All belief must in the first place be grounded upon facts, if it is not to be completely groundless; and therefore the only distinction in proofs that there can be is that belief in the consequence derived therefrom can either be grounded on this fact as _knowledge_ for theoretical cognition, or merely as _faith_ for practical. All facts belong either to the _natural concept_ which proves its reality in the objects of sense, given (or which may possibly be given) before all natural concepts; or to the _concept of freedom_, which sufficiently establishes its reality through the causality of Reason in regard of certain effects in the world of sense, possible through it, which it incontrovertibly postulates in the moral law. The natural concept (merely belonging to theoretical cognition) is now either metaphysical and thinkable completely _a priori_, or physical, _i.e._ thinkable _a posteriori_ and as necessary only through determinate experience. The metaphysical natural concept (which presupposes no determinate experience) is therefore ontological. The _ontological_ proof of the being of God from the concept of an original Being is either that which from ontological predicates, by which alone it can be thought as completely determined, infers absolutely necessary being; or that which, from the absolute necessity of the being somewhere of some thing, whatever it be, infers the predicates of the original Being. For there belongs to the concept of an original Being, inasmuch as it is not derived from anything, the unconditioned necessity of its presence, and (in order to represent this) its complete determination by its [mere][155] concept. It was believed that both requirements were found in the concept of the ontological Idea of a _Being the most real of all_; and thus two metaphysical proofs originated.