CHAP. III. | JERCEPTION DISTINCT FROM SENSE. 179 



held it, and thereupon recovers itself; perceives the sepa 

 ration of its continuity, and for a time resists it ; in tine, 

 perception is diffused through all nature. But air has such 

 an acute perception of heat and cold, as far exceeds the 

 human touch, which yet passes for the measure of heat and 

 cold. This doctrine, therefore, has two defects : one, in that 

 men have generally passed it over untouched, though a noble 

 subject ; the other, that they who did attend to it have gone 

 too far, attributed sense to all bodies, and made ifc almost a 

 sin to pluck a twig from a tree, lest the tree should groan, 

 like Polydorus in Virgil. h But they ought carefully to have 

 searched after the difference betwixt perception and sense ; 

 not only in comparing sensible with insensible things, in the 

 entire bodies thereof, as those of plants and animals, but 

 also to have observed in the sensible body itself, what should 

 be the cause that so many actions are performed without 

 any sense at all. Why the aliments are digested and dis 

 charged, the humours and juices carried up and down in the 

 body ; why the heart and pulse beat ; why the viscera act as 

 so many workshops, and each performs its respective office ; 

 yet all this, and much more, be done without sense. But 

 men have not yet sufficiently found of what nature the 

 action of sense is, and what k-nd of body, what continuance, 

 what repetitions of the impression are required to cause pain 

 or pleasure. Lastly, they seem totally ignorant of the dii- 

 ference between simple perception and sense, and how far 

 perception may be caused without sense. Nor is this a con 

 troversy about words, but a matter of great importance. 

 Wherefore let this doctrine be better examined, as a thing 

 of capital, and very extensive use : for the ignorance of some 

 ancient philosophers in this point, so far obscured the light 

 of reason, that they thought there was a soul indifferently 

 infused into all bodies ; nor did they conceive how motion 

 of election could be caused without sense, or sense exist 

 without a soul. 



That the form of light should not have been duly inquired 

 into, appears a strange oversight, especially as men have be 

 stowed so much pains upon perspective : for neither has this 

 art, nor Qthers. afforded any valuable discovery in the subject 



- Virg. JEneid, iii. 



