We may conveniently attack the problem by taking it up in the form in which Hume bequeathed it to modern science. As any careful reader of Hume must perceive, Hume’s whole doctrine of Causation is based on the assumption that the causal process is not continuous. Experience is supposed by him to come to us not in an unbroken stream, but in isolated separate pieces which we subsequently proceed to link together artificially by the notion of Causation. We are supposed to begin by observing the sequence of an event B on a previous distinct event A, and the problem of Causation thus becomes that of discovering the nature of the link by which the originally distinct A and B are connected in our scientific thought. In more technical language, Hume thought of the series of events as one in which every member has a next term, and this way of conceiving it has coloured the whole subsequent treatment of Causation by the inductive logicians who have commonly got their metaphysical doctrines from Hume. Now, recent Psychology, in deserting the old notion of the atomic sensation for that of the “stream of consciousness,” has completely destroyed the supposed empirical foundation for this Humian theory of the discontinuity of the course of events. The real problem for the inductive logician we can now see to be not to discover the link by which an originally separate A and B have got joined together in thought, but to find the source of the distinction we habitually draw within what comes to us as one continuous process between an earlier stage A which we call cause, and a later stage B which we call effect. We are not, however, concerned here with the psychological weakness of Hume’s doctrine, but with the logical difficulty to which it gives rise.