But again, What is foresight of consequences?  It is a picture of a future state of things called up by knowledge of the present state of things, the future being viewed as standing to the present in the relation of effect to cause.  Again, we must seek a reduction to lower terms.  If the known present state of things is such that the act done will very certainly cause death, and the probability is a matter of common knowledge, one who does the act, [54] knowing the present state of things, is guilty of murder, and the law will not inquire whether he did actually foresee the consequences or not.  The test of foresight is not what this very criminal foresaw, but what a man of reasonable prudence would have foreseen.

On the other hand, there must be actual present knowledge of the present facts which make an act dangerous.  The act is not enough by itself.  An act, it is true, imports intention in a certain sense.  It is a muscular contraction, and something more.  A spasm is not an act.  The contraction of the muscles must be willed.  And as an adult who is master of himself foresees with mysterious accuracy the outward adjustment which will follow his inward effort, that adjustment may be said to be intended.  But the intent necessarily accompanying the act ends there.  Nothing would follow from the act except for the environment.  All acts, taken apart from their surrounding circumstances, are indifferent to the law.  For instance, to crook the forefinger with a certain force is the same act whether the trigger of a pistol is next to it or not.  It is only the surrounding circumstances of a pistol loaded and cocked, and of a human being in such relation to it, as to be manifestly likely to be hit, that make the act a wrong.  Hence, it is no sufficient foundation for liability, on any sound principle, that the proximate cause of loss was an act.

The reason for requiring an act is, that an act implies a choice, and that it is felt to be impolitic and unjust to make a man answerable for harm, unless he might have chosen otherwise.  But the choice must be made with a chance of contemplating the consequence complained of, or else it has no bearing on responsibility for that consequence. [55] If this were not true, a man might be held answerable for everything which would not have happened but for his choice at some past time.  For instance, for having in a fit fallen on a man, which he would not have done had he not chosen to come to the city where he was taken ill.

All foresight of the future, all choice with regard to any possible consequence of action, depends on what is known at the moment of choosing.  An act cannot be wrong, even when done under circumstances in which it will be hurtful, unless those circumstances are or ought to be known.  A fear of punishment for causing harm cannot work as a motive, unless the possibility of harm may be foreseen.  So far, then, as criminal liability is founded upon wrong-doing in any sense, and so far as the threats and punishments of the law are intended to deter men from bringing about various harmful results, they must be confined to cases where circumstances making the conduct dangerous were known.