Humes Fork The Natural Division Of Objects Philosophy
Hume's "fork" is the natural division of the objects of human reason or enquiry into two kinds.
The two kinds or "prongs" of the fork are Relations of Ideas and Matters of Fact.
Hume, as an empiricist, used it to deny that knowledge of the world is given by reasoning alone, which is a central Rationalist assumption.
In the Preface to the Prolegomena Kant considers the supposed science of metaphysics.
He states that "no event has occurred that could have been more decisive for the fate of this science than the attack made upon it by David Hume" and goes on to say that "Hume proceeded primarily from a single but important concept of metaphysics, namely, that of the connection of cause and effect" (Baird, p.539).
Over the next few pages Kant defends the importance of Hume's "attack" on metaphysics against common-sense opponents such as Thomas Reid, James Oswald, James Beattie, and Joseph Priestley (all of whom, according to Kant, missed the point of Hume's problem), and Kant then famously writes "I openly confess my recollection of David Hume was the very thing which many years ago first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy a quite new direction.""(Baird, p.541) Thus, it was Hume's "attack" on metaphysics (and, in particular, on the concept of cause and effect) which first provoked Kant himself to undertake a fundamental reconsideration of this science.
Later, in Sections 27-30 of the Prolegomena, Kant returns to Hume's problem and presents his own solution.
Kant begins, in Section 27, by stating that "now we are prepared to remove Hume's doubt" (Baird, p.568); and he continues, in Section 29, by proposing "to test Hume's problematic concept (his crux metaphysicorum), the concept of cause" (Baird, p.568).
Kant concludes, in Section 30, by stating that we are now in possession of a complete solution of the Humean problem which, Kant adds, "rescues for the pure concepts of the understanding of their a priori origin and for the universal laws of nature their validity as laws of the understanding"(Baird, p.569).
Thus, Kant's "complete solution of the Humean problem" directly involves him with his whole revolutionary theory of the constitution of experience by the a priori concepts and principles of the understanding-and with his revolutionary conception of synthetic a priori judgements.
Indeed, when Kant first introduces Hume's problem in the Preface to the Prolegomena he already indicates that the problem is actually much more general, extending to all of the categories of the understanding (4, 260; 10): "I therefore first tried whether Hume's objection could not be put into a general form, and soon found that the concept of the connection of cause and effect was by no means the only concept by which the understaning thinks the connection of things a priori, but rather that metaphysics consists altogether of such concepts.
I sought to ascertain their number; and when I had asatisfactorily succeeded in this by starting from a single principle, I proceeded to the deduction of these concepts, which I was now certain were not derived from experience, as Hume had attempted to derive them, but sprang from the pure understanding."(Baird, p.541) Moreover, Kant soon explains, in Section 5, how this more general problem (common to all the categories and principles of the understanding) is to be formulated: how is cognition from pure reason possible or, more specifically, how are synthetic a priori propositions possible?
Kant insists that the possibility of metaphysics as a science entirely depends on this problem that metaphysics, until now, has remained in such a wavering state of uncertainty and contradictions is to be ascribed solely to the fact that this problem, and perhaps even the distinction between analytic and synthetic judgements, was not thought of earlier.
Metaphysics stands or falls with the solution of this problem, or on a satisfactory proof that the possibility it requires to be explained does not in fact obtain.
He suggests, once again, that Hume failed to perceive the solution because he stopped with the synthetic proposition of the connection of the effect with the cause.
Given the crucial importance of the Prolegomena in this respect, it is natural to return to Kant's famous remarks in the Preface to that work, where, as we have seen, Kant says that it was the "recollection of David Hume was the very thing which many years ago first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy a quite new direction." It is natural to wonder, in particular, about the precise years to which Kant is referring and the specific events in his intellectual development he has in mind.
Here, however, we now enter controversial terrain, where there are basically two competing alternatives-both of which reflect the circumstance that Kant could read Hume only in German translation.
THREE: In Hume's critique of the concept of cause and effect, he did question the principle of causality, and the way in which he expressed the defect of such a principle made sense to Kant.
Hume had decided that the lack of certainty for cause and effect was because of the nature of the relationship of the two events.
Just like Hume, Kant does not feel that rationality should be the basis for morality.
While it is common to say that Hume denied the existence of synthetic a priori propositions, there is some question about whether he actually does.
He says that the relationship of cause and effect is not discovered or known by any reasoning a priori, but that is not the same thing.
A synthetic a priori proposition is not known from any reasoning.
In fact, Hume does not see that the relationship of cause and effect is discovered or known from anything, since it is not justified by experience, in which there is no necessary connection between cause and effect, and there is in fact nothing in the cause to even suggest the effect, much less than the effect must follow.
Hume felt that we become accustomed to the association of certain events (causes) with others (effects); but this carries no weight about the nature of things, which is what makes Hume a skept.
In the Critique of Pure Reason, Kant, however, believes that concepts like causality are conditions of the possibility of experience, because they are the rules by which perception and experience are united into a single consciousness called synthesis.
Once the existence of consciousness is accepted then whatever is necessary for the existence of consciousness must be accepted.
His is a strong argument and is of great value, especially when we untangle it from the earlier views of perception in the Critique.
However, it suffers from a couple of drawbacks.
One is that, like Hume's own explanation, it is an approach that does not necessarily tell us anything about objects.
Kant seemed to recognize this himself when he said that none of this gives us any knowledge of things in themselves.
Kant never properly sorted out this problem.
The second drawback of Kant's argument is that it would only work for the possibility of experience, and not for any other matters, which seem to me, to involve synthetic a priori propositions.