36 PRESIDENT’S ADDRESS. 
a statement in terms of mechanics and physics could be clear and 
definite and true as far as it went, though it must necessarily be 
incomplete. 
And note that what we observe, in such understood cases, is an 
Interaction of Mind and Matter ; not Parallelism nor Epiphenomenalism 
nor anything strained or difficult, but a straightforward utilisation of the 
properties of matter and energy for purposes conceived in the mind, and 
executed by muscles guided by acts of will. 
But, it will be said, this is unfair, for we know that there is design 
in the Forth Bridge or the Nile Dam, we have seen the plans and under- 
stand the agencies at work: we know that it was conceived and guided 
by life and mind, it is unfair to quote this as though it could simulate 
an automatic process. 
Not at all, say the extreme school of biologists whom I am criticis- 
ing, or ought to say if they were consistent, there is nothing but 
Chemistry and Physics at work anywhere; and the mental activity 
apparently demonstrated by those structures is only an illusion, an 
epiphenomenon ; the laws of chemistry and physics are supreme, and 
they are sufficient to account for everything! 
Well, they account for things up to a point; they account in part 
for the colour of a sunset, for the majesty of a mountain peak, for the 
glory of animate existence. But do they account for everything com- 
pletely? Do they account for our own feeling of joy and exaltation, 
for our sense of beauty, for the manifest beauty existing throughout 
nature? Do not these things suggest something higher and nobler and 
more joyous, something for the sake of which all the struggle for 
existence goes on? 
Surely there must be a deeper meaning involved in natural objects. 
Orthodox explanations are only partial, though true as far as they go. 
When we examine each particoloured pinnule in a peacock’s tail, or 
hair in a zebra’s hide, and realise that the varying shades on each are so 
placed as to contribute to the general design and pattern, it becomes 
exceedingly difficult to explain how this organised co-operation of parts, 
this harmonious distribution of pigment cells, has come about on merely 
mechanical principles. It would be as easy to explain the sprouting 
of the cantilevers of the Forth Bridge from its piers, or the flocking of 
the stones of the Nile Dam by chemiotaxis. Flowers attract insects 
for fertilisation; and fruit tempts birds to eat it in order to carry 
seeds. But these explanations cannot he final. We have still to 
explain the insects. So much beauty cannot be necessary merely to 
attract their attention. We have further to explain this competitive 
striving towards life. Why do things struggle to exist? Surely the 
effort must have some significance, the development some aim. We 
thus reach the problem of Existence itself, and the meaning of 
Evolution. 
