Moral Inability means that ordinary motives are insufficient, but not all motives. The confirmed drunkard or thief has got into the stage of moral inability; the common motives that keep mankind sober and honest have failed. Yet there are motives that would succeed, if we could command them. Men may be sometimes cured of intemperance when the constitution is so susceptible that pain follows at once on indulgence. And so long as pleasure and pain, in fact and in prospect, operate upon the will, so long as the individual is in a state wherein motives operate, there may be moral weakness, but there is nothing more. In such cases, punishment may be properly employed as a corrective, and is likely to answer its end. This is the state termed accountability, or, with more correctness, PUNISHABILITY, for being accountable is merely an incident bound up with liability to punishment. Moral weakness is a matter of a degree, and in its lowest grades shades into insanity, the state wherein motives have lost their usual power—when pleasure and pain cease to be apprehended by the mind in their proper character. At this point, punishment is unavailing; the moral inability has passed into something like physical inability; the loss of self-control is as complete as if the muscles were paralysed.
In the plea of insanity, entered on behalf of any one charged with crime, the business of the jury is to ascertain whether the accused is under the operation of the usual motives—whether pain in prospect has a deterring effect on the conduct. If a man is as ready to jump out of the window as to walk downstairs, of course he is not a moral agent; but so long as he observes, of his own accord, the usual precautions against harm to himself, he is to be punished for his misdeeds.
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These various questions respecting the Will, if stripped of unsuitable phraseology, are not very difficult questions. They are about as easy to comprehend as the air-pump, the law of refraction of light, or the atomic theory of chemistry. Distort them by inapposite metaphors, view them in perplexing attitudes, and you may make them more abstruse than the hardest proposition of the “Principia”. What is far worse, by involving a simple fact in inextricable contradictions, they have led people gravely to recognise self-contradiction as the natural and the proper condition of a certain class of questions. Consistency is very well so far, and for the humbler matters of every-day life, but there is a higher and a sacred region where it does not hold; where the principles are to be received all the more readily that they land us in contradictions. In ordinary matters, inconsistency is the test of falsehood; in transcendental subjects, it is accounted the badge of truth.
[Footnote 1: Fortnightly Review, August, 1868.]