286 THE DOCTRINE OF DESCENT. 
its application to man is a simple deduction from a 
general law, gained by the method of induction. As 
Goethe postulated the inter-maxillary bone in man 
even before he had seen or proved it, so must the doc- 
trine of Descent extend to man all its results and more 
or less plainly demonstrated laws. The deduction is 
effected by the accumulated observations of compara- 
tive anatomy, evolutionary history, and palzontology, 
checking and confirming one another. Thus, for all 
who are not satisfied with belief in miracle and sub- 
jection to the hypothesis of a revelation, nothing remains 
but the doctrine of Descent. To apply it to man is not 
more hazardous, but, on the contrary, as inherently neces- 
sary, as it is for us zoologists to make use of it in judg- 
ing some polype hitherto unknown, a star-fish or a mouse. 
This our adversaries deny. Man, they say, has qualitics 
which separate him absolutely from the animal, and, 
assuming the doctrine of Descent generally, preclude its 
applicability in this one case. To this assertion, so fre- 
quently to be heard, we will, in the first instance, oppose 
a general remark as to the apprehension of human 
nature. 
It is commonly overlooked that, quite regardless of 
the validity of the doctrine of Descent or even of its 
existence, there is a notable inconsistency in the idea of 
humanity. The philosophy of history has regarded 
mutability, which is, in fact, capability of progress, as 
the essence of human nature. But if any sort of in- 
separable dependence of the mind upon the body be 
admitted, as is the case with all but an extreme 
spiritualistic party, the progress of mental power in 
mankind was inconceivable without some parallel trans- 
