472 THE CAUSES OF THE XI 
brain do not exist at all, and you teach that all 
functions, intellectual, moral, and others, are the 
expression or the result, in the long run, of struc- 
tures, and of the molecular forces which they 
exert.” It is quite true that I do so. 
“Well, but,” I am told at once, somewhat 
triumphantly, “you say in the same breath that 
there is a great moral and intellectual chasm 
between man and the lower animals. How is 
this possible when you declare that moral and in- 
tellectual characteristics depend on structure, and 
yet tell us that there is no such gulf between the 
structure of man and that of the lower animals ?” 
I think that objection is based upon a miscon- 
ception of the real relations which exist between 
structure and function, between mechanism and 
work. Function is the expression of molecular 
forces and arrangements no doubt; but, does it 
follow from this, that variation in function so 
depends upon variation in structure that the former 
is always exactly proportioned to the latter? If 
there is no such relation, if the variation in func- 
tion which follows on a variation in structure may 
be enormously greater than the variation of the 
structure, then, you see, the objection falls to the 
ground. 
Take a couple of watches—made by the same 
maker, and as completely alike as possible; set 
them upon the table, and the function of each— 
which is its rate of going—will be performed in 
