sense, and this conception, which people are so fond of using, just on account of the indefiniteness of the thought, is seen, if more closely considered, to be empty, false, and invalid. First of all, the reader must call to mind what causality really is, and to assist my exposition, see upon this subject § 20 of the introductory essay, also my prize-essay on the freedom of the will, chap. iii. p. 27 seq., and lastly the fourth chapter of the second book of this work. Causality is the law according to which the conditions or states of matter which appear determine their position in time. Causality has to do merely with conditions or states, indeed, properly, only with changes, and neither with matter as such, nor with permanence without change. Matter, as such, does not come under the law of causality, for it neither comes into being nor passes away; thus neither does the whole thing, as we commonly express ourselves, come under this law, but only the conditions or states of matter. Further, the law of causality has nothing to do with permanence, for where nothing changes there is no producing of effects and no causality, but a continuing quiet condition or state. But if, now, such a state is changed, then the new state is either again permanent or it is not, but immediately introduces a third state, and the necessity with which this happens is just the law of causality, which is a form of the principle of sufficient reason, and therefore cannot be further explained, because the principle of sufficient reason is the principle of all explanation and of all necessity. From this it is clear that cause and effect stand in intimate connection with, and necessary relation to, the course of time. Only because the state A. precedes in time the state B., and their succession is necessary and not accidental, i.e., no mere sequence but a consequence – only because of this is the state A. cause and the state B. effect. The conception reciprocity, however, contains this, that both are cause and both are effect of each other; but this really amounts to saying that each of the two is the
