Context

Sections 1 through 5 examine our ideas of space and time, which is the topic announced in the title of Part 2. The present section is the last in this part of Book I, and it shifts the discussion to a different pair of ideas, those of existence and of external existence.

Background

Locke had discussed the difference between “real” and “fantastical” ideas in Book IV, Chapter XXX of the Essay concerning Human Understanding. Ideas are supposed to represent and be caused by other beings, their “archetypes.” This supposition may or may not be correct, so we distinguish between real and fantastical ideas. “First, by real ideas, I mean such as have a foundation in nature; such as have a conformity with the real being and existence of things, or with their archetypes. Fantastical or chimerical, I call such as have no foundation in nature, nor have any conformity with that reality of being to which they are tacitly referred, as to their archetypes.” The fact that we make this distinction presupposes that we have an idea of existence distinct from the ideas that are supposed to represent the existence of things, an idea, that is, of external existence.

Berkeley famously claimed, on the contrary, that there is no difference between the existence of an unperceiving thing and its being perceived. First, he held that “the existence of an idea consists in being perceived” (Principles of Human Knowledge, Section 2). Second, he claimed that the only thing that an idea can represent is something that itself can be perceived, so that the existence of what is perceived by an idea is the existence of an idea. His argument is found in the Principles, Section 22.

But, say you, surely there is nothing easier than to imagine trees, for instance in a park, or books existing in a closet, and nobody by to perceive them. I answer you may so, there is no difficulty in it; but what is all of this, I beseech you, more than framing in your mind certain ideas which you call books and trees, and at the same time omitting to frame the idea of anyone that may perceive them? But do not you yourself perceive or think of them all the while? This therefore is nothing to the purpose; it only shows you have the power of imagining or forming ideas in your mind; but it does not show that you can conceive it possible the objects of your thought may exist without the mind. To make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest repugnancy. When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas.

The Treatise

1. This last section of Part 2 is supposed to “explain the ideas of existence and external existence.” The discussion of the main topic of Part 2, the ideas of space and time, has been concluded, and the only thing the author says to connect the previous discussion with the present one is that both kinds of ideas “have their difficulties.” Whatever the connection with ideas of space and time, the treatment of the ideas of existence and external existence will aid in the examination of knowledge and probability in Part 3, since it will complete the explanation of “all those particular ideas, which may enter into our reasoning.” [In Section 1 of Part 3, paragraph 2, the author states that “No one can once doubt but existence and non-existence destroy each other, and are perfectly incompatible and contrary.” As a result, the relation of contrariety can be discovered from the mere comparison ideas and therefore may be known. Beginning in Section 2, the author describes causal reasoning as resulting in belief in the existence or non-existence of an object. In Section 2 he states: “ Here then it appears, that of those three relations, which depend not upon the mere ideas, the only one, that can be trac’d beyond our senses, and informs us of existences and objects, which we do not see and feel, is causation” (paragraph 3). The result of causal reasoning is belief in the existence of the object, and belief itself is a lively idea of the object (Section 7). Thus, belief in the existence of an object involves nothing beyond a perception and does not involve a separate idea of existence or external existence.]

2. The author asserts, without argument, that every idea or impression of any kind, of which we are presently conscious, or which we remember, is “conceiv’d as existent.” According to the author, it is “evident” that the consciousness of our perceptions provides us with “the most perfect idea and assurance of being.” [Compare Berkeley’s claim, noted above, that “the existence of an idea consists in being perceived.”] This leads to “a dilemma, the most clear and conclusive that can be imagin’d.” Given that “we never remember any idea or impression without attributing existence to it,” there are two possibilities:

• The idea of existence must be derived from an impression that is distinct from, though conjoined with, every perception (object of thought), or
• The idea of existence is the same as the idea of the perception (object of thought).

