Abstract

The subject matter of our considerations here is the concept of classical logic. The author begins with a brief etymological reflection and a presentation of some views ancient philosophers had (from Heraclitus to Plato) and inspired Aristotle’s and stoic discussion of logic. They brought about the first systems of formal logic and rich outlines of other branches of logic in their broad understanding, such as the methodology of sciences and semiotics. Aristotle’s logical discoveries (mainly syllogistic logic of assertoric propositions, syllogistic logic of modal propositions, and theory of scientific proof), and stoics’ discoveries (logic of propositions and semiotics) are the first, highly advanced approaches to classical logic. The later history of logic consisted mainly in the reception of those ancient achievements, or in their semantic enrichment