Πwhat is the Principle of things? What are the building blocks of the universe? Can man know how everything began and if so, can he have a decisive influence on their evolution?
These are some of the questions that preoccupied the ancient Greek philosophers. Some of them talked about the 4 building blocks of Existence (Fire, Earth, Water, Air). Aristotle added a 5th, Aether, which he exalted to the position of the Quintet of the universe, even defining it as the material of the heavenly bodies.
Aether is different from the rest of the elements of nature as, for Aristotle, it always possesses those properties of the unchanging, divine and eternal essence.
Ether, or otherwise the fifth element, is that which "dwells" where the gods are, is not subject to the process of genesis or decay and is characterized by the lack of gravity. It thus moves perpetually and unceasingly in the region of the superlunar world, causing the circular motion in the heavenly bodies.
In this book, all the views of the great Stageritis on the quintessence of nature are developed, as well as the criticism he received from the philosophers of different schools of ancient Greece.