies”. It is important that the constitution be accepted by all citizens and, to this end, that all classes participate in some way in power. Also he rejects the system advocated by Hippodamos of Miletus because it excludes from the power the two working classes: “But if the craftsmen and the laborers are excluded from the government of the city, how will they be able to have any attachment for it? He analyzes other constitutions, in particular those of Sparta, Carthage, Crete and Athens.

According to Aristotle, there are two main types of constitution: correct constitutions, which lead to the good of all, and deviant constitutions, which benefit only those who rule. He distinguishes three forms of correct constitutions: kingship, aristocracy and constitutional government. Aristotle differentiates the forms of government according to the number of rulers: one in tyranny and kingship, a few in aristocracy or oligarchy and many in democracy and republic. Aristocracy” in his view does not necessarily refer to a privilege of birth but to the best in the sense of personal merit, while “democracy” or “popular rule” refers to the exercise of power by the people.

Rulers must be chosen on the basis of their political excellence, that is, they must be capable of governing not for the benefit of a particular group, but for the good of all: “all claims (to rule) made in the name of any other criterion (wealth, birth, freedom) are, as such, disqualified and dismissed. According to Aristotle, the City-State is not intended, as the oligarchs believe, to maximize their wealth, nor, as the poor who advocate “democracy” believe, to promote equality. Its purpose is to make possible a good life of excellent actions.

A constitution is excellent if it ensures the happiness of its citizens and if it is capable of lasting. According to Miller, the least bad constitution would be one in which power is controlled by a large middle class. There are several reasons for this. First, being neither very rich nor very poor, members of this class are more naturally moderate and inclined to follow reason than others. Second, they are less likely to join violent and intractable factions, which makes cities more stable:

“It is therefore also clear that the best political community is that which is constituted by average people, and that the cities which can be well governed are those in which the middle class is numerous and at best stronger than the other two, or at least than one of the two, for its contribution tips the scales and prevents contrary excesses.”

However, according to Pierre Pellegrin, it would be vain to try to know if Aristotle is “partisan of aristocracy, of democracy or of a “government of the middle classes”, because this question “does not have place”. Aristotle, in fact, while affirming that there is “an excellent constitution”, and while recognizing that the establishment of this one is necessarily progressive, warns that the situations are diverse according to the local culture and that “in each concrete situation there is one and only one constitutional form which is excellent”. The only universal principle that is valid for all constitutions is that of proportional equality: “Each one must receive in proportion to his excellence”.

Without dealing systematically with the problem of laws, Aristotle shows their interdependence with the constitution: “a law that is just in one constitution would be unjust in another, because it contradicts the spirit of that constitution. the introduction of a new legislative provision can have devastating effects on the constitution”. He also shows the rivalry that arises between two cities governed by opposite systems: “when they have at their doors a state constituted on a principle opposed to their own, or when this enemy, however distant, possesses great power. See the struggle of Sparta and Athens: everywhere the Athenians overthrew oligarchies, while the Lacedemonians overthrew democratic constitutions”.

Influence of this work

As with most of Aristotle”s works, this one was not edited for publication, but was intended for his teaching. This results in gaps, inconsistencies and ambiguities due to the incomplete state of the text. Nor do we have ancient Greek commentaries as for the other treatises, nor an indirect tradition that could help make corrections or restore the authentic text in corrupted passages. But this does not alter the unity of structure of the work and of a thought that remains “the most important and richest contribution of antiquity in the field of political science”.

In his time, Aristotle”s political analysis did not have a strong influence, as many city-states had already lost their independence to Alexander the Great, for whom he was the tutor. Little commented on and long forgotten, the work was only rediscovered in the 13th century, when Aristotle”s thought was invoked in a reflection on Augustinism and later in the quarrel between the papacy and the empire.

Presentation of Aristotle”s thought

Aristotle discusses economic topics in Nicomachean Ethics 5.5 and Politics I, 8-10; in both cases, these are subsections within studies on more fundamental topics. In the Nicomachean Ethics, he differentiates between distributive justice (διανεμητικός dianemetikos), which deals with how honors, goods, and the like are to be distributed, and corrective justice (διορθωτικός diorthotikos). In the first case, justice does not consist in an equal distribution among unequal people, but in a balance perceived as just. In the second case, that of corrective justice, the Stagirite distinguishes between voluntary and involuntary exchanges. In the case of an involuntary exchange, justice only intervenes if there has been fraud and does not have to investigate whether there has been a fair price.

