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advice as that given by tlie President of the Society to avoid as far as possible " such phrases as 
the relative influence of heredity and enviroiniient," when on his own showing he does not in 
the least appreciate the methods by which this relative influence is measured ? 
Then Major Darwin continues : " Surely what we want to know is how we can do most good — 
whether by attending to reforms intended to affect human surroundings, or to reforms intended 
to influence mankind through the agency of heredity. But does this ratio [that of the environ- 
mental and hereditary correlation] give us any sure indication of the relative amount of attention 
which should be paid to these two methods of i)rocedure ' " Our only reply can be that these 
correlations certainly do, and that as long as the President of the Eugenics Education Society 
fails to grasp their meaning, he is doing grave harm to the science of eugenics. 
We measure the change in the character of an individual which would be produced l)y a 
change of a like or an allied character in a parent, such change being one of which we have 
experience ; we measure the change which would be produced in the character of the individual 
by changes in the environment such as we have experience of, i.e. when we move the individual 
from a badly ventilated to a well ventilated house, from a back to back to a through house, from 
a low wage to a high wage, and so forth, and we find the resulting changes are of a wholly 
different order in these eases to what hapjjens when we change the physical characters, the 
health or habits which define the parents. It is on the basis of this that we assert that the relative 
strength of heredity is far greater than the strength of environment. To this reasoning, apart from 
such arguments as the above or those to be immediately dealt with, rejjly is only made by talk as to 
the impossibility of an individual surviving if you deprived him of his normal environment ! It 
would be just as reasonable to assert that everything must be due to heredity, because a race of 
supermen would breed supermen ! What the scientific eugenist has endeavoured to measure are 
the influences of such range of differences in envii'onraent as occur in everyday experience and 
are therefore producible from the political, economic and social standpoints, not the absence of 
all environment at all. But while this is recognised by some of the popular eugenic writers, they 
have apijroached the problem from another standpoint which indicates equally how little they 
grasp modern statistical theory. We admit, they say, that the environmental correlations may 
be of the order 'OS or '05 and the inheritance correlations of the order "50. But this is the 
correlation of one character in environment. You ought to take ten or twenty, and then you 
will have multiplied up environment to be more effective than heredity, for '03 x 20= 'SO. In the 
first place we may suggest that it would be just as reasonable, if the argument were a valid one 
to multiply up the favourable hereditary characters, to take weight, height, muscular activity, 
health, intelligence, caution, and many other desirable factors, and these not only in one parent 
but in brothers, sisters, aunts, uncles and grandparents and treat the cross-correlation of these 
with the character under discussion. But although every improvement in stock would reflect 
itself in improvement in offspring, correlations cannot be added together — any more than forces 
by simple arithmetical addition. You do not combine two hereditary correlations any more than 
two environmental correlations by mere addition. You must proceed by the combinatory jjrocess 
indicated at the commencement of this paper, which is one of course familiar to every trained 
statistician. 
Yet here is a statement which the Editor of the Eugenics Review admits to its pages without 
contradiction* : 
The point that we wish to make is this. In the face of so much ignorance concerning, not only 
heredity itself, but also its complement, the influence of environment, how can any one be justified in 
making sweeping generalisations with reference to these subjects ? 
Such generalisations, however, are made. It is said tliat we have a definite proof that inheritance is 
of far greater strength than environment. This argument takes the following shape. The correlations 
between parent and offspring for a number of features have been calculated, and the mean is found to 
* Vol. V. p. 219, in an article by A. M. Carr- Saunders. 
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