Locke's Dilemma:
Does Locke's position constitute a 'veil of perception'?

Chris Mitchell
Class: Empiricists and Kant

╬Twixt that, and reason, what a nice barrier,
Forever separate, yet forever near!
Remembrance and reflection how allied:
What thin partitions sense from thought divide:
And middle natures, how they long to join,
Yet never pass the insuperable line!

- from Alexander Pope's "An Essay on Man."

In this paper I shall argue that Locke may be defended in two significant ways from the charges of total skepticism that the ╬veil of perception' entails. First, I shall argue that Locke's theory is not a representative theory but a causal theory. Secondly, I argue that Locke's position entails a dilemma that effectively defends him against charges of total skepticism, by adjusting the criteria for knowledge away from certainty and towards probability.

According to the majority of accounts, Locke's theory of perception is a representative theory. Jonathan Bennett's ╬veil of perception' is an alternative name for the representative theory. Bennett adopts the former phrase because the latter "does not express what is wrong with the theory" [Bennett 69]. The term ╬veil of perception' refers to the fact that everything we are aware of is mediated by our senses. As we are only aware of things through our senses, it is as though we perceive through a ╬veil of perception'. In order to decide whether Locke's ideas constitute a ╬veil of perception' we must decide whether Locke's theory can be correctly construed as a representative theory. The representative theory of perception: we are only aware of the existence of external objects through the mediation of the ideas we have of them; we cannot say that we know that these ideas actually represent those objects; we cannot say we know that there are any external objects whatsoever. The representative theory of perception, the critics assert, leads to total skepticism.

It now remains to discover whether or not Locke's position entails the kind of gross skepticism that a purely representative theory of perception necessitates; there is evidence it does. For examples, I shall paraphrase two arguments that are interpreted as asserting, or entailing the representative theory of perception. First, in Book IV, Chp. II, Sec. 14, Locke presents an argument for " the particular existence of finite beings without us" [Locke p. 537].

Argument from Vividness
  1. There is a difference between ideas that we recall in memory and the ideas that are from direct experience.
  2. The difference between these ideas is that the ideas from experience are much more vivid, or apparent than the ideas from memory.
  3. Ideas that are caused by external objects are more vivid, or apparent than ideas from memory.
  4. Therefore, the ideas from experience correspond to external objects.

This argument, to which I have added the suppressed premise three, may be easily criticized by anyone who takes the skeptical tack. Premise three asserts that ideas that are caused by external objects are more vivid; however, this premise begs the question, since it is the existence of external objects that is under contention. Locke cannot assert he knows that external objects exist because external objects produce his most vivid sensations. Hence, the critic asserts, Locke is left with a skeptical view. Another attempt Locke makes to show the existence of external objects occurs in Book IV, Chp. IV, Sec. 3-5. I have paraphrased it as follows.

Argument from Conformity
  1. The mind does not know things immediately.
  2. The mind only knows things through the intervention of its ideas of those things.
  3. Our knowledge shall be considered real only if our ideas conform to the reality of things.
  4. There are no innate simple ideas.
  5. Our simple ideas must be physically caused by something external to mind.
  6. Simple ideas represent to us the primary qualities of the things that cause them.
  7. Since the idea of x in the mind exactly answers the power y which is in any body to produce the idea of x in the mind, the idea has all the real conformity it can, or ought to have with 'things out there'.
  8. Therefore, the conformity between our Simple ideas and the existence of things is sufficient for real knowledge.

In this case the critic would target premise six and assert, once again, that the premise begs the question. In order to assert that the idea in x exactly answers the power in body y, Locke requires some independent evidence beyond the evidence of his senses, because it is this latter evidence that is in question. Since we can not reach beyond the evidence of our senses in order to be certain whether or not they resemble or represent the world-as-it-is, we should not assert that we know they do, claims the critic. Once again, it appears, Locke's position entails skepticism. These arguments form the basis of the critiques of this interpretation of Locke's theory of perception.

Jonathan Bennett uses this kind of argument in his book, Locke, Berkeley, Hume, against Locke's position. Bennett states the problem as follows:

Locke represents the difference between (a) seeing a tree and (b) being in a visual state as of seeing a tree though there is no tree there to be seen, as the difference between (a) having a visual ╬idea' while in the presence of a corresponding ╬real thing' and (b) having such an ╬idea' while not confronted by any such ╬real things'. [Bennett p.69]

Bennett argues that unless we have some independent source of information about this outside realm, we are quite incapable of certainty regarding its nature, or even its existence. Is Locke's position untenable? One possibility that may yet save Locke is that perhaps he does not hold a representative theory of perception at all. If this is the case, then perhaps all the criticisms are aimed at a ╬straw man'. An alternate position that Bennett offers is that Locke may have a causal theory of perception. Although Bennett does not feel that this option releases Locke from his inevitable skeptical conclusions, in the interests of fairness I shall examine this possibility first, and reintroduce Bennett's criticisms immediately following.

