Aristotle (384-322 BC) was the most methodical mind of the ancient world. In fact, he was the founder of logic, which for him was an instrument of philosophy.
Aristotle's logic was based on the assumption of the existence of categories and meanings. The former correspond to normal things and the latter to their essence. Thus the acquisition of knowledge is based on meanings, which are being conceived under conditions that are in the senses.
The philosopher also distinguished knowledge into direct and indirect. The first is acquired insightfully while the second by observation, experience and subtraction.
Unlike Plato, Aristotle did not believe that ideas pre-existed. On the contrary, he believed that the human spirit has the ability to create meanings and with them to perceive reality.
As for the above-mentioned categories of normal things, these for Aristotle were the following ten, which he explained by describing a man, Korikos:
1) Substance (human)
2) Quantity (three bars)
3) Quality (white, educated)
4) Relationship (older)
5) Place (in the market)
6) Time (yesterday)
7) Position (sitting)
8) Condition (dressed)
9) Energy (cuts)
10) Suffering (cut)
Judging the Platonic theory of ideas, Aristotle considered as its disadvantage the division of reality into tangible and conceivable. So he preferred to deal with the perceptible reality and to look for the essence of beings within the specific objects.
Aristotle, knowing the views of the prosocratic natural philosophers and conducting physiognostic and biological research himself, came to the conclusion that things are specific combinations of matter and form, which he considered to be eternal and unchanging.
Extremely interesting is Aristotle's theory of man's ability to create poetry. In fact, the philosopher distinguished poetry on two different levels: The technological level of poetry aims at the creation of objects that complement nature. The artistic level aims at the interpretation of existing objects.
In Aristotle's natural philosophy, the teleological criterion is of particular interest. According to this, nature creates beings who aim at their self-realization. This is achieved through the optimal combination of form with matter. Therefore form is the purpose of creation.
At the level of natural philosophy, Aristotle was also interested in investigating what is happening in things. He therefore dealt with concepts of physics such as mass, space, time, motion, change, infinity, emptiness and continuum. He also founded biology and other related disciplines, such as phytology, zoology, entomology, embryology, ecology and animal psychology. He also suggested species classification methods and investigated the causes of sex differentiation, hereditary and acquired traits, polygon and oligogene, polycythemia and gestational age in animals, the spread of certain species and the effect of natural environment in the ethos of animals, their mental manifestations, their habits, weather effects on them and their diseases. Many of Aristotle's discoveries in the science of biology were discovered and accepted by lots of modern scientists, many of whom were unfamiliar with the work of the ancient philosopher.
As for the place of man in the animal kingdom, the great Macedonian philosopher acknowledged with arguments the undoubted superiority of the human species over other animals, although he accepted his biological relationship with them. As characteristics of human superiority he set the upright posture, the upright gait, the construction of the hand, the articulate speech and the conscious thinking. He also observed that the unique characteristics of man that contribute to his superiority are the ability to perceive the concept of time and measure it, the ability to remember himself, the ability to think about issues that concern him, the ability to choose, his laughter and his heart beats due to mental causes. Finally, without questioning the greater physical strength of many other animals compared to man, he observed his inexhaustible spiritual power, which allows him to achieve his goals.
Aristotle was also concerned with the issue of the soul. He dealt with the soul not only from a philosophical point of view but also from a biological, epistemological and moral point of view. He even expressed the view that "The soul is the first end in itself of a physical body that has life in it." In addition, he believed that the soul is for man what it is the form for matter. Finally, the philosopher distinguished three types of soul: the vegetative (of plants), the sensitive (of animals) and the rational (of humans).
On the issue of ethics, Aristotle, disagreeing with Plato and Socrates, argued that it is not based on the knowledge of good but on the practice of good, since it leads directly to happiness.
At the level of ethical philosophy, Aristotle dealt particularly with the subject of friendship, which he researched as a moral phenomenon. Friendship is about both the relationship between the casual passengers of a ship and the relationship between members of a family or between a person and himself.
At the level of political philosophy, Aristotle argued that a human being can be morally complete only in a society or otherwise that man is a "political animal". In fact, he believed that the goals of the individual and the whole are always identical in an organized society.
At the level of political philosophy, again,
Aristotle distinguished two different types of classification of the citizens
of a society. He first divided them into farmers, craftsmen and merchants. His
second categorization ranked them as rich, poor and middle class. The
philosopher thus stated that the relations between these social groups
determines the state.
Aristotle distinguished three typical types of regimes and three deviations from them. The first are the kingdom, the aristocracy and the democracy. The latter are tyranny, oligarchy and mob rule. Nevertheless, like Plato, Aristotle ultimately considered that there are essentially only two kinds of regimes: that which serves the good of society and that which serves only the good of the lords.
However, Aristotle supported the idea of a society where the middle class prevails and where everyone is equal before the law. Finally, the Macedonian philosopher was the first to support the principle of separation of powers and that of the majority.
As an epilogue it is noted that Aristotle was the teacher of Alexander the Great.
Finally, in modern Greece, the largest university is named after the great philosopher: It is the Aristotle University of Thessaloniki.
