The principal causes are:—A bad ancestry (heredity), bad domestic and social conditions, alcoholism, imitation, and stress of circumstances.
Heredity.—Among unscientific people there are many extravagant theories held, some even affirming that from the moment of conception a child's character may be determined as criminal, as if character underlay habit instead of habit evolving character.
It is therefore necessary that we should endeavour to discover if possible how far the influence of heredity extends, and especially to disclose its powers as a factor influencing conduct. A man may be seen to have the same peculiar carriage and gait as his father; but to argue from that, that he will in obedience to a naturally transmitted impulse, follow in his father's footsteps as a thief or a forger is to step entirely out of the bounds of science. Gait and carriage belong to a different sphere altogether from morals and conduct. But let it be at once acknowledged that the morals and conduct of any given ancestry show a tendency to be reproduced in the posterity. The drunkard is the father of drunkards; the suicide is the father of suicides, and the parent's crime is repeated by the child. Not in all cases is this by any means a fact: but in a sufficient number to exclude the possibility of coincidence accounting for them all, and to demonstrate conclusively that some influence must be at work connecting the deeds of the progenitor with those of his offspring. What is this influence? Can it be at once declared to be the influence of heredity? The most usual way of determining this question is by the process of exclusion. If environment, education, imitation and other causes do not account for the phenomena, then heredity must. Heredity thus becomes a convenient name by which to denominate the insolvable. Sometimes the denomination is correct and sometimes incorrect, and very often, even when correct, it conveys a wrong impression. The impression being that the influence of heredity is altogether irresistible and also ineradicable.
Now, whatever the influence of heredity may be, it must be determined scientifically and not merely guessed at. Nor must the failure to find an adequate cause for a certain crime be a sufficient reason for accounting heredity as responsible. Heredity has limits to its range of influence as well as any other cause for crime, and it may be found that there are certain fears which it can never invade. For instance, one sphere wherein its influence is manifestly great, is in the structure of the nervous, osseous, muscular, circulatory and vascular systems. Again, what is more common than to find intellectual ability running in families? Ribot, in his work on heredity, gives long lists of the world's most famous poets, artists, musicians, statesmen and soldiers, all showing the tendency of ability, in these various directions, to be transmitted from one generation to another. Not always to the generation immediately succeeding, for sometimes these various qualities disappear in the son to reappear in the grandson or great-grandson. However, convincing the evidence for transmission in these cases may be, it gives no warrant whatever for the conclusion that heredity may exercise an influence upon the MORAL conduct of man.
Let it here be observed that the Moral Law is fundamental to all law. No laws in Nature ever contradict the Moral Law, but are always found acting in obedience to it. All the works of God are in accord with this Law; God is the Moral Governor of the Universe. Therefore whatever may hold good with all other laws, does not necessarily hold good with this Law. That a man should inherit his father's intellectual qualities is then no argument that he should also inherit his father's immorality. Nothing less will suffice than distinct evidence that he HAS inherited his father's immorality.
A further observation is necessary, and that is, that morality is not absolute but relative. Strictly speaking, no man is moral. God alone is absolutely moral. Nor can we compare the morality of one man with the average morality of mankind in general. To estimate a certain man's morality of conduct we must compare his conduct with the degree of the sense of responsibility which exists within him, and also his power of control over his conduct. The murderous act of a lunatic for instance is an immoral act, because we compare the act with morality in the abstract; but it would be a mistake to call the lunatic an immoral man, for the simple reason that he had no control over his conduct and was therefore not responsible for it.
Take the case of the drunkard. A certain drunken father has several drunken sons. The influence of environment, of education, or of imitation, we will suppose to be excluded. Is heredity the cause, and if so, has it invaded the moral sphere? The influence of the father's drunkenness is first made manifest in his own nervous system. The nerve centres become clogged and poisoned and fail to discharge their functions with the same healthy activity as formerly. The nervous system degenerates, and the consequence of this degeneracy is the production of that form of irritation within the system which we call the craving for drink, and which requires alcohol for its immediate satisfaction. The man will admit that he has no liking for the taste of drink; but declares that he is in a certain state of unsettlement which can only be overcome by the use of liquor. A temporary calm is induced, only to be followed by a more intense irritation or unsettlement afterwards, and thus a circle of cause and effect is at once described.
