But to assume the soul as simple substance (a transcendent concept) would be a proposition that would not only be indemonstrable (as is the case A with many physical hypotheses), but which would also be hazarded en tirely arbitrarily and blindly, since the simple cannot come forth in any experience at all, and, if one here understands by substance the per sistent object of sensible intuition, there can be no insight at all into the possibility of a simple appearance.