«ΕΙΔΟΣ»: from Plato to Aristotle

Background. The relevance of this study is related to the fact that many modern achievements of science are due to the speculative constructions that were formulated by representatives of classical ancient philosophy more than 2,400 years ago. It was Plato and Aristotle who laid the foundations of systematization and classification. Aristotle's work "Categories" represents the beginning of all scientific and theoretical knowledge, as it acts as a generalization of data. The principles he laid down have found their practical application in logic, theory of knowledge and epistemology, which makes their study especially important for the production of new scientific knowledge. Turning to the study of the main trends in the development of scientific knowledge in the 20th century, it is worth saying that the signs of the division of things proposed by Aristotle found their application in the works of both pre-revolutionary and Soviet researchers. This confirms the relevance of the problem under study. The purpose of the work is to define Aristotle's interpretation of Plato's concept of "είδος" and to consider the main ways of classifying genera and species of this concept. Materials and methods. To achieve this goal, general scientific methods were used: analysis, synthesis, deduction, classification. The source base for the research was the texts of key works of Aristotle: Metaphysics, Physics, Categories. Results. The nature of the "concept" as a form of thought remains largely Aristotelian, as something formed from the essential features of an object with permanence. Conclusions. The authors, after analyzing the evolution of the concept of "είδος" in the works of Plato and Aristotle, come to the conclusion that the existence of each "είδος" in Plato's opinion is transformed into a separate thing, according to Aristotle, and becomes an individual substance, "something". Universals, however, acquire an accidental character within the framework of his ideas. Their existence allows us to see hierarchy in genera and species, which makes it possible to classify genera and species, which enables us to talk about the systematization of the studied objects. According to Aristotle, the uni