168 SECTIONAL{ ADDRESSES. 
existent at' ali—is perhaps the most important of the fundamental 
questions which psychology has just now to answer, 
And the answer must be sought, not only by those psychologists 
who have wide training and all-round experience, but in, the full light 
of science as a whole. Part of my aim has been to lay stress on the 
solidarity of scientific inquiry. The psychologist must not work 
independently of the physiologist and the biologist, nor they inde- 
pendently of the chemist and the physicist. _No member of the 
brotherhood of science may ignore or contravene what has been 
established in other fields of research. Though there is more at any 
higher level of emergent evolution than there is in the lower, the more 
is never divorced from the less on which it is fourided. At the higher 
stage new modes of relation may obtain; but they are nowise discrepant 
with those which still obtain in the lower. And we must never interpret 
the lower in terms which belong to a higher emergent stage. That is 
false method in science. It is perhaps the cardinal principle of 
explanation in metaphysics; but in science it must be unreservedly 
condemned. 
We here touch the quick of the world-problem under the interpre- 
tation of science and explanation by metaphysics. Emergent evolution 
works upwards from materiality through life to consciousness which 
attains in man its highest reflective level. It accepts the ‘more’ at 
each stage as that which is given, and accepts it to the full and ungrudg- 
ingly. It urges that the ‘more’ of any given stage is dependent on, 
or implies, the ‘ less’ of the stages which are prior to it both logically 
and historically. It does not interpret the higher in terms of the lower ; 
for that would imply denial of the emergence of those new modes of 
natural relatedness which characterise the higher and make it what it 
is. Nor does it explain the lower in terms of the higher. It leaves that 
kind of explanation to metaphysics. If physical changes are explained 
in terms of life; if physiological changes are explained in terms of 
unreflective or perceptive cognition, or this is explained in terms of the 
reflective consciousness which is emergent in philosophical thought; if 
all that we know is explained as the expression of yet higher and more 
completely integrated Mind or Knowledge—that is, I believe, the dis- 
tinguishing mark of metaphysical as contrasted with scientific method. 
I do not deny its validity within its proper sphere. I do question its 
validity and its utility in science. But to distinguish is not to separate. 
It may well be that the methods are not antagonistic but complementary. 
None the less I seek to bring out as clearly as I can the position as I see 
it. Interpretation of the higher as founded on the lower (but fuller and 
richer in the advance of nature) is, I conceive, in accordance with the 
method of science; explanation of the lower in terms of that which is 
given only at a higher (and eventually the highest) stage—valid as it 
may be in metaphysics—must unreservedly be condemned in science. 
In dealing with a very difficult problem, in trying to dig down to 
foundations, in seeking to link up psychology with other branches 
of science under one consistent scheme of natural development, I 
have doubtless said many things which call for disagreement and 
