Aristote says Stagirite, in Aristotelês Greek. Greek philosopher.

Principal founder of the Western intellectual tradition with Plato, his Master, the Greek philosopher Aristote developed a body of doctrines which embraces all the orders of the knowledge and the human activity of its time and which gave the model of all the future companies of systematization and classification of knowledge.  

Aristote, son of the doctor of king de Macédoine Amyntas II, goes to Athens as of 367, to remain there some twenty years disciple of Plato, studying with the Academy then teaching there until 347. It acquires during these years an encyclopedic culture, concerning all the aspects of the knowledge of its time. With the death of Plato, in 347, it is destined for Assos, in Asia Mineure, where a former student of Plato, Hermias d' Atarnée, has just seized the power.

Then it remains in Lesbos. In 343, Philippe II of Macedonia makes the tutor of his son of it, the future Alexandre the Large one, of which he will remain the friend until the murder of Callisthène, in 325. It is into 335 that, of return to Athens, it founds the College, or Péripatos (a peristyle where one walks while discussing and while arguing and who will leave his name to the Peripatetic school). It teaches a dozen years there. Constrained to flee Athens with the death of Alexandre in 323 pennies the charge of impiety, it dies in Chalcis into 322.

In the treaties gathered under the title of Organon (the methodical instrument), work provides also the foundations of the science of logic. Lastly, it includes certain fundamental investigations which relate to the first principles and the first causes. This research has as an aim the human practices and techniques, but also knowledge, in particular their rooting in the physical structures and metaphysics of nature as well as psychic and biological life. They also relate to reality in general: on the being, or on being, object of the discipline which will be called later metaphysical, or ontology.

Critic of the Platonism

The decisive stake of the thought of Aristote is to make understandable the movement and to become it. It is necessary for him for that to reject the theory of Plato, according to whom the Ideas immutable and are separated from the sensitive world. In addition to this transcendence of the Platonic Ideas, Aristote reproaches its Master for defining any knowledge as a simple ideal reflection of the real-world. However, which it is a question of making understandable in its own movement, it is the real-world itself. If the Ideas of Plato are in themselves understandable, they are, on the other hand, foreign in the sensitive world. However, if they are really separated from it, of two things one: or they do not have anything commun run with the world, and, therefore, remain to us inaccessible; or they still have something of commun run with the sensitive world (which could not be by itself understandable), but they need, like him, other ideas to be themselves understandable, and thus ad infinitum… It is thus necessary to cross short to this escape in the world of the Ideas, to undertake to directly know the reality of the concrete process of the world, i.e. nature itself, such as it is accessible to the human investigations.

Logic

Aristote distinguishes theoretic sciences (philosophy first, theology and ontology, mathematics, physics), practices (ethics and policy) and poetic (which treat production and techniques in various arts and trades). It is not easy to fix a place at logic in this classification: it is, in a sense, an art and a technique of the true speech, but its implications relating to the truth and the being make of it also a theoretical discipline, whose stake is metaphysical. The logic of Aristote is the doctrines of the logos (word which mean at the same time the word, the speech and the reason). It is exposed in the various treaties joined together under the name of Organon (the philosophical tool par excellence), which propose the thorough analysis of what constitutes the specific difference of the human being: word. Aristote indeed defines the Man as “the alive one who has the word”. As for the logical word, it is that which worries “to return proclamation what is”. So it is likely to receive a value of truth: truth or the forgery. It thus concerns the judgment, and not the feelings taken into account by the modes of the speech which Rhetoric or the Poetic one studies.  

The deductive reasoning
In the first two treaties of Organon, the Categories and interpretation, the likely word of truth is defined like the attribution of a predicate on a subject. Its structure thus comprises a noun stating that which one speaks (the subject) and an indicating verb what is known as subject (the predicate). In any judgment of the form “Socrate is mortal”, the union of the subject and of the predicate (“attribute”) is done by the copula: the verb “being”. The two terms thus joined together imply a significance characteristic of the verb “being”. These significances “to be it”, implied in the forms of preaching, are the categories.  

