Invariantive Mechanics

Mechanics is the science of motion of the bodies of the material universe. For centuries, this frame of our experience has been conceived in various manners.
Sometimes in a very complete and precise manner, in the sense that the universe i r , ~ c l u d e s both stars, the solar system and the bodies of the earthly experiments. It was the case of Aristotle's mechanics and also that of Ptolemy's; but each of these three worlds conserved its special motion laws. A proper and universal mechanical principle, unique for the whole universe, was formulated for the first time by Arhimede, who did not try to build a corresponding theory. I am thinking of the principle of the lever that was, however, a universal principle of equilibrium between action and reaction.
In modern times the idea of material identity among all the bodies of the universe made its way; it had a first great victory with the copernican theory. It also has been recorded as an indisputable truth in Leonardo's manuscripts, and it reached the final victory with Galilei's celestial discoveries.
The science. of natural motion began as early as people became convinced of a substantial .identity among the bodies of our universe. Limited, first, with Galilei, at the motion of the bodies under the strength of their weight here on the Earth, then with Newton for all motions on the Earth and in the planetary system, it has since aspired to include the whole universe. The latter being conceived as a unity realized by the motion of all its material bodies, in a system of interactions which maintain its stability.