cii. XXI,] GENESIS OF ATA N, INTELLECTUALLY. 297 



that, in point of intelligence and capacity for progress, the 

 real contrast is not between all mankind and other primates, 

 but between civilized and primeval man. 



Let us now consider some of the leading characteristics 

 of this gradual but increasingly rapid intellectual progress, 

 regarded as a growing correspondence between the human 

 mind and its environment. 



In the second chapter of our Prolegomena it was shown 

 that the highest kinds of scientific knowledge differ only in 

 degree from the lowest kinds of what is called ordinary 

 knowledge. In spite of their great differences in mental 

 capacity, it is obvious that the antelope who on hearing a 

 roar from the neighbouring thicket infers that it is high time 

 to run for his life, the Bushman who on seeing the torn 

 carcass of the antelope infers that a lion has recently been 

 present, and the astronomer who on witnessing certain unfore- 

 seen irregularities in the motions of Uranus infers that an 

 unknown planet is attracting it, perform one and all the same 

 kind of mental operation. In the three cases the processes 

 are fundamentally the same, though differing in complexity 

 according to the number and remoteness of the past and 

 present relations which are compared. In each case the 

 process is at bottom a grouping of objects and of relations 

 according to their likenesses and unlikenesses. It was 

 similarly shown that all knowledge is a classification of 

 experiences, and that every act of knowledge is an act of 

 classification ; that an act of inference, such as is involved 

 in simple cases of perception, is " the attributing to a body, in 

 consequence of some of its properties, all those properties by 

 virtue of which it is referred to a particular class " ; that the 

 " forming of a generalization is the putting together in one 

 class all those cases which present like relations " ; and that 

 " the drawing a deduction is essentially the perception that a 

 particular case belongs to a certain class of cases previously 

 generalized. So that, as ordinary classification is a grouping 