The dilemma is a consequence of the copy principle: that every [simple] idea is a copy of a [simple] impression, which it resembles. [Otherwise, it might be possible for a person to generate an idea of existence separate from that of a perception, without there being a corresponding impression from which the idea of existence arises.] Further, the resolution of the dilemma also follows from the copy principle. The first alternative cannot be correct, so the second must be. The only way for an impression to be conjoined with every impression and idea is for the two to be inseparable. The author has claimed earlier (Part 1, Section 3) that what is distinct is separable, from which it follows that what is inseparable is not distinct. So the idea of existence works differently from other ideas we have, in that at least some ideas can be separated. “Tho’ certain sensations may at one time be united, we quickly find they admit of a separation, and may be presented apart.” The author concludes that the first alternative has been eliminated: “tho’ every impression and idea we remember be consider’d as existent, the idea of existence is not der’ved from any particular impression.”

4. The conclusion is that “idea of every existence . . . is the very same with the idea of what we conceive to be existent.” There is no difference in thinking about a thing simply and thinking about a thing as existing. “That idea [of existence], when conjoin’d with the idea of any object, makes no addition to it.” [This claim is echoed in Kant’s objection to the ontological proof of the existence of God.] If something is conceived of, it is conceived of as existing. “Any idea we please to form is the idea of a being; and the idea of a being is any idea we please to form.”

5. Anyone who denies this thesis must accept what is “impossible.” That is, the proponent of a separate idea of existence must show which impression is its original and “must prove, that this impression is inseparable from every perception we believe to be existent.” This is impossible because distinctness is incompatible with inseparability.

6. One might think that the dilemma may be evaded by appeal to what the author has described as the ability to make distinctions without separating ideas. (Part 1, Section 7). But this admitted “distinction of ideas without any real difference” is of no help. There can be a “distinction of ideas” when an idea resembles different ideas in different “aspects.” Thus, a white globe resembles a white cube in one way and does not resemble a black globe in another way, so that the color of the globe can be distinguished from the shape of the globe. “But no object can be presented resembling some object with respect to its existence, and different from others in the same particulars.” Because the idea of existence accompanies every idea, one cannot say that the idea of a white globe resembles some existing thing in that it exists but does not resemble in the aspect of existence, something that does not exist, since there is no perception that is not accompanied by the idea of existence.

7. The train of reasoning we have followed concerning the idea of existence can be adapted to apply to the idea of external existence. The author begins with the observation that all philosophers agree, and it is “pretty obvious of itself,” that only perceptions (impressions and ideas) are present to the mind, and that “external objects become known to us only by those perceptions they occasion.” Loving, hating, thinking, feeling, seeing are all nothing but perceiving.

8. Given that all that is before the mind is perceptions, and that all ideas are derived from perceptions that were previously before the mind, it is impossible for anyone to conceive (form an idea) of something “specifically different” from a perception. [By “specifically different” from perceptions, the author seems to mean “different in species,” or “of a different kind” from perceptions.] We may use our imagination to conceive of objects “out of ourselves as much as possible,” such as what is in deep space, or even at the edge of the universe. Despite our efforts, “we never really advance a step beyond ourselves.” Whatever it is that we conceive (say, a distant galaxy), when we think of it as existing, we are only thinking in a certain way of our perceptions, which are confined to our imagination. “This is the universe of the imagination, nor have we any idea but what is there produc’d.” [Compare this with Berkeley’s argument from the Principles, Section 22, quoted above.]

9. In the concluding paragraph, the author hints at how one might approach “a conception of external objects,” in a sense in which they are different in kind from perceptions. The idea of an external object would be a “relative idea,” which would not give any information about the objects that are “external” to our perception. [The author seems to have in mind here something like this, that external objects are the non-perceptions which are causes of our impressions of sensation.] On the other hand, “generally speaking” people do not suppose external objects to be different in kind from perceptions. Instead, they only distinguish between perceptions in “different relations, connexions, and durations.” The author does not elaborate on this suggestion here, but promises to discuss it later, in Part 4, Section 2. [The claim is first made in paragraph 12.]

The Enquiry

The topic of this section is not discussed in the Enquiry.

[ Previous Section | Next Section | Treatise Contents | Text of the Treatise ]