Aristotle explicitly recognizes the economic necessity of slavery at a time when mechanization did not exist: “if the shuttles wove by themselves; if the bow played the zither by itself, the entrepreneurs would do without workers, and the masters, without slaves”. His treatise on politics is even the only text of antiquity that studies slavery as a concept.

He also reflects on the nature of money, whose purely conventional aspect he affirms, because money has value only “by law and not by nature”. It is thanks to money that the exchange between different goods can be balanced. But a question haunts Aristotle, is money just an instrument of exchange or is it a substance that has its own end (telos)? He condemns interest lending and usury “because it is a mode of acquisition born of money itself, and does not give it the purpose for which it was created”. In Politics, he clearly states that money should only be used to facilitate the exchange of goods:

“Money should only be used for exchange, and the interest that is derived from it multiplies it, as the name given to it in the Greek language (tokos) sufficiently indicates; the beings produced here are absolutely similar to their parents. Interest is money from money, and of all acquisitions it is the most contrary to nature.

He warns against unbridled commercial acquisition – chrematistics – which “does not even have a limit to the goal it pursues, since its goal is precisely indefinite opulence and enrichment”.

Aristotle perceived the danger posed to the city by the development of the market economy. The economic part of his work was of particular interest to Saint Thomas Aquinas and to Catholicism, to whom it provided the basis for his social teaching. His influence is also strong on the social thought of Islam. Nowadays, Aristotle”s economic thought is also studied by those who want to moralize the economy. For a long time, Aristotle was credited with the Economics in the Middle Ages, the authenticity of which is in fact highly doubtful.

Thinking with little focus on economic analysis

Joseph Schumpeter was one of the first to question the existence in Aristotle”s thought of an economic analysis, i.e. an “intellectual effort… intended to understand economic phenomena”. His research led him to conclude that there was an analytical intention that did not lead to anything serious. Moreover, for him, the Stagirite would have treated the economy only by the small end of the spyglass and would have neglected the slavery which constituted then the base of the economy and the great maritime trade, the other key point of the Athenian power. So Aristotle restricts the field of economy to exchanges between free producers, which were then very marginal. In fact, the Stagirite only deals with “exchange relations that have the community as their framework”, which is moreover consistent with his politics.

For Atoll Fitzgibbons, Adam Smith”s plan was to replace Aristotelian philosophy, which he saw as a brake on freedom and economic growth, with an equally broad but more dynamic system.


Aristotle wrote three major works of rhetoric: the Poetics, the Rhetoric and the Topics.

According to Aristotle, rhetoric is above all a useful art. Defined as “the faculty of considering, for each question, what may be appropriate to persuade”, it is a “means of arguing, with the help of common notions and rational evidence, in order to make an audience admit ideas”. Its function is to communicate ideas in spite of the differences in language of the disciplines. Aristotle thus founds rhetoric as an oratory science independent of philosophy.

Each type of discourse corresponds to a series of techniques and a particular time. Judicial discourse requires the past, since the accusation or defense is based on facts that have already occurred. Deliberative discourse requires the future tense, since the future stakes and consequences of the decision are considered. Finally, the epidictic or demonstrative genre emphasizes amplification.

Aristotle defines the rules of rhetoric not only in the Rhetoric but also in books V and VI of the Organon. He bases it on logic, which he also codified. The section of the Topics defines the framework of argumentative possibilities between the parties, i.e. the rhetorical places. For Jean-Jacques Robrieux, “thus is traced, with Aristotle, the way of a rhetoric based on the logic of values”.

Besides a theory of rhetorical inference exposed in book I of the Rhetoric, Aristotle proposes in this same work a theory of passions (book II) and a theory of style (book III).

Poetics (tragedy and epic)

The last work of the Aristotelian corpus, and probably one of the best known by Aristotle, The Poetics deals with the “science of producing an object called a work of art”. While Aristotle considers poetry, painting, sculpture, music and dance to be arts, in his book he is mostly interested in tragedy and epic and, very anecdotally, in music. Aristotle mentions a future work on comedy which is among the lost works.

