ENERGEIA AND ENTELECHEIA – FIRST AND SECOND ACT. OPERARI SEQUITUR ESSE IN ARISTOTLE AND AQUINAS

Résumé

The term “act” is difficult to grasp since it is one of the simple notions which can be comprehended only by analogy. But it is also one of the most important concept in Aristotle and Aquinas. This paper attempts to have a closer look to the termin peripatetic perspective, especially dealing with the connection of the act with the demonstration of immortality of the soul. The first part discusses the two terms energeia and entelecheia, concentrating on the diff erence between them which can be seen in the text of Aristotle. Second part deals with the application of those two types of acts in philosophy of Aquinas, especially when he uses them to demonstrate that the existence of action per se must point at existence per se. It also shows that Aquinas seems to link those two terms with the concepts of first and second act, to cover the gap which occurred when two Greek terms (energeia and entelecheia) were rendered by one Latin term actus.