We cannot conceive, without conceiving _some thing, a being_; and this is substantive being. We cannot affirm or deny without saying, _is_, or _is not_; and this is copulative being. The idea of being is, therefore, less an idea than a condition necessary to enable our understanding to exercise its functions; it is not a type representing nothing determinate; it is rather the very condition of its life, without which it cannot possibly exercise its activity. 87. But we can, by reflection, perceive this condition of all our thoughts; the idea of being, standing, as it does, involved with the others, is then presented purified to our eyes, and we conceive that general reason of _being_, or _thing_, which enters into all our perceptions, but which we had not previously distinguished with sufficient clearness. CHAPTER XII. DISTINCTION BETWEEN ESSENCE AND EXISTENCE. 88. It has been much disputed in the schools whether existence is distinct from essence. At first sight, this seems an indifferent question; but such it is not, if we attend to the consequences which, in the opinion of respectable authors, flow from it; for they pretend to no less than establishing upon the distinction between essence and existence a characteristic note of the finite, attributing to infinite being alone, the identity of its essence with its existence. 89. That we distinguish between the essence and the existence of things is beyond all doubt; for inasmuch as we know an object realized, we conceive its existence; and inasmuch as we know that this object exists with this or that determination, constituting it in such or such a species, we conceive its essence. The idea of existence represents to us pure reality; the idea of essence offers us the determination of this reality. The schools, however, not satisfied with this, have endeavored to transfer to things that distinction which we discover in our conceptions; but their opinion seems to be subtle rather than solid. 90. The essence of a thing is that which makes it what it is, and distinguishes it from all else; and existence is the act which gives being to essence, or that by which essence exists. It would appear, from these definitions, that there really is no distinction between essence and existence. To render two things distinct, it is requisite that one be not the other; but since essence, abstracted from existence, is nothing, we cannot say that there is a real distinction between them. To what is the essence of a man, if we abstract his existence, reduced? To nothing; and therefore, no relation between them is admissible. We grant that when we abstract the existence of man, we do yet conceive the essence of man; but the question is not whether we distinguish between the idea of man and his existence, but whether there is a real distinction between his own essence and existence.