74 



HABIT AKD INTELLIGENCE. 



[chap. 



EelatioDS 

 presup- 

 posed in 

 associa- 

 tion. 



Percep- 

 tion. 



Percep- 

 tion may 

 have its 

 seat in the 

 sensory 

 ganglia. 



As the power of retaining the consciousness of a sen- 

 sation after the sensation itself has ceased is the germ 

 of memory, so the power of cognising simple relations 

 between sensations is the germ of thought. It is to be 

 observed that the cognition of simple relations is pre- 

 supposed in the formation of associations of ideas. Asso- 

 ciation by contiguity presupposes that the mind cognises 

 the relation of contiguity, whether in space or in time ; 

 and association by likeness, in the same way, presupposes 

 that the mind cognises the likeness. This is equally 

 true, whether I am right or not in believing that asso- 

 ciation by likeness is resolvable into association by 

 contiguity. 



The first stage in the development of thought is thus the 

 cognition of relations : the second is the perception of 

 things. I think that Berkeley has clearly proved the act of 

 perceiving things to be, not an immediate and simple act 

 of the mind, but an inference from data ; tlie data being 

 sensations, and the relations between sensations. It may be 

 advanced as an argument against this, that insects appear 

 to perceive, and yet they are without the cerebral hemi- 

 spheres, which in the Vertebrata are the organs of thought. 

 I reply that perception, though an inference, and as such 

 an act of thought, is not due to conscious thought, but to 

 unconscious, though sentient, organic intelligence. The 

 thought which I believe to have its seat in the cerebral 

 hemispheres is conscious thought, or, if it has become 

 unconscious, it has had its origin in consciousness. But 

 the sensory ganglia are perhaps the seat, not only of 

 sensation, but of the power of cognising likeness, suc- 

 cession, and the space-relation between sensations ; and 

 in insects, and possibly even in the Vertebrata, they 

 are the seat of perception also. In a future chapter I 

 shall have to treat the subject of perception with greater 

 fulness. 



In the development of thought, the next stage above 

 perception is that lower form of the reasoning power which 

 we have in common with animals. This may be defined 

 as merely reasoning from one object of sense to another, or 



