After _physics_ we must come to _moral philosophy_; in which we are to consider the motions of the mind, namely, _appetite_, _aversion_, _love_, _benevolence_, _hope_, _fear_, _anger_, _emulation_, _envy_, _&c._; what causes they have, and of what they be causes. And the reason why these are to be considered after _physics_ is, that they have their causes in sense and imagination, which are the subject of _physical_ contemplation. Also the reason, why all these things are to be searched after in the order above-said, is, that physics cannot be understood, except we know first what motions are in the smallest parts of bodies; nor such motion of parts, till we know what it is that makes another body move; nor this, till we know what simple motion will effect. And because all appearance of things to sense is determined, and made to be of such and such quality and quantity by compounded motions, every one of which has a certain degree of velocity, and a certain and determined way; therefore, in the first place, we are to search out the ways of motion simply (in which geometry consists); next the ways of such generated motions as are manifest; and, lastly, the ways of internal and invisible motions (which is the enquiry of natural philosophers). And, therefore, they that study natural philosophy, study in vain, except they begin at geometry; and such writers or disputers thereof, as are ignorant of geometry, do but make their readers and hearers lose their time. [Sidenote: That method of civil and natural science, proceeding from sense to principles, is analytical; and again, that which begins at principles is synthetical.]