Freedom in this signification is a pure transcendental idea, which, first, contains nothing borrowed from experience, and second, the object of which also cannot be given determinately in any experience, because it is a universal law even of the possibility of all experience that everything that happens must have a cause, and hence that the causality of the cause, as itself having happened or arisen, must in turn have a cause; through this law, then, the entire field of experience, however far it may reach, is transformed into the sum total of mere nature.