The role of the poet, in the Aristotelian sense, i.e. of the writer, is not so much to write verses as to represent a reality, actions; it is the theme of the mimêsis. However, the poet is not a historian-chronicler: “the role of the poet is to say not what really takes place, but what could take place in the order of the probable or the necessary it is for this reason that poetry is more philosophical and nobler than the chronicle: poetry treats of the general, the chronicle of the particular. The term general designates the type of thing that a certain category of men does or says likely or necessarily”. In tragedy, the story is more important than the characters.

In a story, “the peripatetic is the reversal of the action in the opposite direction”. Unity of action is undoubtedly the most important rule; it is obtained by the representation of a single action around which the whole tragedy is organized. Another major rule is the respect of verisimilitude: the story must present only necessary and plausible events; it must not include irrational or illogical elements, because this would break the adhesion of the public to the spectacle it is watching. If there are illogical elements in the story, they must be outside the narrative, as in Sophocles” Oedipus Rex.

The phenomenon of catharsis, or purification of the passions, linked to the tragedy, was the object of various interpretations. For Beck, “the emotions are purified analytically (as by a process of discernment exposed on the scene seen and producing a purification, a kind of abstraction, so that is also an intelligent pleasure “. In the “classical” interpretation, the sight of the bad or the painful moves away from this type of passions. The medical interpretation, as for it, considers that “the effect of the poem is to relieve physiologically the spectator”.

The Poetics, rediscovered in Europe from 1453 onwards, has been widely commented upon and invoked as an authority. The French 17th century wrongly attributed to it the rule of the three units in dramatic composition.

Brief presentation of the treaties

Aristotle devoted three small treatises to the question of sleep and dreaming: On Sleep and Wakefulness, On Dreams and On Divination in Sleep. These treatises extend the reflection of the treatise On the Soul, to which they sometimes refer indirectly, and aim at exploring psychological phenomena in relation to their physiological basis.

The Aristotelian conception of the dream

Like Xenophanes and Heraclitus, Aristotle rejects from the outset the ideas in force in his time that saw in the dream a divine apparition: “Neither can the dream be for the one who sees it, either a sign or a cause of the reality that comes after it; it is only a coincidence”.

He does not suspect the symbolism of the dream nor its narrative dimension, but remains fixed on the illusion it creates and its hallucinatory scope. In doing so, he departs from Plato”s conception in The Republic according to which the soul during sleep is freed from space and time and can set out to find the Truth. To the question of whether the dream is produced by the perceptive part of the soul or its intellectual part, Aristotle excludes both and asserts that it is the work of the imagination:

“Thus, during the night the inactivity of each of the particular senses, and the impotence to act where they are, bring back all those impressions, which were insensible during the vigil, to the very center of sensibility; and they become perfectly clear.”

The dreams thus make us relive experiences of the waking life, but under a reduced form because the perceptions carried out during the day left in the spirit traces, “a residue of feeling” (461 b). He attributes to the dream neither finality, nor function, nor significance, but sees it as an almost mechanical production. One should thus not attach importance to it.

To properly interpret dreams, you must be able to recognize similarities:

“Moreover, the most skilful interpreter of dreams is the one who knows best how to recognize their similarities, because the images of dreams are more or less like the representations of objects in water, as we have already said: when the movement of the liquid is violent, the exact representation does not occur, and the copy does not resemble the original at all.”

Freud, who comments on this passage, also sees in the games of resemblance “the first foundations of any dream construction”. Aristotle was also interested in lucid dreaming and gave the first written testimony to the fact that one can be conscious of dreaming while dreaming:

“If we feel that we are asleep, if we are aware of the perception that reveals the sensation of sleep, the appearance shows itself well; but there is something in us that says that it appears Coriscus, but that it is not there Coriscus; for often when we are asleep, there is something in the soul that tells us that what we see is only a dream.”


After his death, Aristotle was forgotten for at least two reasons. On the one hand, his pupil and successor, Theophrastus, did not bother to develop his teaching but preferred to devote himself to his own research on plants and on the notion of “prime mover”. On the other hand, Aristotle did not really found a school in the doctrinal sense of the term. Finally, Straton of Lampsacha, who succeeded Theophrastus, seems to have “turned away from many aspects of his founder”s teaching, and especially from his political teaching”. According to an anecdote reported by Strabo, the works of Aristotle and Theophrastus were left at the bottom of a cellar, forgotten by all, until they were discovered in the first century BC by the bibliophile Apellicon, who bought them. Sylla acquired Apellicon”s library and had it transported to Rome, where the grammarian Tyrannion undertook an edition and had a copy made for Andronicos of Rhodes, around 60 BC. The latter was the eleventh successor of Aristotle at the head of the Lyceum. It was he who established the “form and canon of Aristotle”s writings” and who “consecrated the way of philosophizing that prevailed among the Aristotelians until the end of Antiquity”.