The Prime Ministers and the Second Analytical ones study the deductive reasoning, the “syllogism” and its multiple figures. This form of the reasoning consists in deducing, of two presumedly true proposals given (premises), a third proposal which is strictly the consequence, without other proposals being implied. For example, of the two premises: “All the men are mortals” (proposal major of the syllogism) and “Gold, Socrate is a man” (minor proposal) follows necessarily the conclusion: “Thus Socrate is mortal.” The possible forms of the syllogism (its “figures”) are studied systematically by the syllogistic one: it isolates the various types of proposals which can be implied there. This typology is established in particular according to the quantitative range - universal, particular or singular - proposals, but also according to the comprehension and of the extension of the concepts which there are prone or predicates. The syllogistic one proceeds, indeed, with a whole hierarchisation of the concepts in kinds, species and individuals: they is because all the men, constituting the mankind form part like the mortals (vaster class), and because the Socrate individual belongs to the mankind, that Socrate also belongs, necessarily, with the kind of the mortals, kind to which its species belongs.  

Principles of the reasoning
Presupposed fundamental which underlies the reasoning are also treated in the Analytical ones, which shows the need for going back until the principles and to the axioms presupposed in any deduction and demonstration. It is necessary for that to proceed to an operation of induction. But these principles themselves could be neither deduced nor shown: if not, it would be necessary to go up until the infinite one. Aristote puts forth the assumption then that the first principles - such as the non-contradiction, that all the other principles presuppose - are adopted in any reasoning by a “intuitive seizure”.  

The Topics - one of the last two treaties of Organon with the sophistical Refutations - study a prescientific form of thought. It is the discussion which tackles all the subjects indistinctly, without analyzing beforehand the basic principles which are clean for them. Thus, instead of being based on true and immediate premises like the scientific syllogism, the discussion refers to “commonplaces” (topoi), i.e. only probable premises which are allowed without examination by the interlocutors. Aristote sees a double interest in the analysis of the common opinions which are reported in the discussion. It makes it possible, firstly, to learn how to argue at the same time for and against an idea, and, by doing this, with better distinguishing the truth of the forgery.

Secondly, since the opinions, like the first principles of sciences, are born from the intuition, their study gives access to the apprehension of the scientific principles. In addition, the Topics propose, starting from the analysis of the premises of the discussion, a classification of the predicates. Indeed, according to his relationship with the subject, the predicate can indeed express the gasoline of the subject (it is the case of any definition), or one of its properties, or its kind or one of its accidental characteristics. They are thus there dialectical argumentations, where one does not show, but where one seeks simply what is true. As for the Refutations, Aristote gets busy there with the criticism of the fallacious argumentations of the sophists.  
 
Metaphysics

The logic of Aristote is not simply a formal instrument of scientific knowledge. It leads the meditation until the question “of the first principles and the first causes”, until the question of being it as being: What means being? What is, strictly speaking? The way then opens with “science to be it as being”, in other words with the “philosophy first”, which was called thereafter metaphysical, owing to the fact that the books which treated some found placed at Alexandria after Physics (méta your physika) in the catalog of works of Aristote established by Andronicos of Rhodos.  

Metaphysics - science of the first principles and the first causes - proposes to reach “the being as being” and “what is more being”. Research which she undertakes on these objects carries in germ two other disciplines: the ontology, whose object is the being as such, i.e. with the most general direction, and the theology, which represents a special ontology and either only general; its object is what raises to be it at the most point: God, i.e. being supreme to it.  

