Quite unquestionably a great deals depends upon what is meant by causation, and still more upon the use made of the law of causation by theists. Thus we have seen it urged against Materialists that neural activity cannot be the equivalent of thought because they do not resemble each other. And in another direction we meet with the same idea in the assertion that the cause must be equal to the effect, by which it is apparently meant that the cause must be _similar_ to the effect, and that unless we can discern in the cause the same qualities manifested by the effect, we have not established the fact of causation at all. The complete and perfect answer to this last view is that the qualities manifest in an effect never are manifest in the cause, were it so it would be impossible to distinguish one from the other. The theist is, as is often the case, saying one thing and meaning another. What he says is that the cause must be adequate to the effect. There is no dispute here. But what he proceeds to argue is that the effect must be discernible in the cause, which is a different statement altogether. When he says that an effect cannot be greater than its cause, what he means is that an effect cannot be different from its cause, which is downright nonsense. He asks, How can that which has not life produce life? as though the question were on all fours with the necessity for a man to possess twenty shillings before he can give change for a sovereign. Of course, the reply to all this is that the factors which when combined produce an effect always "give" something of which when uncombined they show no trace. There is no trace; of sweetness in the constituents of sugar of lead, or of blueness in the constituents of blue vitriol. In not a single case, if we are to follow the logic of the theist, is there a cause adequate to produce an effect, if we are to follow the reasoning of some theists; in each case we should have to assume some occult agent as responsible for the result. In reality and in strict scientific truth, it is of the very essence of causation that there shall be present in the effect some quality or qualities that are not present in the cause. And all the confusion may be eliminated if there is borne in mind the simple and single consideration that in studying an effect it is the qualities of a combination with which we are properly concerned. And to expect to find in analysis that which is the product of synthesis is in the highest degree absurd.