Here A, B, C, is the causal succession of enduring states. The Greek letters represent a flow of other events which are really a determining element in the succession of A, B, C. And we understand at once how A, B, and C both alter and do not alter. But the Greek letters represent much more, which cannot be depicted. In the first place, at any given moment, there are an indefinite number of them; and, in the second place, they themselves are pieces of duration, placed in the same difficulty as were A, B, C. Coincident with each must be a succession of events, which the reader may try to represent in any character that he prefers. Only let him remember that these events must be divided indefinitely by the help of smaller ones. He must go on until he reaches parts that have no divisibility. And if we may suppose that he could reach them, he would find that causation had vanished with his success.
The dilemma, I think, can now be made plain. (a) Causation must be continuous. For suppose that it is not so. You would then be able to take a solid section from the flow of events, solid in the sense of containing no change. I do not merely mean that you could draw a line without breadth across the flow, and could find that this abstraction cut no alteration. I mean that you could take a slice off, and that this slice would have no change in it. But any such slice, being divisible, must have duration. If so, however, you would have your cause, enduring unchanged through a certain number of moments, and then suddenly changing. And this is clearly impossible, for what could have altered it? Not any other thing, for you have taken the whole course of events. And, again, not itself, for you have got itself already without any change. In short, if the cause can endure unchanged for any the very smallest piece of duration, then it must endure for ever. It cannot pass into the effect,
