Now since we cannot construct a priori the least concept of the pos sibility of dynamical connection, and the category of the pure understanding does not serve for thinking up such a thing but only for understanding it where it is encountered in experience, we cannot orig inally cook up,d in accordance with these categories, a single object with any new and not empirically given property and ground a permissible hypothesis on it; for this would be to found reason on empty figments of the brain rather than concepts of things.