NEWTONIAN philosophy, the doctrine of the Universe, and particularly of the Heavenly bodies; their laws, affections, &c. as delivered by Sir Isaac Newton. The term Newtonian philosophy is ap plied very differently by different au thors. Some under this philosophy in clude all the Corpuscular philosophy, con sidered as it now stands corrected and reformed, by the discoveries and improve 'dents made in the several parts thereof by Sir Isaac Newton. In this sense it is that 'sGravesande calls his Elements of Physics, an Introduction to the Newto nian Philosophy; and In this sense, the Newtonian is the same with the new opposition to the Cartesian, the Peripatetic, and the ancient Corpus cular philosophy. Others, by Newtonian philosophy, mean the method or order which Sir Isaac observes in philosophiz ing, viz. the reasoning and drawing of conclusions directly from phenomena, ex clusive of all previous hypotheses ; the beginning from simple principles, deduc ing the first powers and laws of nature from a few select phemimena, and then applying those laws, &c. to account for other things ; and in this sense the New tOnian is the same with Experimental philosophy. Others again, by Newtonian philosophy, mean that wherein physical bodies are Considered mathematically, and where geometry and mechanics are appli ed to the solution of phenomena; in which sense the Newtonian is the same with the mechanical and mathematical philosophy. Others again, by Newtonian philosophy, understand that part of physical know ledge which Sirlseac Newton Ins handled, improved, and demonstrated, in his Prin cipia. And lastly, some, by Newtonian philosophy, mean the new principles which Sir Isaac has brought into philo sophy, the new system founded thereon, and the new solutions of phenomena thence deduced ; or that which charac terizes and distinguishes his philosophy from all others : and this is the sense, in which we shall chiefly consider it.
As to the history of this philosophy, we have but little to say : if was first made public in 1686, by the author, then a fel low of Trinity College, Cambridge ; and in the year 1713, republished with consi derable improvements. Several other
authors have since attempted to mike it plainer, by setting aside many of the more sublime mathematical researches, and substituting either more obvious rea sonings, or experiments in lieu thereof; particularly Mr. Whiston, in his Prelect. Phys. Mathem. isGravesande, in his Elm. and Inst. and the learned Comment of Le Seur and Jacquier upon Sir Isaac's Prin cipia.
The philosophy itself is laid down chiefly in the third book of the Princi pia ; the two preceding books being tak en up in preparing the way, and demon strating such principles of mathematics as have the most relation to philosophy : such are the, laws and conditions of pow ers : and these, to render them less dry .and geometrical, the author illustrates by scholia in philosophy, relating chiefly to the density and resistance Of bodies, the motion of light and sounds, a vacuum, &c. In the third book he proceeds to the philosophy itself ; and from the game principles deduces the structure of the universe and the powers of gravity, whereby bodies tend towards the Sun and planets; and from these powers, the motions of the planets and comets, the theory of the Moon and the tides. This book, which he calls De Mundi System ate, he tells us, was first written in the popular way ; but considering that such as are unacquainted with the said prinoi. ples would not conceive the force of the consequences, nor be induced to lay aside their ancient prejudices ; for this rea son, and to prevent the thing from being in continual dispute, he digested the sum of that book into propositions, in the mathematical manner, so as it might only come to be read by such as had first con sidered the principles ; not that it is ne cessary a man should master them all; many of them, even the first rate mathe maticians, Would find a difficulty in get ting over. It is enough to have read the definitions, laws of motion, and the three first sections of the first book ; after which, the author himself directs us to pass on to the book De Systemate Mundi.