PRESIDENTIAL ADDRESS. 675 
seems to afford the broadest outlook over our territory. It serves to check a 
tendency towards mere formalism on the one hand and to correct the not less 
baneful effects of a superficial teleology on the other. Both are real dangers, and 
we have all encountered examples of them. 
In rating highly the value of maintaining a physiological attitude of mind 
towards the phenomena presented by the vegetable kingdom, one is mainly 
influenced by the logical necessity which such a position carries with it of 
constantly attempting to analyse our problems, as far as may be possible, into 
their chemical and physical components. It seems to me that this is the only 
really profitable method that we can bring to bear on the difficulties that lie 
before us, because in using it we are constantly forced to consider the causes 
which have led to the final result. Of course I am well aware that to some 
minds the very attempt to apply such a method beyond a very limited range may 
appear futile, or at least premature. But the goal of all scientific inquiry lies in 
the ultimate ascertaining of cause and effect, and only with this knowledge can 
we hope to get control over the results, 
Ohemistry and physics each present to their followers problems far more 
elementary than those with which we have to grapple; but the explanation of the 
great advances which these two branches have made lies essentially in the fact 
that an analysis of the factors involved has enabled the investigator intelligently 
to interfere with, and so to control, the mode of presentation of the reacting 
bodies to each other. And our own special problems, whether we confine our- 
selves to the simpler ones, or whether we approach the obscurer matters of 
organisation, heredity, and the like, are assuredly susceptible of a similar method 
of treatment. We can never expect to get further than to be able to modify the 
mode of presentation to each other of the materials that interact to produce what 
we call the manifestations of life ; but the measure of our achievement will depend 
on the degree in which we are successful in accomplishing this. 
Indeed until we have analysed the nature of the reacting bodies, and also 
especially the particular conditions under which the reactions themselves are con- 
ducted, we are avoiding the first steps in the direction of ultimate success. At 
present, when we desire to know the taxonomic value of this or that character, 
we are perforce largely guided by purely empirical considerations. We find, for 
example, that a particular structure is very constant through a group of species 
otherwise closely resembling each other, and we rightly (but quite empirically) 
regard the possession of that character as a valuable indication of affinity within 
that alliance. But the very same feature in other groups may be highly variable, 
and lack all importance in them for systematic purposes. It may be, and very 
probably is, optimistic to look forward to the time when we shall know why 
the character is good in one, and worthless in another, alliance. But when we 
do, I am convinced that the reason will be found to lie in chemical and pbysical 
causes. We are very ignorant as yet of the details, but we can nevertheless even 
now form a fair guess at their general nature. 
In this connection I would venture to express the opinion that much real harm 
is done by the toleration of an uncritical habit of mind, all too common, as to the 
significance of structures which are regarded as adaptive responses to stimuli of 
various sorts. It is mot enough to explain the appearance of a structure on the 
ground of its utility ; properly speaking, such attempts, so far from providing any 
explanation, actually tend to bar the way of inquiry just where scientific investiga- 
tion ought to commence. 
That many of the responses to such stimuli are of a kind to render the 
organism ‘ adapted’ to its environment no one, of course, will dispute; but to put 
forwards the adaptedness as an explanation of the process is both unscientific and 
superficial, The size and the spherical shape of duckshot are admirably adapted to 
the purposes for which duckshot is used; but this affords no insight into the 
necessary sequence of cause and effect, which makes the melted lead assume the 
characters in question as it falls down the shot-tower. 
But many people still find consolation and satisfaction in an anthropomorphic 
and somewhat slipshod application of a kind of doctrine of free-will to matters 
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