D.—ZOOLOGY 87 
resistance and extension, with location in time and space. By accepting 
this abstract definition or concept of matter, we substitute for the 
objective world of perception a symbolic or conceptual world of discrete 
material particles, which we may call the ‘ world of matter.’ This world 
of matter the materialist takes to be in some sense more real than the 
perceptual and colourful world from which he has derived it. Actually 
it is less real, less concrete. It is important to remember that the world 
which we perceive through the senses, with its shapes, colours, smells, 
tastes and so on, is not identical with the conceptual ‘ world of matter ’ ; 
we do not perceive ‘ matter’ at all, any more than we perceive mind ; 
we perceive things or relations or events. 
Complementary to this abstract material universe is the concept of 
mind as an inextended, immaterial, thinking entity, and this also is 
derived by abstraction from the data of immediate experience, and 
principally from the subjective aspect of experience. 
As applied to biology, this abstract dualism has saddled us with the 
theory that the organism is a machine, with the pale ghost of a mind 
hovering over its working, but not interfering. What chance is there for 
a real science of animal behaviour if this metaphysical view is accepted ? 
Obviously from the Descartian standpoint behaviour becomes a subject 
for the physiologist to study from his analytical point of view ; he must 
regard behaviour as the causally determined outcome of the working of 
the animal machine, under the influence of external and internal stimuli, 
and he must seek to determine the elementary physico-chemical processes 
out of which behaviour is built up. The physiologist as such can have 
nothing to do with mind, and hands over its study to the psychologist, 
who finds that he can know nothing directly about the minds of animals. 
Hence we get the state of affairs I alluded to at the beginning of this 
address—the study of animal behaviour split up between physiology and 
_ psychology, with no possibility of a connecting bridge. The scientific 
study of behaviour thus becomes divorced from natural history and 
ceases to take its rightful place as an integral part of zoology. 
Aristotle knew better than this; he regarded life and mind as con- 
tinuous one with another, and the basis of his zoological system was the 
form and activity of the animal as a whole. But then Aristotle was a 
first-rate field naturalist and observer. 
At this stage you may perhaps object that all this discussion of meta- 
physical notions is beside the mark and futile. You may say that as 
zoologists we are concerned only with facts and not with metaphysical 
theories. You may—dquite rightly—point out that in our practical re- 
searches we deal with the objective world of perception, and not with the 
abstract ‘ world of matter.’ 
But, unfortunately for us, these metaphysical notions which most of us 
have absorbed almost unconsciously from the older tradition of philo- 
sophical thought have influenced and continue to influence our aims and 
our methods in practical research. It is impossible to be an absolutely 
unbiased observer, an exact mirrog of the flux of events ; our conscious, 
and even more our unconscious, preconceptions lead us inevitably to 
