CHAP. IV.] DIVISION OP ABSTRACT PHYSICS. 135 



motion of systole and diastole, with regard to bodies placed 

 betwixt things advantageous and hurtful; 15. And lastly, 

 Motion couchiint, or a dread of motion, which is the cause of 

 many effects. And such are the simple motions that really 

 proceed out of tlie inward recesses of nature; and which 

 being complicated, continued, used alternately, moderated, 

 repeated, and variously combined, produce those compound 

 motions or results of motion we call generation, corruption, 

 increase, diminution, alteration, translation, mixtion, separa- 

 tion, and conversion. 



The measures of motions are an attendant on physics, as 

 showing the effects of quantity, distance, or the sphere of 

 activity, intension and remission, short and long continuance, 

 activity, dulness, and incitation. And these are the genuine 

 parts of abstract physics, which wholly consists, — 1. In the 

 schemes of matter; 2. Simple motions; 3. The results or 

 sums of motions; and, 4. The measures of motions. As for 

 voluntary motion in animals, — the motion in the action ot 

 the senses, the motions of the imagination, appetite, and will, 

 the motion of mind, the determination, and other intellec- 

 tual faculties, — they have their own proper doctrines under 

 which we range them, confining the whole of physics to 

 matter and efiicient, and assigning over forms and ends to 

 metaphysics. 



We must annex two remarkable appendages to physics, 

 with regard, rather to the manner, than the matter of inquiry; 

 viz., natural problems, and the opinions of the ancient philo- 

 sophers. The first is an appendage of nature at large, and 

 the other of nature united or summed up ; both relating to 

 a diligent kind of doubting, which is no contemptible part oi 

 knowledge. Now, problems contain particular doubts and 

 opinions, general ones, as to principles and structure. In the 

 books of Aristotle we have a noble example of problems, 

 deserving not only the praises but the imitation of posterity, 

 since new doubts are daily arising. But the utmost caution 

 is to be used in such an undertaking. The recording and 

 proposing of doubts has two advantages ; the one, as it 

 defends philosophy against errors, when that which is not 

 clear is neither judged nor asserted, lest error thus should 

 multiply error, but judgment is suspended upon it, and not 

 made positive : the other is, that doubts once registered jire 