In Roman times, Aristotelianism was not very popular, and was preferred to Epicureanism or Stoicism. Aristotle was nevertheless commented on by the Neoplatonist tradition and integrated into this philosophy, which attempted a synthesis between Plato, Aristotle and spiritual currents from the East. It is through the Neoplatonists, notably Plotinus, Porphyry and Simplicius, that Aristotelianism penetrates the first Christianity.

Aristotle”s physics had a definite influence on alchemy, particularly on Greco-Alexandrine alchemy. Indeed, alchemists such as Zosimus or Olympiodorus quoted him and used his concepts to think about the transmutation of metals (notably genus-species, substance-accident, act-power). However, philosophers who knew Aristotelianism well, such as Proclus and later Avicenna, refuted the theoretical possibility of the transmutation of metals, relying on a different interpretation of Aristotle. According to them, the fixity of species (types of metals) does not allow one metal to change into another.

Around the year 500, under the Ostrogothic king Theodoric the Great, the Latin philosopher Boethius translated the Logic and the Analytics and also left three books of commentaries on Aristotle. The High Western Middle Ages had access to Aristotle”s thought mainly through this work.

Influence on Byzantine thinkers

In the East, Greek Christian scribes played an important role in the preservation of Aristotle”s work by commenting on it and copying it (printing did not exist then). John Philopon was the first Greek Christian to comment extensively on Aristotle in the sixth century, followed in the early seventh century by Stephen of Alexandria. John Philopon is also known for his criticism of Aristotle”s notion of the eternity of the world. After a lapse of several centuries, towards the end of the eleventh century and the beginning of the twelfth century, Eustratius and Michael of Ephesus wrote new commentaries on Aristotle, apparently under the aegis of Anne Comnenus. A critical edition of these commentaries was published in Berlin in 23 volumes (1882-1909).

Penetration into the Muslim world

Greek texts were first translated into Syriac by Sergius of Reshaina and Severus Sebôkht during the 6th century, and then by James of Edessa and Athanasius of Balad in the following century. Following the persecution by Byzantium of the Jews and heretical Christians of Syria (Monophysites, Nestorians), they took refuge in the neighboring territories and bequeathed their libraries to the Muslim schools.

From the foundation of Baghdad in the eighth century, the Abbasid caliphate encouraged an intense translation activity, notably with Arabic-speaking Christian scholars such as Hunayn ibn Ishaq, followed later by Ibn Zura and Yahya ibn Adi, who translated the logico-philosophical corpus into Syriac and then into Arabic. Caliph Al-Mansur, who reigned from 754 to 775, and especially his successor Al-Ma”mūn, who reigned from 786 to 833, dedicated themselves to integrating Greek knowledge into Arab culture and sent emissaries to Byzantium and the great cities of the world in search of Aristotelian manuscripts.

To facilitate the establishment of a new technical vocabulary, Syrian-Arabic glossaries were elaborated from the 9th century onwards. On the other hand, works on mathematics or astronomy were often translated directly into Arabic, without Syriac intermediary. By the middle of the ninth century, “Arabic began to prevail over Syriac as a learned language in medical matters. These works were widely distributed throughout the Arab-Muslim world.

Aristotle left a deep impression on Islamic theology in its early days. Al-Fârâbî, Avicenna and Averroes wrote extensively on Aristotle. Their ideas influenced St. Thomas Aquinas and other Western Christian philosophers. Al-Kindi considered Aristotle to be the sole representative of philosophy and Averroes speaks of Aristotle as the example for every future philosopher. Medieval Muslim thinkers frequently present Aristotle as the “first master”. This title of “master” was later taken up by Western philosophers influenced by Islamic philosophy such as Dante.

Like the Greek philosophers, their Muslim counterparts consider Aristotle a dogmatic philosopher, the author of a closed system. They believe that Aristotle shares the essence of Plato”s philosophy. Some have gone so far as to lend Aristotle Neoplatonic ideas.

