Most liabilities in tort lie between these two extremes, and are founded on the infliction of harm which the defendant had a reasonable opportunity to avoid at the time of the acts or omissions which were its proximate cause. Rut as fast as specific rules are worked out in place of the [146] vague reference to the conduct of the average man, they range themselves alongside of other specific rules based on public policy, and the grounds from which they spring cease to be manifest. So that, as will be seen directly, rules which seem to lie outside of culpability in any sense have sometimes been referred to remote fault, while others which started from the general notion of negligence may with equal ease be referred to some extrinsic ground of policy. Apart from the extremes just mentioned, it is now easy to see how the point at which a man's conduct begins to be at his own peril is generally fixed. When the principle is understood on which that point is determined by the law of torts, we possess a common ground of classification, and a key to the whole subject, so far as tradition has not swerved the law from a consistent theory. It has been made pretty clear from what precedes, that I find that ground in knowledge of circumstances accompanying an act or conduct indifferent but for those circumstances. But it is worth remarking, before that criterion is discussed, that a possible common ground is reached at the preceding step in the descent from malice through intent and foresight. Foresight is a possible common denominator of wrongs at the two extremes of malice and negligence. The purpose of the law is to prevent or secure a man indemnity from harm at the hands of his neighbors, so far as consistent with other considerations which have been mentioned, and excepting, of course, such harm as it permits to be intentionally inflicted. When a man foresees that harm will result from his conduct, the principle which exonerates him from accident no longer applies, and he is liable. But, as has been shown, he is bound to foresee [147] whatever a prudent and intelligent man would have foreseen, and therefore he is liable for conduct from which such a man would have foreseen that harm was liable to follow.