48 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



Of course, the actual state of affairs, artificially modified 

 from what had been performed by the organism, must be 

 transmitted in some way to the latter, in order that its 

 future behaviour may correspond to this actual state. It 

 seems to me that it is from the possible or probable nature 

 of this transmission that an analytical discussion of our 

 problem must start. The instinctive motions concerned in 

 all sorts of constructions form a consecutive chain of single 

 performances, which normally seem to be called forth one 

 by the other, but which, as experiments show, may also 

 be called forth independently. So we again meet the 

 problematic question as to the " calling forth " of instinctive 

 motions, as to the instinctive stimulus. Normally the 

 whole sequence of a constructive instinct may go on as 

 follows. The elemental act a results in the state of construc- 

 tion A ; the next state of construction is B ; B is due to an 

 instinctive process b ; b may be set going only because a is 

 finished, but it also may be called forth by the existence of 

 A, which, of course, is something very different. The mere 

 fact of regulation, as we have described it, seems to show 

 that the second alternative meets the case : that it is the 

 existence of A, the constructive result of the first elemental 

 instinctive act, that is the stimulus of b, for in the case of 

 the regulation I goes on without a or after b itself has 

 already once taken place : without a, if the result of the in- 

 stinctive act was changed by the adding, and after a previous 

 b, if it was changed by the removing of anything. It is 

 here that we meet the problem of how the state of A as such 

 may be transmitted to the organism in order to determine 

 what is to go on, and it is clear that this is precisely the 

 problem of the nature of the stimulus calling forth b. 



