Three Classes of Natural Philosopher

THOSE who have treated of natural pilosophy, may be nearly reduced to three classes. Of these some have been attributed to the several species of things, specific and occult qualities; on which, in a manner unknown, they make the operations of the several bodies to depend. The sum of the doctrine of the Schools derived from Aristotle and the Peripatetics is herein contained. They affirm that the several effects of the bodies arise from the particular natures of those bodies ari?e from the particular natures of tho?e bodies. But whence it is that bodies derive tho?e natures they don't tell us; and therefore they tell us no thing. And being entirely employed in giving names to things, and not in ?earching into things them?elves, we may lay that they have invented a philo?ophical way of ?peaking, but not that they have made known to us true philo?ophy.

Others therefore by laying a?ide that u?ele?s heap of words. thought to employ their pains to better purpo?e. The?e ?uppo?ed all matter homogeneous, and that the variety of forms which is ?een in bodies arifes from ?ome very plain and ?imple affections of the component particles. And by going on from ?imple things to tho?e which are more compounded they certainly proceed right; if they attribute no other properties to tho?e primary affections of the particles than Nature has done. But when they take a liberty of imagining at plea?ure unknown figures and magnitudes, and uncertain ?ituations and motion of the parts; and moreover of ?uppo?ing occult, freely pervading the pores of bodies, endued with an all-performing fubtilty, and agitated, with occult motions; they now run out into dreams and chimera's, and neglect the true con?titution of things; which certainly is not to be expected from fallacious conjectures, when we can ?carce reach it by the mo?t certain ob?ervations. Tho?e who fetch from by hypothe?es the foundation on which they build their ?peculations, may form indeed an ingenious romance, but a romance it will ?till be.

There is left then the third cla?s, which pro?e?s experimental philo?ophy. The?e indeed derive the cau?es of all things from the mo?t ?imple principles possible; but then they assume nothing as a principle, that is not proved by phenomena. They frame no hypotheses, nor receive them into philosophy otherwise than as queftions whose truth may be disputed. They proceed therefore in a two-fold method, fynthetical and analytical. From some select phænomena they deduce by analysis the forces of nature, and the more simple laws of forces; and from thence by fynthelis shew the constitution of the rest. This is that incomparably best way of philosophizing, which our renowned author most justly embraced before the rest; and thought alone worthy to be cultivated and adorned by his excellent labours. Of this he has given us a most illustrious example. by the explication of the System of the World, most happily deduced from the Theory of Gravity. That the virtue of gravity was found in all bodies, others suspected, or imagined before him; but he was the only and the first philosopher that could demonstrate it from appearances, and make it a solid foundation to the most noble speculations.

Those who name things, but give them no meaning, those who extrapolate big ideas from observed phenomena, but ideas subject to fancy, and those content to describe the simple basic principles and leave it at that.