iv INTRODUCTION. 



the vulgar, andjmay be called the anecdotes^ or fecret hijlory^ of Nctturc, 

 But hiftory and philofophy are two things very different ; though, I 

 admit, that, without the knowledge of fads, it is impofTible to form 

 •any fyftem of natural philofophy that is not a mere dream, being no 

 other than the imaginations of men, in place of the wifdorn of God. 

 But nothing deferves the name of philofophy except what explains the 

 caufes and principles of things ; and, therefore, as the niaterial world 

 is all in motion, and every thing in it produced and preferved by mo- 

 tion, it is the chief bufinefs of natural philofophy to (how what is the 

 principle of this motion, by which all the operatipns of nature are car- 

 ried on. This principle is, according to my philofophy. Mind, which, 

 operating in Body, and direding its movements, is what I call Na^ 

 ture. To diflinguifh the different kinds of this Mind, according to its 

 different operations in bodies organized and unorganized, and to (how 

 how thofe operations differ from one another, belongs to the philojo' 

 phy of Nature : And, as it is impofhble to conceive that Mind 

 can do any thing without an end or purpofe, being either itfelf intel- 

 ligent, or diredled by intelligence, it is a principal part of this fcience, 

 and, I think, the mofl delightful part of it, to inveftigate final caufes, 

 and to fhow, if poffible, of what ufe every thing in the fyflem is, and 

 how conducive to the harmony and beauty of the whole. But fince, 

 as I have faid. Mind not only moves Body immediately, but by the in- 

 tervention of other bodies, that is, by mechanifm, it belongs to the 

 natural philofopher to difcover by what laws matter thus operates up- 

 on matter ; and with what force, and in what diredlion, bodies impel 

 one another ; and what relation the time bodies are in motion, their 

 velocity, and the fnace they go through, have to one another. This 

 is difcovered by a proper application oi- geometry to the motion of bo- 

 dies ; and, in this way, tuathematics are of fingular ufe, not only in the 

 arts of life, but in the philofophy of Nature. But, if a mathematician 

 goes farther, and irjquires concerning the principle of motion, and the 

 operations of Mind \n body, or feparated from Body, he goes out of 

 his fcience, and incroaches upon the province of the natural philofo- 



pher, 