The Being
What is this thus, the being with the most general direction? The fundamental report of Aristote is that the being (or being it) says multiple ways. To realize it, it is necessary to consider the verb “being” and the ways in which it connects the predicate to the subject. The logical interpretation of the relation established by the verb “being” between these two terms of the proposals makes it possible to release the directions to be it, which are precisely the categories: the substance, quality, the quantity, the relation, the method, time, the place, the situation, the provision, the activity and the passivity, etc all these significances catégoriales to be it are added:  

• the being like the gasoline or the accident (in “Socrate is a man”, east expresses the gasoline, whereas in “Socrate sat”, east expresses the “accident”, because to be sitted is not an essential property of Socrate);  
• the being under the angle of truth or the forgery (what is false does not raise to be it with the same direction as what is true, because only the true one raises to be it strictly speaking);  
• the being like “being in power” or “being in act” (for example, the nipple is in a direction a oak, but only in power, while the oak is indeed, i.e. in act). Such are the four fundamental directions to be it: categories, gasoline or the accident, truth or the forgery, the act or power.  

Among these dimensions, it is the gasoline, the truth and the act which raise to be it with the cleanest direction of the term. In other words, the being strictly speaking is concrete: it refers to a thing, a living being, an individual, a person. Neither simple possibility nor potentiality, it recovers something which is indeed “in act”, “with work” (energeïa), or something which arrived to its achievement (entéléchie).  

Being
What is really (being it), with the most general direction, it is thus the real thing: the gasoline, or the individual substance which deploys its potentialities in act; it is the direction even of the entéléchie. It follows that being supreme to it (“God”) which represents the being at the most point must be at the same time gasoline and act (energy and entéléchie) at the most point. But, since it is entéléchie - perfection arrived to its achievement -, it also includes a finality (télos) which is achieved in him (teleology). Consequently, being supreme anything else tightens it towards only itself. It is what Aristote calls the “first engine not mû” of the Universe, of which the cosmic order harmonious and immutable (astronomical sky) is the visible figure, and who drives any thing, not mechanically but téléologiquement, and in an internal and immanent way in the world. God of Aristote is thus not external with the world; he by no means creates the world, which is eternal. God is rather it to what all the beings tend.

To understand the movement of the things of nature supposes the metaphysical distinction to be it in power and to be it in act. Because any change supposes that a “power” passes to the “act” (that something can become different, to move of a place with another, etc).  

The movement in nature
The movement thus supposes, in any change of state, the passage of virtual to reality, therefore of the power (dynamis) to the act (energeïa). The movement in itself is not simply the passage of the power to the kind of act which would be the perfect achievement and would thus carry out it once and for all. While being achieved, it is necessary that the movement remains unfinished, if it must be able to continue to be moving in its actualization. The movement is thus well the act of what is in power. The actualization of a power in a movement implies that something in him remains in power. The gasoline of the movement implies that something remains virtual there. This design makes physics of Aristote a dynamism.  

The movement is exerted in nature in four distinct forms:
- the displacement of a mobile of a point to another;
- the increase and reduction;
- the generation and corruption;
- the deterioration of a being.

These modes of the change suppose a relative incompletion of the things: a virtuality and a deprivation which the things tend to fill in order to join their natural place and to reach with plenitude to be to them in act, i.e. with the realization of their gasoline, their entéléchie.  

Matter and the form
This is why physics requires also the metaphysical distinction of the matter and the form. This distinction is worked out within the framework of an analysis of causality and finality.

By analogy with the productions of arts and trades, the natural beings concern four types of causes:
1) the material cause, or matter, indicates that whose thing is made;
2) the formal cause is the form which makes a thing ready to fulfill its function and thus puts it in accordance with its gasoline (an eye which its form would make inapt for the sight would not be an eye);
3) the efficient cause is it by what the thing is produced by working of a matter;
4) the final cause, finally, is it for what the thing is made, i.e. its function (without the sight, which is its function, the shape of the eye would not be understandable for us).

