ON THE REALITY OF THE SELF. 201 
physically feebler day by day, while he can daily do with less 
sleep and less exercise, less food and less excitement, as 
might be expected in one in whom the forces which make for 
life are already spent or fast waning, is it not the fact that 
his mental vigour remains comparatively unimpaired and that 
his judgment and his kindliness and his toleration are such 
that the younger gladly seek counsel from his maturer mind ? 
It is then absurd to say that the evolution of the mind ¢s the 
evolution of the nervous system, if it be meant that each 
mental phase,whether of increase or decrease, keeps time and 
pace with nervous growth or decay: for it is clear that the 
stages of the development of mind do not fully correspond 
with those of the development of the nervous mechanism any 
more than its gradual failure corresponds exactly with the 
failure of nervous energy. And thus the concave and convex 
theory, the subjective and objective aspect of one identical 
phenomenon or double-faced unity, does not appear to be 
exactly true to the facts. 
II. There is, however, much greater and more significant 
evidence to prove that the mind has laws of its own, which 
are not those of the physical mechanism. It appears that 
there are certain elements which necessarily enter into what 
we mean by an intelligent consciousness which have nothing 
like them im the nervous material mechanism. According 
to Kant, knowledge can only arise if two elements are 
contributed to its growth: on the one side there is a material 
factor, on the other side there is a formal or mental factor. 
The mind has laws of its own, in accordance with which it 
works, and these laws are not the laws of that material 
element which it assimilates and on which it feeds. So in 
the same way we can assert that consciousness Involves 
powers, faculties and elements which depend upon itself, and 
these cannot be accounted for by any enumeration of material 
mechanical processes. There are, for instance. certain mental 
products for which it would be difficult to find correspondent 
nervous processes. What nervous process could be held to 
correspond to the feelmg of moral obligation or duty, or the 
sentiment of justice, or the love of truth, or the higher 
esthetic feelings, or deliberate choice and acts of will in the 
higher sense? But there are humbler and more ordinary 
phenomena than these, which are exemplified in all our daily 
life, to which it is worth while to pay attention. 
1. We will begin with a very elementary element in the 
acquisition of knowle dge, viz., Attention. It is, of course, 
plain, that unless we pay attention to the phevomena that 