Western Middle Ages

During the High Middle Ages, in part of the West, only the works of Aristotle translated by Boethius at the end of Antiquity are known. But his works circulated in Muslim Spain where they were studied by Arab thinkers, notably Averroes. In another part of the West, Aristotle”s texts were known and copied by Greek monks, and translated by the Latins.

During the twelfth century renaissance, there was an important movement of translation of Arabic texts into Latin, sometimes into Castilian, but also into Hebrew with the family of Rabbis Ibn Tibbon. In addition to the works of Aristotle, Greek scientific works that had been translated into Arabic were translated as well as works of Muslim philosophers. This movement took off from 1100 onwards in various Spanish cities, notably in Toledo, where an important school of translators developed with Gerard of Cremona and Michael Scotus. Other translation centers were active in Palermo, Rome, Venice, Pisa, and Mont Saint-Michel.

However, in Sicily and in France, Aristotle”s texts are known directly from Greek. Indeed, Henri Aristippe, Albert the Great and Guillaume de Moerbeke, a close friend of Saint Thomas Aquinas, translated from ancient Greek.

In the 13th century, Aristotelian philosophy, revised by Thomas Aquinas, became the official doctrine of the Latin Church, despite some upheavals, such as the 1277 condemnation of a set of Aristotelian propositions by the bishop of Paris, Stephen Tempier. It also became the philosophical and scientific reference for all serious thinking, giving rise to scholasticism and Thomism.

St. Thomas Aquinas is fundamentally an Aristotelian even if his thought also draws from other sources. As with the Stagirite, in Thomas Aquinas philosophy includes practical science and theoretical science, which are themselves broken down into several fields. However, Thomas Aquinas makes certain twists to Aristotelian thought. On the one hand, he subordinates philosophy to theology, which is itself at the service of the knowledge of God. On the other hand, he integrates “all the Aristotelian sciences into a single, hierarchical order” which is itself subordinated to theology.

Cary Nederman accuses Thomas Aquinas of using Aristotle”s aristocratic tendencies to justify his own distaste for the mechanical arts, especially manual labor. Knight tempers this criticism. On the one hand, he notes that in his last, unfinished work, Thomas Aquinas places the ideal of nobility, dominant at the time, under the patronage of Aristotle and marks it with the Aristotelian seal of arete, excellence. Moreover, Thomas Aquinas, building on Aristotle”s thought, introduced the fight against poverty into the political field. Thus, his economic and social preoccupations can make him be considered more egalitarian than Aristotle. However, Thomas Aquinas, taking over from Aristotle the search for the common good, tends to turn Christianity away from the spiritual and towards the temporal domain, towards politics and the world. It thus distances it from the thought of Saint Augustine, whose theory of the two cities introduces a stronger distance between the temporal and the spiritual.


During the Renaissance (1348-1648), Aristotle”s work was widely studied in universities. His logic was taught everywhere and his philosophy of nature was widely disseminated, especially in the medical faculties of Bologna and Padua. One studies particularly the De anima II and III and the Physics. His metaphysics, as for it, is especially diffused in the Protestant universities. The teaching of his moral philosophy differs greatly from one institution to another. In general, ethics is much more studied than politics.

During this period, commentaries on Aristotle are very numerous. Richard Blum has counted 6,653 between 500 and 1650.

The Paduan Aristotelianism of the fifteenth and sixteenth centuries neglected the teleological aspect to focus, following Marsilio of Padua, on civic virtues such as loyalty to the state and its rulers. When Leonardo Bruni re-translated the Politics and Nicomachean Ethics, he was less concerned with conceptual problems than with the desire “to propose works written in excellent Latin that would allow his Florentine compatriots to imagine themselves paragons of Aristotelian virtue”. Following him, republicanism, according to Kelvin Knight, elaborates the notion of the sovereign state by referring to the Aristotelian idea of a self-sufficient political community. Individualistic republicanism, which an English-language author such as Machiavellian scholar John M. Najemy contrasts with corporatist republicanism, is marked by Aristotelian ethics and, like it, links “ethical excellence to good birth, good education, power and leisure”.

