The impossibility for the understanding to think two supreme beings, two infinite substances, two Gods, is the impossibility for the understanding to contradict itself, to deny its own nature, to think of itself as divided.
The understanding is the infinite being. Infinitude is immediately involved in unity, and finiteness in plurality. Finiteness—in the metaphysical sense—rests on the distinction of the existence from the essence, of the individual from the species; infinitude, on the unity of existence and essence. Hence, that is finite which can be compared with other beings of the same species; that is infinite which has nothing like itself, which consequently does not stand as an individual under a species, but is species and individual in one, essence and existence in one. But such is the understanding; it has its essence in itself, consequently, it has nothing together with or external to itself which can be ranged beside it; it is incapable of being compared, because it is itself the source of all combinations and comparisons; immeasurable, because it is the measure of all measures,—we measure all things by the understanding alone; it can be circumscribed by no higher generalization, it can be ranged under no species, because it is itself the principle of all generalizing, of all classification, because it circumscribes all things and beings. The definitions which the speculative philosophers and theologians give of God, as the being in whom existence and essence are not separable, who himself is all the attributes which he has, so that predicate and subject are with him identical,—all these definitions are thus ideas drawn solely from the nature of the understanding.
Lastly, the understanding or the reason is the necessary being. Reason exists because only the existence of the reason is reason; because, if there were no reason, no consciousness, all would be nothing; existence would be equivalent to non-existence. Consciousness first founds the distinction between existence and non-existence. In consciousness is first revealed the value of existence, the value of nature. Why, in general, does something exist? why does the world exist? on the simple ground that if something did not exist, nothing would exist; if reason did not exist, there would be only unreason; thus the world exists because it is an absurdity that the world should not exist. In the absurdity of its non-existence is found the true reason of its existence, in the groundlessness
