The same truth is now known about crime; but the understanding and the application of it are just opening upon us. The old and still dominant thought is, as to cause, that a crime is caused by the inscrutable moral free will of the human being, doing or not doing the crime, just as it pleases; absolutely free in advance, at any moment of time, to choose or not to choose the criminal act, and therefore in itself the sole and ultimate cause of crime. As to treatment, there still are just two traditional measures --- jail, or a fine (for death is now employed in rare cases only). But modern science, here as in medicine, recognizes that crime also (like disease) has natural causes. It need not be asserted for one moment that crime is a disease. But it does have natural causes. And as to treatment, modern science recognizes that penal or remedial treatment cannot possibly be indiscriminate and machine- like, but must be adapted to the causes, and to the man as affected by those causes.