So thoroughly is Leibniz imbued with the belief in its validity, that the very conception, that of sufficient reason, which should have been the means of saving him from his contradictions, is used in such a way as to plunge him deeper into them. The principle of sufficient reason may indeed be used as purely formal and external,--as equivalent to the notion that everything, no matter what, has _some_ explanation. Thus employed, it simply declares that everything has _a_ reason, without in the least determining the _what_ of that reason,--its content. This is what we mean by calling it formal. But this is not the way in which Leibniz conceives of it. According to him, it is not a principle of the external connection of one finite, or phenomenal, fact with another. It is a principle in the light of which the whole phenomenal world is to be viewed, declaring that its ground and meaning are to be found in reason, in self-conscious intelligence. As we have seen, it is equivalent, in Leibniz's case, to the notion that we have no complete nor necessary knowledge of the world of scientific fact until we have referred it to a conditioning "Supreme Spirit." Looked at in this way, we see that the unity which Leibniz is positively employing is an organic unity, a unity of intelligence involving organic reference to the known world. But such a conception of sufficient reason leaves no place for the final validity of identity and non-contradiction; and therefore Leibniz, when dealing with his method, and not, as in the passages referred to, with his subject-matter, cannot leave the matter thus. To do so indeed would have involved a complete reconstruction of his philosophy, necessitating a derivation of all the categories employed from intelligence itself (that is, from the sufficient or conditioning reason). But the bondage to scholastic method is so great that Leibniz can see no way but to measure intelligence by the ready-made principle of identity, and thus virtually (though not in purpose) to explain away the very principle of sufficient reason. In Leibniz's words: "Contingent truths require an infinite analysis which only God can carry out. Whence by him alone are they known _a priori_ and demonstratively. For although the reason can always be found for some occurring state in a prior state, this reason again requires a reason, and we never arrive in the series to the ultimate reason. But this _progressus ad infinitum_ takes (in us) the place of a sufficient reason, which can be found only outside the series in God, on whom all its members, prior and posterior depend, rather than upon one another. _Whatever truth, therefore, is incapable of analysis, and cannot be demonstrated from its own reasons, but has its ultimate reason and certainty only from the divine mind, is not necessary._ Everything that we call truths of fact come under this head, and this is the root of their contingency."