Cause formal and causes final play the crucial role here: because the matter, without the form, remains a virtuality and a power. The passage of the matter to the act calls a form to give place to the concrete thing. The “act” of a thing in is thus also the “form”, according to which the thing fulfills its finalized function (its end) and carries out its gasoline. Whereas products of art and of techniques have principle of their movement apart from them (in the artist or the craftsman, and the ends which they propose), the things of nature have it in themselves. It is the art which imitates nature, and not the reverse, even if one makes sometimes say the opposite to Aristote.   

Studying all the aspects of the movement in general, physics contains also the thorough study of the place, the vacuum, infinite, time (definite like the number of the movement), as well as the analysis of the need, the chance and the contingency.  

Aristotelian cosmology
The doctrines of the movement and the finality of nature raise the question of the ultimate term of the movements of the world. All virtualities of the things of nature pass there to the act to join their natural places there and to achieve there the full deployment of their gasoline (their entéléchie) according to a purpose similar (but nonidentical) to that with arts and techniques. The question is thus to know towards what the movements of the natural things tend. From where need for admitting the existence of a first engine not mû of the Universe, of a pure activity to which all the things would tend. This assumption makes it possible to consider the natural movement without explaining each finality by another finality, in other words without resorting to the regression ad infinitum. This topic of the pure act thus attaches physics to metaphysics; it is also the keystone of the system of the world, of the cosmology of Aristote. The treaties Of the sky and the generation and corruption present, respectively, the doctrines of cosmos and geocentric astronomy, and the theory of becoming specific to the sublunary world. This cosmology constitutes the base of the geocentric system of Ptolémée. With Platonic cosmology - that it will supplant in Occident towards the end of the Middle Ages -, it will work the image of the world until the astronomical revolution of Modern times.

Psychology and biology

Aristote expressed an insatiable curiosity for the observations concerning the living beings. From where extent and meticulousness of the studies that it devotes to them in the treaties known as biological. The key of all the phenomena of the life (organic), it is the psychology of its treaty Of the heart.  

The observation of the living beings and the study of their bodies methodically utilize the analogy in the comparative anatomy; it rests on the postulate, resulting from physics, a finality, or teleology of the nature, according to which the function determines the shape of the body. What is common to all the living beings like the internal principle of their movement, it is the heart (psyche). It is conceived as the shape - i.e. like the act, or like the entéléchie - of an organized body having the life in power. The heart is thus not of the same order as the body: it is neither a body nor part of the body. It is the passage to the act of the potentialities of a biologically organized natural body: the full blooming of virtualities of which it is able. Thus, the heart is with the animal (i.e. with the living being) what the sight is with the eye: it is the most completed function, in other words the entéléchie. This definition of the heart has as a consequence which heart without body it would not know to have there.

But the body of a living being is him also, like organization, a form fully completed with regard to the bodies and of the fabrics (of the matter) of which it is made up. The heart thus seems the most accomplished actualization of a whole hierarchy of forms resulting the depths and virtualities of physical nature; it thus remains to him immanent, with the way in which the function of a body is immanent with this body. The functions vegetative, sensitive and intellective of the heart are staged thus starting from the power and of the movement of nature itself, as a continuity of stages which carry out elementary life imperceptibly (“vegetative”) to the feeling, imagination, with the memory, finally with the thought - thus of form of life of the plant to those of the animal, human being and the divine one.

Ethics and policy

All the philosophy of the human things, i.e. ethics and the policy, depends on the distinction, in the human actions, between two orders of activity:  

1) the poïèsis, which is the production, or manufacture, of a work or a work, i.e. of a product external with the agent which produces it as with the activity producing it;  
 2) the activity practices strictly speaking, the praxis, which is the action, in itself judicious, and which is with itself its own end, i.e. the activity which coincides with the achievement even of that which acts. If any human action is made for some good - in particular for happiness -, there is only difficulty of agreeing on it in what happiness consists and on what is the sovereign well.  

