III. By the objective reality of an idea I understand the entity or being of the thing represented by the idea, in so far as this entity is in the idea; and, in the same manner, it may be called either an objective perfection or objective artifice, etc. (artificium objectivum). For all that we conceive to be in the objects of the ideas is objectively [or by representation] in the ideas themselves.
IV. The same things are said to be formally in the objects of the ideas when they are in them such as we conceive them; and they are said to be in the objects eminently when they are not indeed such as we conceive them, but are so great that they can supply this defect by their excellence.
V. Everything in which there immediately resides, as in a subject, or by which there exists any object we perceive, that is, any property, or quality, or attribute of which we have in us a real idea, is called substance. For we have no other idea of substance, accurately taken, except that it is a thing in which exists formally or eminently this property or quality which we perceive, or which is objectively in some one of our ideas, since we are taught by the natural light that nothing can have no real attribute.
VI. The substance in which thought immediately resides is here called mind (mens, esprit). I here speak, however, of mens rather than of anima, for the latter is equivocal, being frequently applied to denote a corporeal object.
VII. The substance which is the immediate subject of local extension, and of the accidents that presuppose this extension, as figure, situation, local motion, etc., is called body. But whether the substance which is called mind be the same with that which is called body, or whether they are two diverse substances, is a question to be hereafter considered.
VIII. The substance which we understand to be supremely perfect, and in which we conceive nothing that involves any defect, or limitation of perfection, is called God.
IX. When we say that some attribute is contained in the nature or concept of a thing, this is the same as if we said that the attribute is true of the thing, or that it may be affirmed of the thing itself.
X. Two substances are said to be really distinct, when each of them may exist without the other.
Postulates
1st. I request that my readers consider how feeble are the reasons that have hitherto led them to repose faith in their senses, and how uncertain are all the judgments which they afterwards founded on them; and that they will revolve this consideration in their mind so long and so frequently, that, in fine, they may acquire the habit of no longer trusting so confidently in their senses; for I hold that this is necessary to render one capable of apprehending metaphysical truths.
2nd. That they consider their own mind, and all those of its attributes of which they shall find they cannot doubt, though they may have supposed that all they ever received by the senses was entirely false, and that they do not leave off considering it until they have acquired the habit of conceiving it distinctly, and of believing that it is more easy to know than any corporeal object.
3rd. That they diligently examine such propositions as are self-evident, which they will find within themselves, as the following:—That the same thing cannot at once be and not be; that nothing cannot be the efficient cause of anything, and the like;—and thus exercise that clearness of understanding that has been given them by nature, but which the perceptions of the senses are wont greatly to disturb and obscure—exercise it, I say, pure and delivered from the objects of sense; for in this way the truth of the following axioms will appear very evident to them.
4th. That they examine the ideas of those natures which contain in them an assemblage of several attributes, such as the nature of the triangle, that of the square, or of some other figure; as also the nature of mind, the nature of body, and above all that of God, or of a being supremely perfect. And I request them to observe that it may with truth be affirmed that all these things are in objects, which we clearly conceive to be contained in them: for example, because that, in the nature of the rectilineal triangle, this property is found contained—viz., that its three angles are equal to two right angles, and that in the nature of body or of an extended thing, divisibility is comprised (for we do not conceive any extended thing so small that we cannot divide it, at least in thought)—it is true that the three angles of a rectilineal triangle are equal to two right angles, and that all body is divisible.
5th. That they dwell much and long on the contemplation of the supremely perfect Being, and, among other things, consider that in the ideas of all other natures, possible existence is indeed contained, but that in the idea of God is contained not only possible but absolutely necessary existence. For, from this alone, and without any reasoning, they will discover that God exists: and it will be no less evident in itself than that two is an equal and three an unequal number, with other truths of this sort. For there are certain truths that are thus manifest to some without proof, which are not comprehended by others without a process of reasoning.
6th. That carefully considering all the examples of clear and distinct perception, and
