Abstract

The article considers one of the most significant concepts in Aristotelian philosophy: the concept of substance and its interpretation in the works of existential Thomists. The emphasis is placed on the fact that the doctrine of substance is first and foremost to be considered in the context of the identification of the subject of scientific knowledge and in the context of the way of knowing this subject. In order to illustrate the epistemological realism, which, according to Thomists, inheres in Aristotle’s philosophy the article analyzes the previous philosophers’ views on the true subject of scientific knowledge. This subject is individual being, which forms the basis of philosophical understanding of things, as a subject of scientific knowledge. It should be noted that the method of constructing of Aristotle’s science general theory is finding reasons why something is just what it is from the viewpoint of necessity. Krąpiec believes that the way Aristotle comes to the formation of the four causes is related to the specificity of the question διὰ τί (why? because of what?). This analysis through causes allows us to understand that each single entity has a composite structure. Furthermore, Aristotle considers substance as a logical and grammatical category and as a main category in the ontological sense, as the mode of the initial being of things. Therefore, categories reflect the actual structure of things, namely the way of its existence on the essential and accidental levels. The very substance itself is recognizable only through the accidents associated with it and represents itself through them. However, the substance precedes its accidents in three meanings: ontological, definitive, and epistemological.