First, we should determine what constitutes a causal theory of perception. In his book, Perceptual Knowledge: an Analytical and Historical Study, Georges Dicker states the classic causal theory of perception as:

1) that the sense-data obtained by perceiving a physical thing M are partly caused by M, and (2) that a person could justify the claim to perceive M by an argument showing that M was causally required to account for certain of his sense-data. [Dicker p. 91]

Once we examine the evidence in Locke's An Essay Concerning Human Understanding, it becomes apparent that it does present a causal theory of perception. That ideas are caused by something exterior to mind is entailed by the fact that Locke feels there are no innate ideas. How then does Locke argue we come to have ideas? Locke's causal theory of perception is based on the principles of corpuscularianism: the belief that all things are made up of tiny particles called corpuscles. The activity of these corpuscles results in our ideas of the qualities of physical objects through direct causal interaction with the sensory organs themselves. In Book II, Chp. VIII, Sec. 4, Locke asserts that sensation is exclusively the result of "different degrees and modes of Motion in our animal Spirits, variously agitated by external Objects" [Locke p.133]. Evidence for his corpuscularianism is also found in Sec. 12:

And since the Extension, Figure, Number and Motion of Bodies of an observable bigness, may be perceived at a distance by the sight, ╬tis evident some singly imperceptible Bodies must come from them to the Eyes, and thereby convey to the Brain some Motion, which produces these Ideas, which we have of them in us. [Locke p.136]

I cannot ... conceive how Bodies without us, can any ways affect our Senses, but by the immediate contact of the sensible Bodies themselves, as in Tasting and Feeling, or the impulse of some insensible Particles coming from them, as in Seeing, Hearing, and Smelling; by the different impulse of which Parts, caused by their different size, Figure, and Motion, the variety of Sensations is produced in us. [Locke p.536]

In light of these passages and others in the text, it seems that Locke held a causal theory of perception. In accordance with the classic definition of causal theory, Locke justifies his claim to perceive M by arguing: ideas do not stem from the mind, therefore, physical objects must be causally required to account for ideas of physical objects. Specifically, these objects are required for our ideas of primary qualities. Locke states that he ╬cannot conceive' how it could be possible to have these ideas except through this causal relationship.

Jonathan Bennett claims that this theoretical shift does not really help Locke's situation at all. The objections to the causal theory of perception have exactly the same consequences as the objections to the representative theory of perception. Bennett's objection is that in order to know whether or not the causal chain exists, in the manner Locke believes it exists, Locke would require exactly the same kind of independent evidence that was required to know whether or not the world was correctly represented. Consequently, we have no more evidence for the existence of external objects that we did before we adopted the causal theory.

In opposition to Bennett, I argue that Locke presents a significant defense against the charges of skepticism. In the last section of Book I, after having denied the possibility of innate ideas or principles, Locke makes a statement that has far-reaching implications for a sympathetic reading of his text. I assert that this passage effectively sets up a dilemma that defends Locke against the charges of total skepticism.

Wherein I warn the Reader not to expect undeniable cogent demonstrations, unless I may be allow'd the privilege, not seldom assumed by others, to take my Principles for granted; and then, I doubt not, but I can demonstrate too [Locke p.103]. The argument takes this form: Locke's Dilemma
  1. Either you accept Locke's general principles or you do not accept Locke's general principles.
  2. If you accept Locke's general principles, then he is able to demonstrate his position.
  3. If you do not accept Locke's general principles, then you should not expect certainty.
  4. Therefore, either Locke is able to demonstrate his position or you should not expect certainty.

This argument is not to be understood in the fairly simplistic sense of, ╬either Locke can prove his position or he cannot'; rather, the argument points to two different knowledge criteria in Locke's argument. On one horn of the dilemma, Locke feels that given certain principles, it is possible for him to reach deductively certain conclusions about the world-as-it-is. On the other horn, Locke recognizes that without these underlying principles, the drift into skepticism is inevitable. In response to the skeptic, however, Locke uses both inductive and pragmatic arguments to assert that we do have knowledge; though, it may not be certain.

According to the first horn of his dilemma, if we grant him his principles, Locke asserts that he is able to ╬demonstrate' his position. Demonstrative knowledge requires "a steddy application by steps and degrees, before the Mind can in this way arrive at Certainty" [Locke p532]. Demonstrative knowledge is a system of proofs in which each step is affirmed intuitively but whose final truth can not be revealed except by means of the intervening steps [Locke p. 533-4] Now that we know Locke's method, we must determine which principles he requires in order to demonstrate his position. These principles may be enumerated as follows:

i) There are no ideas which are innate to mind.
ii) If no ideas are innate to mind, then ideas must stem from something external to mind.
The next two principles that I shall cite are those which are so wholly open to skepticism that they are often rejected prima facie: iii) The ideas of primary qualities of objects represent the actual qualities of the physical objects themselves.
iv) There is a direct causal connection between the things themselves and the ideas I have of those things.