Martin Luther sees the Catholic Church as a Thomistic or Aristotelian Church and opposes the Stagirite on several points:

Luther”s successor, Philip Melanchthon, returned to Aristotle. However, for him, ethics does not aim at temporal happiness. It tends, on the contrary, to discipline the action of men so that they can act in conformity with the divine will. Ethics, in a word, supports the action of grace.

Birth of modern science and questioning of Aristotle

From 1600 onwards, Aristotle”s logic and his astronomy were questioned. Francis Bacon, one of the fathers of modern science and philosophy, challenged the abuse of references to Aristotle”s authority in his work On the Progress and Promotion of Knowledge (1605): “Knowledge derived from Aristotle, if removed from free examination, will not rise higher than the knowledge that Aristotle had. At the beginning of the 17th century, Galileo, who defended heliocentrism, came into conflict with the Catholic Church and with the majority of educated people who, following Aristotle, maintained the thesis of geocentrism. Despite Galileo”s condemnation, heliocentrism, in spite of everything, triumphed with Isaac Newton. For Alexandre Koyré, the transition from Aristotelian geocentrism to heliocentrism had two major consequences:

“a) the destruction of the world conceived as a finite and well-ordered whole, in which the spatial structure embodied a hierarchy of value and perfection, a world in which “above” the heavy and opaque earth, the center of the sublunary region of change and corruption, the celestial spheres of the imponderable, incorruptible and luminous stars “rose”…

Aristotle and philosophy from the 17th to the early 19th century

According to Alexandre Koyré, Descartes” world “is a rigorously uniform mathematical world, a world of reified geometry, of which our clear and distinct ideas give us an obvious and certain knowledge”. On the contrary, Aristotle”s world is “colored, multiform and provided with qualitative determinations”, it is “the world of our life and of our daily experience”.

In Aristotle”s view, men have principles within them that drive them to achieve their purpose. Christian Wolff, following Leibniz, transforms these various hierarchical tendencies “into a single narrative of a world and a universe providentially conceived for the benefit of the human race”, according to the principle of teleology. According to Pierre Aubenque, it was Leibniz who, despite Luther, ensured the continuity of the Aristotelian tradition in Germany.

Kant also transforms several Aristotelian concepts. First of all, going even further than Leibniz and Wolff, he proposes a “God as savior of virtue and guarantor of the complete good”, and, secondly, he modifies the meaning of practical reason. In Aristotle”s case, what is practical is linked to circumstances, is an adaptation of a general idea, whereas in Kant”s case, it is something universal that is not linked to circumstances. The two philosophers do not have either the same approach of the notion of concept: “A concept, for Kant, exists only in the mind of individuals. By contrast, a form, for Aristotle, is a real universal which is substantive in various substances from which it remains external, but which can be apprehended by the human mind “.

Hegel, following Wolff and Kant, further extends the field of teleology, which no longer concerns only human beings but also the system. Moreover, he moves from an atemporal universal to temporal and historical processes – a change that strongly marks modern teleologies. Hegel also has a different conception of individuals than Aristotle. According to him, the humans are parts of a universal whole which gives them identity, role and functions; the Stagirite, on the contrary, is more individualist, insists more on the centrality of the human beings seen as beings. Concerning the aesthetics, Hegel is situated halfway between the perception of work of art as technè that one finds in Aristotle, and that of fruit of the genius that one finds in Kant and the romantics.

Karl Marx is sometimes seen as partially Aristotelian because he has the idea of free action to realize the potential of human beings.

In the 19th century, there was a return to Aristotelian metaphysics, which began with Schelling and continued with Ravaisson, Trendelenburg and Brentano.

In the twentieth century Heidegger also returned to Aristotle. Kelvin Knight considers that the deconstruction of the philosophical “tradition” (which he understands above all as that of neo-Kantianism) carried out by this philosopher allows Leo Strauss and Hannah Arendt to rehabilitate Aristotle”s practical philosophy which, according to them, had been corrupted by science, natural law and the importance given to production. However, this return to Aristotle does not prevent a movement of distancing from Heidegger”s thought. Kelvin Knight, writes in this regard “these philosophers reject in part the interpretation that Heiddeger makes of Aristotle by refusing in particular to see, as he does, the Stagirite as the source of the theoretical tradition in philosophy”. In the same way, they refuse to use the word Dasein and prefer the Aristotelian terms of praxis and phronesis. In general, Kelvin Knight classifies Leo Strauss, Hannah Arendt and Hans-Georg Gadamer in a current that he describes as “practical neo-Aristotelian”. According to him, these philosophers would take up Heidegger”s thesis according to which Aristotle would place himself in the continuity of Plato and would insist on the fact that Aristotle conceives ethics as separate from metaphysics and technical knowledge. On the other hand, Gadamer and Arendt “assimilate the idea of aesthetic judgment in Kant”s third critique to what Aristotle calls phronesis”.

