324 MENTAL EVOLUTION IN ANIMALS. 



Such, then. I conceive to be the first or most rudimentary 

 stage of inference, where, in virtue of constant association, 

 the act is organically bound up with a sensuous perception, 

 so as in fact to constitute an integral part of such perception, 

 and therefore to be precluded from ever emerging into con- 

 sciousness as a separate act of mind. The next stage in the 

 process of inference I take to be the one which Mr. Spencer 

 regards as the earliest stage. This, in his words, is "that 

 reasoning through which the great mass of surrounding co- 

 existences and sequences are known."* That is to say, when 

 habitually co-existing groups of external objects, attributes, 

 and relations recognized become too numerous and too com- 

 plex to be all recognized simultaneously, or when the first in 

 a series of habitually successive groups occurs, the unper- 

 ceived objects, attributes, or relations are inferred. For 

 instance, if a sportsman while shooting woodcock in cover 

 sees a bird about the size and colour of a woodcock get up 

 and fly through the foliage, not having time to see more than 

 that it is a bird of such a size and colour, he immediately 

 supplies by inference the other qualities of a woodcock, and 

 is afterwards disgusted to find that he has shot a thrush. I 

 have done so myself, and could hardly believe that the thrush 

 was the bird I had fired at, so complete was my mental sup- 

 plement to my visual perception. And, without waiting to 

 give illustrations, it is evident that the same principles apply 

 to the case of habitual sequences. 



The second stage of inference, then, is reached when, 

 owing to a constant association of objects, qualities, or rela- 

 tions in the environment, a correspondingly constant associa- 

 tion of ideas is produced in the mind, such that when some 

 members of the external group are perceived, the other 

 members of it are inferred. Inference at this stage resembles 

 inference at the earlier staire which we have considered in 

 one respect, and differs from it in another. The resemblance 

 consists in the act of inference being too rapid to admit of its 



tainly could not mean that they pressed upon or resisted his eyes .... 

 He could mean no more than that they were close upon his eyes, or to speak 

 more properly, perhaps, that they were in his eyes. A deaf man, who was 

 made all at once to hear, might in the same manner naturally enough say, 

 that the sounds which he heard touched his ears, meaning that he felt them 

 as close upon his ears, or, to speak perhaps more properly, as in his ears." 

 (Essay on External Senses.) 



* Principles of Psychology, vol. i, p. 438. 



