Natural Inheritance and Social Policy

Whf.n investigating any subject, the student of science should not hesitate long before endeavouring to frame some theory or general law by means of which all the facts known to him would be brought into harmonious relationship with each other. Such a provisional theory having been suggested, exceptional facts or out of the way occurrences will be of especial value in testing it; for either, being valid, it will be found to fit in with all new material as it comes to hand, or it must be modified to make it do so. The student of medicine is also, though for different reasons, especially interested in rare and previously unseen types of disease; for, in his ordinary practice, he knows that he may at any time have to advise on such cases. Medical men and men of science, in consequence, acquire the habit of attaching great importance to all that may be found in the dark and unexplored corners of their fields of investigation; and they are doubtless right in so doing. But when previously acquired knowledge has to be utilized in deciding broad questions concerning social policy, this attitude of mind is likely to be misleading. According to a well-known adage, hard cases make bad law; and, in like manner, exceptional facts should often be neglected when considering how mankind can be most effectivelv benefited. Exceptions are often difficult to recognise, even though they may be known to exist; and to endeavour to recognise them all would often put an end to all social progress. Moreover, laws which are framed so as to be applicable to all alike are apt, in consequence, to command