More recently, Alasdair MacIntyre has sought to reform the Aristotelian tradition in an anti-elitist way, thereby meeting the objections of the social liberals and Nietzscheans. Kelvin Knight describes this attempt as “revolutionary Aristotelianism”. In France, Pierre Aubenque insists on the forgetfulness, in the Aristotelian tradition, of the aporetic character of Aristotle”s work. This incompleteness of the Aristotelian thought explains, according to this philosopher, why Christianity and Islam so much appreciated the thought of the Stagirite. He writes about the Christian or Islamic interpretation: “because it had heard another Word, the silences of Aristotle appeared to him more welcoming to this Word than the competing word of Plato; it was easier to Christianize (or to Islamize) an Aristotle who remained below the religious option than to philosophize in the terms of a Platonism which was another religion”. The other way to fill Aristotle”s silences consists, according to Pierre Aubenque, in amplifying the scission by assuming the incompleteness of the thought; it is the way taken by the Neoplatonism. According to Aubenque”s interpretation, “the divinity of man is less the degradation of the divine in man than the infinite approximation of the divine by man”. In the XXth century, two philosophers proposed a logic competing with that of Aristotle: John Dewey with his book Logic: the theory of the inquiry and Bertrand Russell. Dewey claims to be the one who went the furthest in the novelty against Aristotle. He believes, in fact, that “it is not enough to extrapolate the Organon, as Bacon and Mill did, nor to adorn it with mathematical trappings, as Russell did” but that it must be founded on new foundations. What interests Dewey in logic is not so much to be sure of the true character of the thing by a deductive and formal reasoning, but, as the subtitle indicates, to establish a link between idea and action, based on both intuition and the study and verification of this idea.

Feminists, for their part, accuse Aristotle of being sexist and misogynistic. This accusation is based on the fact that Aristotle gives men an active role in procreation and that, in politics, he favors men.

In the 1960s and 1970s, some scholars looked at Arabic translations of letters that Aristotle is said to have written to Alexander the Great. In parts of one of these letters that Pierre Thillet considered, in 1972, to be relatively reliable, Aristotle no longer placed himself in the context of a city, but following the conquest of Persia by Alexander, in the context of a “state whose ethnic diversity could even tend to be erased by the massive deportations of the population. Let us note however that Pierre Carlier in 1982 in an article entitled Study on the alleged letter of Aristotle to Alexander transmitted by several Arabic manuscripts maintains that this letter is very posterior to the time of Aristotle.

Even so, more than 2,300 years after his death, Aristotle remains one of the most influential men the world has ever known. He worked on almost every field of human knowledge known in his time and helped open up many others. According to the philosopher Bryan Magee, “it is doubtful that any human being has known more than he did.

Aristotle in fiction

Comic book artist Sam Kieth made him one of the characters (along with Plato and Epicurus) in his comic book Epicurus the Sage.

General information about the work

We know that Aristotle wrote dialogues for the general public in the manner of Plato. Only rare fragments of them remain (Eudemus, The Philosophy, Of the Good, etc.). These dialogues represent Aristotle”s “exoteric discourses” (ἐξωτερικοὶ λόγοι), intended for a wide audience. Cicero did not hesitate to call his eloquence a “golden river” and to judge his books (now lost) better written than Plato”s.

The thirty-one treatises that remain to us come for the most part from lecture notes or writings intended for the specialized public of the Lyceum. Alongside the “exoteric discourses” (for the use of the public), we find oral lessons only, also called “acroamatic” notes, collections of lectures intended for advanced disciples.

Aristotle scholars wonder how the writings we know were assembled. Indeed, their organization sometimes seems haphazard and their style has little to do with what Cicero says.

