are not purely formal at all, but, if I may use the expression, simply loaded with content. This is clear immediately when we think of what I had to say, for instance, about intuitive space in the first two lectures. Space, time and the categories are spoken of as "pure forms" in Kant's philosophy, but they are used as if they were a strange mixture of form and content. There is no such mixture, of course, and as soon as one realises that only the Logical deserves to be called pure Form, one will easily get rid of the confusion which seems to give some plausibility to Kant's explanation of the supposed possibilities of synthetic judgments a priori.
Kant drew the line between the a priori and the a posteriori in the wrong place, and consequently the line between form and content — which he rightly felt, must coincide with the former line — was drawn in the same wrong place. In this way he obtained a region between this line and the line separating the synthetic propositions from the analytic ones — it was the region of his synthetic judgments a priori. But as a matter of fact there is no place for them, as the two borders of that region coincide and leave no space between them: there is no a priori except in tautology, and there is nothing synthetic, no real knowledge, except on the side of the a posteriori.
All knowledge is a posteriori, is beset on experience. It can be known to be true only for that experience on which it is based. A proposition about a future fact, or even about a past fact, or about "all" facts of a certain kind (so-called "grand complications"), must in a way, be regarded as hypotheses. The transition from true propositions to new propositions which are not known to be true but are expected to be so, is called induction. All I want to say about it here, is, that an induction is certainly not a logical process. No validity cannot be proved. It cannot even be proved that a proposition informed by induction will be probably true, whatever the degree of probability may be supposed to be. Logical inference as we have seen, is a transformation of an expression into an equivalent one of a different form, but the new proposition, since it really expresses something new, is surely not just a different form of the old proposition from which it is derived by induction. Therefore it is forever impossible to justify induction logically.
The old dispute between the "correspondence theory" and the "coherence theory" of truth (they should not be called "theories" of course) is simply settled in this way that the "formal" truth, which is the truth of tautological
