It is clear that he regarded the Principia rather than the Opticks as his masterwork. Towards the end of his life, Newton 'gave one last effort to the Principia. On the history and importance of the third edition: Newton's universe, almost independent of the spiritual order, ushered in the age of rationalism, scientific determinism and the acceptance of a mechanistic view of nature' ( Printing and the Mind of Man 161). It was the final, irrevocable break with a medieval conception based on Greek and Roman cosmology and a scholastic system derived from the medieval interpretation of Aristotle. It was this grand conception that produced a general revolution in human thought, equalled perhaps only by that following Darwin's Origin of Species. The whole cosmos is composed of inter-connecting parts influencing each other according to these laws. The same laws of gravitation and motion rule everywhere for the first time a single mathematical law could explain the motion of objects on earth as well as the phenomena of the heavens.

With him the separation of natural and supernatural, of sublunar and superlunar worlds disappeared. Newton showed that the important and dramatic aspects of nature that were subject to the universal law of gravitation could be explained, in mathematical terms, within a single physical theory. The Principia provided the great synthesis of the cosmos, proving finally its physical unity. Copernicus, Galileo and Kepler had certainly shown the way but where they described the phenomena they observed, Newton explained the underlying universal laws.

'The Principia is generally described as the greatest work in the history of science. RARE 1726 THIRD EDITION OF NEWTON'S PRINCIPIA, THE LAST EDITION EDITED BY NEWTON AND THE BASIS FOR ALL SUBSEQUENT EDITIONS. Philosophiae Naturalis Principia Mathematica This applies especially to the theory of descriptive expressions (*14 and *30) and to the theory of classes and relations (*20 and *21).NEWTON, ISAAC.

Of the above three purposes, the first and third often compel us to adopt methods, definitions, and notations which are more complicated or more difficult than they would be if we had the second object alone in view. In the third place, the system is specially framed to solve the paradoxes which, in recent years, have troubled students of symbolic logic and the theory of aggregates it is believed that the theory of types, as set forth in what follows, leads both to the avoidance of contradictions, and to the detection of the precise fallacy which has given rise to them. In the second place, it is framed with a view to the perfectly precise expression, in its symbols, of mathematical propositions: to secure such expression, and to secure it in the simplest and most convenient notation possible, is the chief motive in the choice of topics.

In the first place, it aims at effecting the greatest possible analysis of the ideas with which it deals and of the processes by which it conducts demonstrations, and at diminishing to the utmost the number of the undefined ideas and undemonstrated propositions (called respectively primitive ideas and primitive propositions) from which it starts. T he mathematical logic which occupies Part I of the present work has been constructed under the guidance of three different purposes.

Principia mathematica