10 THE PRESIDENTIAL ADDRESS. 
world of commonsense and discovering the finer structure of physical 
nature, has at the same time disclosed certain fundamental features which 
it has in common with the organic world. Stuff-like entities have dis- 
appeared and have been replaced by space-time configurations, whose 
very nature depends on their principle of organisation. And this 
principle, which I have ventured to call holism, appears to be at bottom 
identical with that which pervades the organic structures of the world of 
life. The quantum and space-time have brought physics closer to biology. 
As I have pointed out, the quantum anticipates some of the fundamental 
characters of life, while space-time forms the physica] basis for organic 
evolution. Physics and biology are thus recognised as respectively 
simpler and more advanced forms of the same fundamental pattern in 
world-structure. 
The older mechanistic conception of nature, the picture of nature 
as consisting of fixed material particles, mechanically interacting with 
each other—already rudely shaken by the relativity theory—is now being 
modified by the quantum physics. The attack on mechanism, thus 
coming from physical science itself, is therefore all the more deadly. 
Even in physics, organisation is becoming more important than the 
somewhat nebulous entities which enter into matter. Interaction is 
more and more recognised to be not so much mechanical as organic or 
holistic, the whole in some respects dominating not only the functioning 
but the very existence of the entities forming it. The emergence of this 
organic view of nature from the domain of physics itself is thus a matter 
of first-rate importance, and must have very far-reaching repercussions 
for our eventual world-view. 
The nature of the organic whole is, however, much more clearly recog- 
nised in its proper sphere of biology, and especially in the rapidly 
advancing science of physiology. Here, too, the correct view has 
been much obscured by the invasion of mechanistic ideas from the physics 
of the nineteenth century. A crude materialism all but swamped biology 
for more than a generation. At the Belfast session of this Association in 
1874 a famous predecessor of mine in this Chair gave unrestrained 
expression to this materialistic creed. All that is passing, if not already 
past. It must be admitted that up to a point mechanism has been useful 
as a first approximation and fruitful as a convention for research purposes. 
But if even in physics it has lost its savour, a fortiort has it become out of 
place in biology. The partial truth of mechanism is always subtended by 
the deeper truth of organicity or holism. So far from biology being 
