Critique of the theory of Heraclitus:

All is change. True. But if there is but change, this change must take place in something. This something is what we call substance, Being.

Any 2 opposite opinions are absolutely identical.

All that begins has a cause (Vallet).

It was very soon clear to me that antinomies must have some exploration. I found the contrast of 2 opinions a

false: contrast. To contrast two things, it is needful that they should be of the same nature. I can contrast an apple and a pear, but not an apple and a cat. And the fact of these theories being antithetic I found to be the fact that they are of a different nature, one being a priori, the other being deduced from experience.