ch. I.] THE RELATIVITY OF KNOWLEDGE. 13 



been arranged into groups, so that when certain sensations 

 occur they may be recognized as belonging to such or such 

 a group. And in the adult, as our examples already cited 

 suffice to show us, an object is known just in so far as the 

 impressions which it produces upon lis can be assimilated 

 to previous impressions. Or if this is still not perfectly 

 clear, a brief citation from Mr. Spencer will make it clear. 

 "An animal hitherto unknown, though not referable to any 

 established species or genus, is yet recognized as belonging 

 to one of the larger divisions — mammals, birds, reptiles, or 

 fishes ; or should it be so anomalous that its alliance with 

 any of these is not determinable, it may yet be classed as 

 vertebrate or invertebrate ; or if it be one of those organisms 

 of which it is doubtful whether the animal or vegetal char- 

 acteristics predominate, it is still known as a living body ; 

 even should it be questioned whether it is organic, it remains 

 beyond question that it is a material object, and it is cognized 

 by being recognized as such. Whence it is manifest that a 

 thing is perfectly known only when it is in all respects like 

 certain things previously observed ; that in proportion to the 

 number of respects in which it is unlike them, is the extent 

 to which it is unknown ; and that hence when it has abso- 

 lutely no attribute in common with anything else, it must 

 be absolutely beyond the bounds of knowledge." x 



The bearing of all this upon our main thesis is so obvious 

 as to need but the briefest mention. Manifestly the First 

 Cause, the Infinite, the Absolute, can be known only by 

 being classified. We can conceive it at all only by conceiving 

 it as of such or such kind — as like this or that which we 

 have already conceived. There can be but one First Cause ; 

 and this, being uncaused, cannot be classified with any of 

 the multiplicity of things which are caused. The Infinite, 

 again, cannot be conceived as like the Finite ; nor can it be 

 classed with any other Infinite, since two Infinites, by mutu- 



* First Principles, p, 80. 