This is then the degenerate state of the father's nervous system. Now, it is undoubted that he may transmit this same degenerate nervous system to his offspring and thus as his children grow up it is not to be wondered at if the same craving for drink is to be found in them as was existing in their parent. The influence of heredity has been at work upon the nervous system. Has its influence been restricted to this system, or has it invaded the moral sphere? The children's conduct is immoral, for no amount of argument can determine drunkenness to be anything else: but are the children themselves immoral? They are not immoral so far as they are acting in obedience to an impulse which is irresistible. The drunkard who is himself responsible for his habit, is, strictly speaking, an alcoholic and is vicious and degraded. The drunkard who drinks in spite of himself is, strictly speaking, a dipsomaniac, and is diseased and insane. The alcoholic may become the dipsomaniac; but the child who is the victim of a transmitted taint is without doubt a dipsomaniac and not an alcoholic. He is insane. It may not be an incurable form of insanity; nor need it be a very acute form; but insanity it is, and therefore he cannot be called an immoral man because he drinks, although he is guilty of immoral conduct. Heredity has not invaded the moral sphere. It has given the man a diseased nervous system, which, while weakening his will, has not perverted it. Thus it is seen then that if any effort is to be made for the reform of the dipsomaniac, the direct influence of heredity must be overcome by a course of treatment which would be addressed to the nervous system. Treatment which shall draw out the alcoholic poison and which shall quicken and invigorate the nerve centres. When the influence of heredity is discovered to be restricted within these limits, the case of the hereditary dipsomaniac becomes far less hopeless than it appeared at first sight, and it is for this reason that the causes of crime should be thoroughly investigated. To moralise to the dipsomanic is but lost effort, one may as well abuse a driver for not stopping his bolting horses. Some reformatory schemes have trusted entirely to moral agencies, and their failure has been quoted as evidence that all such schemes are futile. But their failure has been due to an entirely wrong conception of the cause of crime. The primary cause is undoubtedly a reprobate will: but this cause is not found in every case. Where the consequences of the parent's conduct has been inherited we find not the primary, but a secondary cause, such as e.g. a diseased nervous system. Sometimes both the primary and the secondary causes exist side by side, and then treatment must be addressed to both the will and to the physical system. In fact whatever methods of treatment are employed, the moral temperament must not be neglected, for even if the will be not perverted, it is considerably weakened and needs strengthening.
The case of the sensualist is somewhat similar to that of the drunkard. Ribot quoting Prosper Lucas, gives the example of a "man cook, of great talent in his calling, has had all his life, and has still at the age of sixty years, a passion for women. To this he adds unnatural crime. One of his natural sons living apart from him does not even know his father, and though not yet quite nineteen, has from his childhood given all the signs of extreme lust, and strange to say, he, like his father, is equally addicted to either sex." (Ribot; Heredity p. 89.)
The fact that this son imitated his father's vices at an early age, is not sufficient in itself to assign the cause to heredity. Nor does the fact that he was separated from his father's influence or example, strengthen the assignment beyond dispute. The causes for such conduct are so common that very few men escape from their influence, and whosever does not resist them, falls and becomes a victim. But probably this was a case in which an inherited influence pressed itself so strongly upon him as to become irresistible. What, we ask was inherited? A perverted will? That is absolutely impossible. A perverted will is the outcome of a deliberate choice of evil when the choice of virtue is equally possible. A weakened will, or a will subject to heavy stress is a different thing. There must be some stress upon the will. What is it? It is a well known fact that the exercise of the members of our body results in a great facility of movement being attained. The pianist can, after long practice, execute rapid and complex performances of fingering, which in the early stages of education were absolutely impossible. It is because the nerve centres controlling the muscles employed have been brought to such a high state of activity that they operate almost independently of the will. The nerve centres controlling certain of our functions DO operate independently of the will. Breathing is an example, and although an effort of the will is required to correct bad breathing, yet when once the habit of correct breathing is established, the directing influence of the mind ceases, and the nerve centres discharge their functions automatically.