The rule that the law does, in general, determine liability by blameworthiness, is subject to the limitation that minute differences of character are not allowed for. The law considers, in other words, what would be blameworthy in the average man, the man of ordinary intelligence and prudence, and determines liability by that. If we fall below the level in those gifts, it is our misfortune; so much as that we must have at our peril, for the reasons just given. But he who is intelligent and prudent does not act at his peril, in theory of law. On the contrary, it is [109] only when he fails to exercise the foresight of which he is capable, or exercises it with evil intent, that he is answerable for the consequences. There are exceptions to the principle that every man is presumed to possess ordinary capacity to avoid harm to his neighbors, which illustrate the rule, and also the moral basis of liability in general. When a man has a distinct defect of such a nature that all can recognize it as making certain precautions impossible, he will not be held answerable for not taking them. A blind man is not required to see at his peril; and although he is, no doubt, bound to consider his infirmity in regulating his actions, yet if he properly finds himself in a certain situation, the neglect of precautions requiring eyesight would not prevent his recovering for an injury to himself, and, it may be presumed, would not make him liable for injuring another. So it is held that, in cases where he is the plaintiff, an infant of very tender years is only bound to take the precautions of which an infant is capable; the same principle may be cautiously applied where he is defendant. /1/ Insanity is a more difficult matter to deal with, and no general rule can be laid down about it. There is no doubt that in many cases a man may be insane, and yet perfectly capable of taking the precautions, and of being influenced by the motives, which the circumstances demand. But if insanity of a pronounced type exists, manifestly incapacitating the sufferer from complying with the rule which he has broken, good sense would require it to be admitted as an excuse. Taking the qualification last established in connection with the general proposition previously laid down, it will [110] now be assumed that, on the one hand, the law presumes or requires a man to possess ordinary capacity to avoid harming his neighbors, unless a clear and manifest incapacity be shown; but that, on the other, it does not in general hold him liable for unintentional injury, unless, possessing such capacity, he might and ought to have foreseen the danger, or, in other words, unless a man of ordinary intelligence and forethought would have been to blame for acting as he did. The next question is, whether this vague test is all that the law has to say upon the matter, and the same question in another form, by whom this test is to be applied.