The principle of causality—that every event is determined by previous events, and can (theoretically) be predicted when enough previous events are known—appears to apply just as much to human actions as to other events. It cannot be said that its application to human actions, or to any other phenomena, is wholly beyond doubt; but a doubt extending to the principle of causality must be so fundamental as to involve all science, all everyday knowledge, and everything, or almost everything, that we believe about the actual world. If causality is doubted, morals collapse, since a right action, as we have seen, is one of which the probable effects are the best possible, so that estimates of right and wrong necessarily presuppose that our actions can have effects, and therefore that the law of causality holds. In favour of the view that human actions alone are not the effects of causes, there appears to be no ground whatever except the sense of spontaneity. But the sense of spontaneity only affirms that we can do as we choose, and choose as we please, which no determinist denies; it cannot affirm that our choice is independent of all motives, and indeed introspection tends rather to show the opposite. It is said by the advocates of free-will that determinism destroys morals, since it shows that all our actions are inevitable, and that therefore they deserve neither praise nor blame. Let us consider how far, if at all, this is the case. (§ 25 ¶ 1)