If we are to give Locke a fair reading, we should examine his argument in light of these principles.

According to Locke's general principles, is he committed to the view that the fact that he is only immediately aware of ideas prevents him from ever having certain knowledge of the world-as-it-is? No. According to Locke's principles, he knows, from (i) and (ii) that ideas proceed from something external to mind since ideas cannot proceed from mind. He knows that he has ideas of extension, figure, motion, mobility and solidity. He knows , from (iv), that the ideas he receives from the world-as-it-is are the direct result of a physical causal chain that began with the objects themselves and culminated in his ideas of those things. Finally, Locke knows, from (iii), that the ideas he has of the primary qualities of objects really represent the qualities of the objects themselves. As for whether or not we can view secondary qualities without skepticism, Locke states explicitly that we cannot. However, it is clear that Locke cannot be accused of total skepticism on this horn of the dilemma.

How then does Locke fare on the other horn of the dilemma? It would seem that his position becomes instantly untenable. All his general principles are once again open to the skeptic's critiques. Principles iii) and iv) beg the question, once again, and Locke's argument quickly unravels as a consequence. However, the premise behind the second horn of the dilemma says that the reader "should not expect undeniable cogent demonstrations" [Locke p. 103]. This premise changes the knowledge criteria for Locke's argument and acts as a final defense against the charges of skepticism.

First, the charges: Principle iii) begs the question: Locke cannot reach beyond the knowledge of his senses to assert that that which lies external to his senses corresponds to his senses. Principle iv) also begs the question: Locke needs independent evidence to assert that he knows the nature of the causal connection. However, I argue that, with Locke's adjusted knowledge criteria, certainty is not a necessary condition for knowledge. According to this horn, Locke's previous arguments, such as the Argument from Vividness and the Argument from Conformity, become strong inductive arguments. In addition, Locke adopts pragmatic arguments against unbridled skepticism. For instance, note the pragmatic quality of the following inductive argument concerning the relationship between his ideas-of-things and the things-in-themselves:

our ideas do as well serve us to that purpose, and are as real distinguishing Characters, whether they be only constant Effects, or else Resemblances of something in the things themselves; the reality lying in that steady correspondence, they have with the distinct Constitutions of real Beings. But whether they answer to those Constitutions, as to Causes, or Patterns, it matters not; it suffices, that they are constantly produced by them [Locke p.373].

This argument states: even if we don't know that the world-as-it-is corresponds to our sense-data, we have enough evidence that the world-as-it-is constantly produces the same sense-data, under the same circumstances, that we may act as though there is uniformity. Much of Locke's causal theory of perception depends on ╬insensible particles' whose effects bear no resemblance to the things that cause them. In answer to problems such as these, Locke states:

That the certainty of things existing in rerum Natura, when we have the testimony of our Senses for it, is not only as great as our frame can attain to, but as our Condition needs [Locke p.634]

This is, once again, a highly pragmatic argument against the kind of skeptical concerns, that Jonathan Bennett raises. Locke's arguments accuse skeptics of taking skepticism too far. It is one thing to doubt; but, if we must doubt all the evidence of our senses, if uncertainty is the overriding principle of our theory, then it seems we have taken the exercise too far. The skeptic's dependence on certainty can become an obstacle in his acquisition of knowledge. Locke is asserting that the combined strength of his inductive arguments with the addition of an effective pragmatic argument against skepticism is enough for any reasonable person to attest that they have knowledge of external objects. The skeptic may object that this formulation merely sidesteps the issue (on the one horn Locke defines his way into certainty and, on the other horn he asserts that certainty isn't necessary for knowledge) nevertheless, this objection would miss the pragmatic element of Locke's theory. Do Locke's ideas constitute a ╬veil of perception' between our minds and reality? The answer to this question depends on the criteria you adopt:

1) Can we be deductively certain that our ideas represent the world-as-it-is? No, we cannot have certainty without access to independent facts about the world.
2) Do we have enough evidence to convince us that the world which lies beyond our senses corresponds to our sensory evidence, enough so that we may successfully operate in the world? Quite evidently, we do.

Works Cited

Bennett, Jonathan. Locke, Berkeley and Hume: Central Themes. London: Oxford UP, 1971.

Dicker, Georges. Perceptual Knowledge: An Analytical and Historical Study. Dordrecht, Holland: D. Reidel Publishing Co., 1980.

Locke, John. An Essay Concerning Human Understanding. Ed. Peter H. Nidditch. New York: Oxford UP, 1975.

Abrams, M.H. Ed. The Norton Anthology of English Literature: The MajorAuthors. 5th ed., W.W. Norton & Comp. New York: 1987.

Edited by Patrick Edward Meyer.
Revised May 1,1999.