2t"]6 What are Animals and Plants ? 



physical science, but in that of philosophy, which is the 

 judge of physical science. 



Here, then, we may return, for a moment, to the con- 

 sideration of nature as the arena for the play of forces, 

 whether ' physical ' or ' vital.' 



It is, as we know, the scientific fashion of the day (and 

 a practically useful fashion) to regard the phenomena of 

 living beings as ' physical,' and to also consider the various 

 physical forces, heat, Hght, chemical affinity, etc., as so many 

 "niodes of ^motion. 



But when we raise ourselves above the horizon of physic;;! 

 science to the broader outlook of philosophy, can we thou 

 regard this practical reduction of all things to ' motion ' as 

 really an explanation ? 



We have freely conceded that ' vital force ' is a figment, 

 but what are we to say of heat, light, and motion also ? 

 Are they realities ? 



In fact, they are in themselves nothing more than 

 abstractions of the mind. There is no such thing as ' heat,' 

 or as ' motion ' ; though, of course, there are numberless 

 warm bodies of different temperatures, while as to the 

 quality ' moving,' nothing, so far as we know, is absolutely 

 at rest. But they are commonly spoken of as if they 

 were not mere qualities of bodies, but actual substances, 

 which may pass from one body into another and mutually 

 transform themselves. To explain the phenomena of living 

 beings, then, by ' mechanical motion,' however practical!}' 

 convenient for the investigation of physical science, is, from 

 the point of view of pure reason, a philosophical absurdity. 

 It is an attempt to explain them by a nonentity — a mental 

 abstraction from a certain quality found in things. More- 

 over, as living creatures make kno^vn to us various different 

 ' quahties,' to attempt to explain them all by different 

 quantities of one only quality is an attempt to extract the 



