Page:A Brief History of Modern Philosophy.djvu/151

 the conclusion of a syllogism is conditioned by the premises. In any purely subjective representations or in dreams, images may be combined in every variety of ways; we have experience however only when it is impossible to permit the members of a series of perceptions to exchange their places or to pass from one perception to another by means of a leap. In my mind I can at will, e.g. conceive of a house being built from the roof downward or from the foundation upward; but in the case of the actual construction of a house there is but a single possible order of succession. Wherever there appear to be gaps in the series of perceptions we assume that further investigation will discover the intervening members. This demonstration of the validity of the categories of magnitude and causality likewise involves a limitation: The validity of the categories can only be affirmed within the range of possible experience; they cannot be applied to things which from their very nature cannot become objects of experience. Experience is the empirical synthesis which furnishes validity to every other synthesis.

The principles of demonstration by which we obtain our results when dealing with the forms of intuition and the categories are inapplicable to the realm of ideas. The ideas demand an unconditionally, a totality, finality; but experience, which is always limited, never furnishes any such thing. Neither God, nor the soul (as substance), nor the universe (as an absolute whole) can be given in experience. There is here no possibility of an objective deduction. It is impossible to construct a science of ideas.

When Kant bases the real significance of the rational sciences upon an analysis of the conditions of experience, it must of course be remembered that he uses the concept of experience in its strict sense. Experience consists of