THE BIOLOGICAL ASPECT 307 
have any, is an emotion indicative of physical changes, not 
a cause of such changes. It does not enter into the chain of 
causation of their actions at all.” 
If the literal truth of this contention—the logical sound- 
ness of this conclusion—be admitted, it seems absurd to speak 
of the biological value of consciousness in behaviour or to 
discuss the importance of the réle that is played by the 
development of conscious situations in securing the biological 
end of racial preservation. 
Now, consciousness is regarded by an influential school of 
thinkers as a sort of deus ex machina, which, sitting enthroned, 
and crowned with a capital letter as Will, directs, like a being 
from another sphere, the doings of the body. It was against 
the doctrines of this school that Huxley took up arms. They 
do not concern us here. The will, or volition, as an under- 
lying cause, stands outside the pale of scientific inquiry. It 
belongs to the wide realm of metaphysics; its plea must be 
heard in another court. In this part of his contention Huxley 
was, we believe, unquestionably right from the scientific stand- 
point. Neither will, nor impulse, nor instinct, nor conscious- 
ness itself, should be introduced into any scientific description 
or explanation of phenomena as a cause of their existence or 
being, for as such it does not enter into the sequence of 
events; it is that which metaphysics claims as their raison d’étre 
—that which gives them being. Science in this matter should 
be frankly agnostic—neither affirming nor denying aught. 
This, of course, is not equivalent to saying that the agnostic 
position is the true end of human reason. That would only 
be so on the assumption that the problems of science are the 
only problems with which that reason can deal. To exclude 
metaphysics from science is not to exclude it from human 
thought. As a matter of fact such exclusion is neither possible 
nor reasonable. But to clearly distinguish the problems of 
science from those of metaphysics is absolutely necessary, if 
we are to prevent hopeless confusion of issues. 
In contending, however, against the introduction of meta- 
physical doctrines into the region of scientific explanation, 
