Page:Philosophical Review Volume 2.djvu/150

136 called synthetic. And synthetic judgments alone enter into the critical problem. For analytic judgments can be explained at once as the products of the analysis of concepts subject only to the logical law of contradiction, and with that explanation they may be dismissed.

But manifestly not all synthetic judgments come within the purview of a critique of pure reason. This deals only, as we just saw, with a priori judgments. It has nothing therefore to do with the vastly larger number of synthetic judgments, namely, with synthetic judgments a posteriori. And in fact these are all as easily explained as the analytic judgments. For in every a posteriori synthetic judgment, it is experience that enables me to add to the subject a predicate which contains something more than the notion of the subject implied. 'Heavy' is not implied in 'body' as 'extended' is. The experience of the conjunction of that quality with this substance supplies, however, a ground for the synthesis of them in the judgment, Body is heavy.

Both analytic and a posteriori synthetic judgments may therefore be set aside. They present no difficulty as to their possibility. And in any case they are irrelevant to the present inquiry into the possessions of pure reason. We are left, then, with the remainder of human knowledge, a priori synthetic judgments. And to explain under what conditions, and in what fields, a priori synthetic judgments are possible, is to answer the critical question, as originally framed, What and how can reason know without all experience? The object of the Critique, from this point of view, is to inquire into the ground of the possibility of a priori synthetic judgments, as well as to determine the limits of their validity.

But have we such pure knowledge, such a priori synthetic judgments? This is a question of fact that must be settled before we go one step further. For there can be no doubt that all our knowledge at least begins with sense-impressions. It does not, however, therefore follow that it arises from sense-impressions. Even in our common experience, it is possible that mind-given components are mixed with the impressions