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 must have a first member if the universe is to be regarded as a complete system, and if a complete causal explanation of particular phenomena shall be possible. But the assumption of a first cause is in conflict with the law of causality, for this cause would itself have no cause, and at what moment should it begin its operation?

According to Kant the only way to avoid these antinomies is to distinguish between phenomenon and the thing-in-itself and limit the validity of our knowledge to phenomena. We meet with contradictions the moment we attempt to apply our concepts to the things which transcend our circumscribed experience. Kant therefore regards the antinomies as a demonstration of his theory of knowledge.

c. Criticism of speculative theology. Reflective thought aims to find in the concept of God an absolute resting- place for all its effort. This concept is supposed to contain the ground of the concepts of soul and universe. In it knowledge would attain its ideal: all ideas would be referred to a single idea which in turn contains the ground of its existence within itself and hence implies nothing beyond it! According to Kant the concept of God is fully justified as an ideal; but we must not confuse an ideal of knowledge with knowledge actually attained. The traditional arguments for the existence of God however rest upon such a confusion of terms.

The most popular argument rests upon the adaptation of nature and thence infers the existence of an all-wise, all-loving and all-powerful Creator (the physico-theological argument).—But by what right do we presuppose that the order and adaptation of nature should not be explainable as the effects of natural causes operating according to natural laws? And at any rate this argument can only lead to