But still, a priori, he could not know even this much. Thus, if a man undermined his house, we say, вЂњhe might know a priori that it would have fallen вЂќ that is, he needed not to have waited for the experience that it did actually fall.

For, in speaking of knowledge which has its sources in experience, we are wont to say, that this or that may be known a priori, because we do not derive this knowledge immediately from experience, but from a general rule, which, however, we have itself borrowed from experience. It is, therefore, a question which requires close investigation, and not to be answered at first sight, whether there exists a knowledge altogether independent of experience, and even of all sensuous impressions? Knowledge of this kind is called a priori, in contradistinction to empirical knowledge, which has its sources a posteriori, that is, in experience.Д«ut the expression, вЂњa priori,вЂќ is not as yet definite enough adequately to indicate the whole meaning of the question above started. For, on the contrary, it is quite possible that our empirical knowledge is a compound of that which we receive through impressions, and that which the faculty of cognition supplies from itself (sensuous impressions giving merely the occasion), an addition which we cannot distinguish from the original element given by sense, till long practice has made us attentive to, and skilful in separating it. For how is it possible that the faculty of cognition should be awakened into exercise otherwise than by means of objects which affect our senses, and partly of themselves produce representations, partly rouse our powers of understanding into activity, to compare to connect, or to separate these, and so to convert the raw material of our sensuous impressions into a knowledge of objects, which is called experience? In respect of time, therefore, no knowledge of ours is antecedent to experience, but begins with it.Д«ut, though all our knowledge begins with experience, it by no means follows that all arises out of experience. That all our knowledge begins with experience there can be no doubt. Of the difference between Pure and Empirical Knowledge The Critique of Pure Reason by Immanuel Kant, translated by J.

Immanuel Kant The Critique of Pure Reason

Critique of pure reason