If the activities which raise of arts and of the techniques (of the poïèsis) aim at a good, they suppose some architectonic art which organizes them and subordinates them according to the utility of the community: this art is not other than the policy. This one is given for end to produce the constitution (politeïa) city (polishes). The city is a political community, not only economic. It is not reduced to the community of the food and the satisfaction of the social needs; it is the community of the well-food, which gives itself for fine practice the only life which is worth to be lived for the human ones: happy life - i.e. virtuous and right - free and reasonable beings. The Policy of Aristote thus studies the various shapes of government which meet in the history of the cities, to determine those which are appropriate best for the human nature, as well as the way in which their Constitutions (monarchy, aristocracy, the republic while being three principal forms) are preserved or deteriorate (these deteriorations being, respectively, tyranny, oligarchy and the democracy).  

The virtues morals
It is the properly human analysis of the praxis (“the man is, known as Aristote, neither an animal nor a god”) which is the main idea of Aristotelian ethics. Anxious to return to morals the direction of the concrete situations and the various conditions of the human life, Aristote analyzes in its masterpiece, Ethics with Nicomaque, the multiple affections, provisions, characters and practices on bottom of what direction the various virtues come to take, as well intellectual as morals. Each virtue is an excellence consisting in “médiété”, i.e. right measurement between an excess and a defect. That of them which gives the tone and measurement to all the others in the concrete circumstances of the life, it is the practical wisdom of the reasonable man: the phronèsis, or prudence (of Latin prudentia). In accordance with this concrete wisdom, the human action reaches to perfection which is clean for him (its entéléchie): it becomes the human activity par excellence, that in which the man opens out his various potentialities. The balanced actualization of its faculties is seen crowned by the pleasure which comes to be added as by addition to the perfectly accomplished activity. This one can, at some, being carried to its roof in the contemplative life, when the wise one gives human figure to “the thought of the thought”. This ethics of the right measurement is not a morals of the mediocrity. She affirms that happiness is balance harmonious and humanly accessible from all the functions of the heart and the body, within a city right and in circumstances where freedom, wellbeing and friendship can reign.

The poetic one

Arts, which are opposed to the art of the life and science, are the subject of the treaty of the Poetic one, where they are defined like activities having for goal the imitation (mimesis) of the characters, passions and the actions. According to whether they imitate them by the colors and the forms or the voice and the sound, they are classified on a side in the visual arts and, other, in poetry. Heard in this special direction, poetry uses three means of expression: the rhythm, the language and air. Each one of them as their combinations indicate various poetic arts, which are five: dance (puts rhythm into); the imitation in prose, in particular mimes and dialogs Socratic (language); elegies and epic poetry (puts rhythm into and language); instrumental music (puts rhythm into, air); lyric poetry, the tragedy and the comedy (puts rhythm into, language, air). Owing to the fact that, according to Aristote, art does not imitate the sensitive world, as at Plato, but the world of the human spirit, the music, which causes most directly of the emotions, represents more the high degree of the mimesis.  

Aristotelian esthetics
The imitation is thus not synonymous with the reproduction. In the mental process by which one ends up recognizing what the work of art represents, it gets pleasure, accompanied by the sensual joy due to perception by the colors, melodies and rhythm. In fact, any artistic creation tends to the beauty. The final cause of the tragedy, which is in the center of Aristotelian esthetics, is to purge the feelings of pity and fear caused by the playwright. By the purging (katharsis) of the emotions, the tragedy does not make the spectators more emotive than they were it, as Plato claimed it, but it brings a certain relief to them. Far from being a simple entertainment, it delivers the spectator of pity and the fear which he tests following the example of the heroes of the tragedy.  

This esthetic theory, which inspired the most comments of its successors and who played a key role in the constitution of the French classicism, fits completely in the philosophy of Aristote: this one remains one of the most accomplished models of a thought which combines the direction of the major problems of metaphysics, of the philosophy of the nature and the theory of knowledge, to the most delicate direction of the measurement of what is human.