THE CRAYFISH MIND. 89 
while, in other cases, the act follows the sensation with- 
out one being aware of any other mental process ; and, 
in yet others, there is no consciousness even of the sensa- 
tion. As I wrote these last words, for example, I had 
not the slightest consciousness of any sensation of hold- 
ing or guiding the pen, although my fingers were caus- 
ing that instrument to perform exceedingly complicated 
movements. Moreover, experiments upon animals have 
proved that consciousness is wholly unnecessary to the 
carrying out of many of those combined movements by 
which the body is adjusted to varying external conditions. 
Under these circumstances, it is really quite an open 
question whether a crayfish has a mind or not; more- 
over, the problem is an absolutely insoluble one, inas- 
much as nothing short of being a crayfish would give us 
positive assurance that such an animal possesses con- 
sciousness ; and, finally, supposing the crayfish has a 
mind, that fact does not explain its acts, but only shows 
that, in the course of their accomplishment, they are 
accompanied by phenomena similar to those of which 
we are aware in ourselves, under like circumstances. 
So we may as well leave this question of the crayfish’s 
mind on one side for the present, and turn to a more 
profitable investigation, namely, that of the order and 
connexion of the physical phenomena which intervene 
between something which happens in the neighbourhood 
of the animal and that other something which responds 
to it, as an act of the crayfish. 