About thirty of Aristotle”s works have been lost. Experts have questioned whether or not this loss distorts the understanding of Aristotle”s work. In his History of the Philosophy of the Greeks, Eduard Zeller answers in the negative:

“All the works in question belong to the last years of Aristotle”s life. If one day a happy discovery should enrich our knowledge of the chronological order of these writings, we should not expect the earliest work to take us back to a time when Aristotle was still working on his system. In all its parts, this one presents itself to us as a completed whole; nowhere do we see the architect at work.

It should be pointed out that this position dates from a time when “the image of a systematic Aristotle” was still dominant. Since the writings of Werner Jaeger, especially his 1923 book Aristotle, Foundations for a History of its Evolution, the thesis of the doctrinal unity of Aristotelian thought is no longer dominant.

Question of the interpretation of the work

The work we have is based on documents assembled in books in the first century B.C. by Andronicos of Rhodes without his having known the order envisaged by Aristotle nor “the ins and outs of the process, the motivations and the occasions of the writing”. The corpus at our disposal was thus written in the fourth century but edited in the first century BCE. For Pierre Aubenque, this gap of several centuries, coupled with the fact that Aristotle”s thought was forgotten during the same period, led to a strong dissociation between the man Aristotle and the philosophy known under his name. Also, the author”s intention being unknown, exegetes have been led to make hypotheses that have led to divergent lines of interpretation.

Until the end of the 19th century, Aristotle”s thought was considered to form a complete and coherent system, so that commentators “completed” Aristotle”s thought when necessary. According to Pierre Aubenque, the Greek commentators systematized Aristotle”s thought from neo-Platonism and “the scholastic commentators from a certain idea of the God of the Bible and his relationship to the world.

In 1923, Werner Jaeger, in a work entitled Aristotle: Foundations for a History of his Evolution, inaugurated a method of genetic interpretation that sees Aristotle”s philosophy “as a dynamic system of concepts” in evolution. He distinguishes three successive phases: the time of the Academy, the years of travel and finally the second stay in Athens. The first phase would be that of Platonic dogmatism (early works, the Ethics to Eudemus, Protrepticus). The second phase would be that of the birth of a critical Platonism and the blossoming of a transitional philosophy during which Aristotle corrected Platonism while taking up several Platonic themes: identification of theology and astronomy, the principle of the first immobile motor (an idea that originated in Plato”s Laws) and the notion of the soul of stars. Finally, the third phase would correspond to the second stay in Athens and would mark the apogee of the Aristotelian philosophy. During this third phase, Aristotle engages in empirical research and creates a new type of science based on investigations, description and observation of particular things. Jaeger thus proposes a systematic but evolving vision of Aristotle”s thought.

This way of seeing the evolution of Aristotle”s thought is contested. It has been criticized first by Ingemar Düring and then by Hans-Georg Gadamer, who believes that Jaeger”s analysis is based on what he considers contradictions. However, it is possible that what he perceives as contradictions is simply what in Aristotle”s thought is “complicated, nuanced, outside the framework of everyday common sense”. To overcome these defects, Pierre Aubenque prefers to start from the hypothesis according to which we are not sure that Aristotle “conceived a perfectly coherent system”. For him, Aristotle”s metaphysics would be aporetic and one should not look for a systematizing interpretation but, on the contrary, interpret the difficulties or aporias in order to proceed “to a methodical elucidation of the failure” of the systematization.

Catalog of Aristotle”s works

In Lives of the Philosophers (V, 21-27), Diogenes Laërce established a catalog of Aristotle”s works comprising 157 titles and which is still used as a reference even if many writings have been lost. It probably comes from the library of Alexandria. It is quite similar to that of the Onomatologos established by Hesychios of Miletus. The most complete catalog has been transmitted to us by two Arab authors, Ibn-el-Kifti in his Histoire des savants and Ibn-Abi-Oseibia in his Histoire des médecins célèbres.

The works are traditionally abbreviated by the initials of their Latin titles: thus P.N. for Petits traités d”histoire naturelle (Parva naturalia), G.A. for Génération des animaux. The numbers refer to the columns of the Bekker edition of the Berlin Academy (1831): thus, the History of Animals (H.A.) occupies the columns 486 a – 638 b.

The Logic (Organon)

Practical science (moral and political)

The productive science

Theoretical sciences

Zoological works

The small treaties


The most notable early editions of Aristotle are those of :



  1. Aristote
  2. Aristotle