 All empirical employment of our cognitive faculties in the determination of time fully agrees with this. It is not only that we can undertake all time determination only by the change of external relations (motion) in relation to the permanent in space (e.g., motion of the sun with respect to objects on the earth), but we also have nothing at all permanent, which could underlie the concept of a substance, as intuition, except merely matter, and even this permanence is not derived from outer experience, but is rather presupposed a priori as necessary condition of all time determination, and thus also [of] the determination of inner sense with respect to our own existence by means of the existence of outer things.