The ordinary layman, though he may feel strongly interested in the problems of heredity and evolution, has seldom the leisure or the opportunity for the careful study of biological data, and he must therefore leave these to the specialists in scientific enquiry, but he is by no means precluded from using his own common-sense in drawing conclusions from the ordinary plain facts of life observable around him.  It is when we come to consider this most important question in its bearing upon the mental side of the human being that the ordinary layman feels himself to be no less competent to form an opinion than the trained man of science.

Is it possible, then, we ask, for the parent whose intellect has been developed through training in his lifetime to transmit to his children any portion of this acquired increment of mental capacity, or, putting the question in more concrete terms, is it possible for a parent to transmit to his offspring any part of that power to increase the size and quality of the brain which may be assumed to have resulted in his own case from mental exercise?  The question must not be misunderstood.  We do not ask whether clever parents do as a rule have clever children; what we want to know is whether the successive sharpening of the wits of generations of people does, or does not, eventually result in establishing a real and cumulative asset of mental capacity.

Seeing that universal education has only come about within the latter part of the last century it must be clear that the vast majority of the present generation of educated Europeans are descended from people who never had any of that education which so many people nowadays regard as essential to the development and growth of the intellectual powers.  But although education has only recently become, in various degrees, common to all white people, the light of learning has always been kept burning, however dimly at times, in certain places and circles, and it may, perhaps, be possible to find people to-day who are the descendants of those favoured few who have enjoyed, during many unbroken generations, the privilege of liberal education.  Now let us assume that there are at present a small number of such people in the forefront of the intellectual activity of the day, and then let us ask ourselves whether these leaders of thought who can claim long lineal descent from learned ancestors show any mental capacity over and above that which is displayed by those commoners who are also in the foremost ranks of thought and science, but who cannot lay claim to such continuous ancestral training.