It is clear that in proving the _à priority_ and the necessity of the causal law by the fact that the objective succession of changes is known to us only by means of that law, and that, in so far, causality is a condition for all experience, Kant fell into a very singular error, and one which is indeed so palpable, that the only way we can account for it is, by supposing him to have become so absorbed in the _à priori_ part of our knowledge, that he lost sight of what would have been evident to anyone else. The only correct demonstration of the _à priority_ of the causal law is given by me in § 21 of the present work. That _à priority_ finds its confirmation every moment in the infallible security with which we expect experience to tally with the causal law: that is to say, in the apodeictic certainty we ascribe to it, a certainty which differs from every other founded on induction--the certainty, for instance, of empirically known laws of Nature--in that we can conceive no exception to the causal law anywhere within the world of experience. We can, for instance, _conceive_ that in an exceptional case the law of gravitation might cease to act, but not that this could happen without a cause. Kant and Hume have fallen into opposite errors in their proofs. Hume asserts that all _consequence_ is mere _sequence_; whereas Kant affirms that all _sequence_ must necessarily be _consequence_. Pure Understanding, it is true, can only conceive _consequence_ (causal result), and is no more able to conceive mere _sequence_ than to conceive the difference between right and left, which, like sequence, is only to be grasped by means of pure Sensibility. Empirical knowledge of the following of events in Time is, indeed, just as possible as empirical knowledge of juxtaposition of things in Space (this Kant denies elsewhere), but _the way in which_ things follow _upon_ one another in general in Time can no more be explained, than the way in which one thing follows _from_ another (as the effect of a cause): the former knowledge is given and conditioned by pure Sensibility; the latter, by pure Understanding. But in asserting that knowledge of the objective succession of phenomena can only be attained by means of the causal law, Kant commits the same error with which he reproaches Leibnitz:[102] that of "intellectualising the forms of Sensibility."--My view of succession is the following one. We derive our knowledge of the bare _possibility_ of succession from the form of Time, which belongs to pure Sensibility. The succession of real objects, whose form is precisely Time, we know empirically, consequently as _actual_. But it is through the Understanding alone, by means of Causality, that we gain knowledge of the _necessity_ of a succession of two states: that is, of a change; and even the fact that we are able to conceive the necessity of a succession at all, proves already that the causal law is not known to us empirically, but given us _à priori_.