go SECTIONAL ADDRESSES 
suspended in the water may send out ‘ roots’ or holdfasts to regain 
contact with the bottom. 
Behaviour, whether of plants or animals, is thus to be regarded simply 
as one form of the general directive activity which is characteristic of the 
living organism. It holds no privileged position ; it does not require 
‘ mind ’ as an immaterial entity to explain it. 
I tried to show in the earlier part of this discourse that both ‘ matter ’ 
and ‘ mind ’ are abstract notions, of little real use in biology, and I main- 
tain here that the concept of ‘ organism ’ as I have attempted to define it - 
is a more concrete one, and a more useful one, for the practical purposes 
of biological research. 
If we accept this view of organism, which is to my mind a simple 
generalisation of fact, we escape or elude the difficulties of dualism ; we 
need no longer regard behaviour as either the mechanically determined 
outcome of the material organisation of the body, or the result of the 
activities of an immaterial mind or entelechy influencing in some utterly 
mysterious way the mechanical workings of the body. By taking as 
given and as fundamental the plain objective characteristics of the living 
and intact organism, by refusing to split it up into matter and mind, we 
avoid both materialism and its counterpart vitalism. 
This is, as I conceive it, the central position of the modern organismal 
theory—the substitution of the concept of organism for the concepts of 
matter and mind. The concept of organism, or more generally of 
organised system, may of course be applied right down through the in- 
organic realm, wherever organised unities are found. ‘Thus a molecule 
is an organised system, and so also is an atom. I do not, however, agree 
with those who think that all real unities, both organic and inorganic, are 
adequately characterised as ‘ systems.’ In certain most general character- 
istics an atom and a living organism agree, for both are systems or wholes. 
But the living organism has characteristics which are lacking in inorganic 
systems, and it can be adequately defined or characterised only by refer- 
ence to those peculiarities which we have just considered—the weaving 
together in one cyclical process of the master functions of maintenance, 
development and reproduction. ‘These distinguish it from any inorganic 
object or construction, from any inorganic system. Underlying these 
characteristics is the general directiveness of its activities, their constant 
drive towards a normal and specific end or completion. 
It will be noted that this organismal view makes no real distinction 
between life and mind, between vital activities and those which in 
immediate experience appear as mental or psychical activities. In this 
respect we hark back to a pre-Descartian mode of thought, and call 
Aristotle our master. 
Simple observation shows us that living animals exhibit activities 
which are obviously not, on the face of them, those of a mechanism. 
Many of their behaviour actions are strictly analogous to those which in 
immediate experience we should describe as psychological. Thus we 
see animals trying hard to achieve some aim or end—a salmon struggling 
to surmount a fall, for example, or a cat using all its skill to catch a bird. 
