Perception and Realism


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This originally appeared in The Thought several years ago. I think it leaves something to be desired in terms of a review. Were I to attempt a review of the same book today, I'd be much more modest and probably discuss more about the perceptual process as Kelley sees it and as I understand from the studies I've done between when I first wrote this and today. I'd also do a bit more research on the various thinkers Kelley grapples with. I'm placing the review here more to spark discussion and to get people to look into Kelley's work than to sum up my views on the subject.

David Kelley's The Evidence of the Senses is a bold effort to create a consistent theory of perception from the realist camp. This writer believes it succeeds. The following brief review it's hoped will encourage others not only to read this book but to discuss its ideas.

Kelley starts off by refuting the primacy of consciousness on an abstract level. Simply put, the primacy of consciousness states that consciousness not reality is primary, that facts bend to thoughts, that reality is utterly and inescapably dependent on that which perceives it. In this phrasing, it might appear too absurd to even bother arguing with, but often it is accepted in its subtler forms. A sadly common example is cultural relativism, i.e. that the truth depends on the culture one finds oneself in and not on some external world independent of that culture.

Refuting this view is almost too easy. It presupposes its opposite: the primacy of existence, i.e. that existence is primary, that minds don't create facts, that reality is utterly and inescapably independent of its perceivers. The primacy of consciousness professes to be an immutable fact -- not a product of consciousness, but a discovered characteristic of reality independent of its perceivers. Therefore, it is inconsistent with itself, claiming facthood for itself while denying the basis of facthood. Thus it's easy to attack on this abstract and explicit level. The real danger lies with the hidden forms of this idea.

The diaphanous model of awareness is the key fallacy, he believes, in regard to all prior theories of perception. The diaphanous model views consciousness as a diaphanous medium: What's in the external world is reflected completely and without distortion in consciousness. In other words, it operates without any identity of its own. This is not only the basis of naive realism1 (the technical term for the view that perception actually occurs in this manner), but the way representationalists , skeptics, and idealists alike assume minds would have to function to actually be aware of external reality. In other words, to see one would have to see not from a particular angle or in a particular fashion but in a way independent of any means (and regardless of the conditions affecting these same means), i.e. by magic!

The theme here is, as Kelley points out, finding a way to build a consistent theory that answers the "what" and the "how" of perception: What is perceived and How is it perceived. Both the external (the "how") and internal (the "what") perspectives have never been fully integrated. This is important because the lack of integration has led some to believe that only one is real -- as in extreme materialists proclaiming mind to be an illusion -- or that no such integration is possible.

He attacks representationalism for switch-hitting on axioms (what he calls a "detente" between consciousness and existence) and for merely pushing the diaphanous model back a step into the "inner theater" of the mind. Representationalism is the view that perceptions aren't necessarily related to external objects. According to this view, one does not "see" the moon. What one "sees" is the inner representation of the moon. This inner representation is related to the external object in much the same way a painting is related to the scene it portrays. Hence, holders of this view don't believe one can perceive the external world directly, but only via these representations.

Once this step of retreating to the "inner theater" (where representations are directly perceived but, alas, these are internal) is taken there's no stopping any robust attack on its weak point: the relation of external objects to their internal representations. Since there's no evident link between the two, skeptics will readily point out, the inner theater might have no relation whatsoever to the world outside. This leads initially to skepticism and ultimately to full blown idealism -- full blown primacy of consciousness. He devotes a lot of space to examining and refuting representationalist models such as those of Descartes, Locke, Chisholm, Ducasse, Firth, and others. To go over all these theories here would go beyond the bounds of this review. This is due to the widespread influence of these models.

He takes on the various forms of idealism too, especially the linguistic idealism of the 20th century. All forms of idealism, of course, rest on the primacy of consciousness which means they are flawed at root. However, because of its recognition of the fact that consciousness does have a nature -- a trait it shares with representationalism -- idealism has been able to win a lot of adherents from Kant's time on down.2

He also examines the differences between sensational and perceptual kinds of awareness taking into account the psychological research of the last century or so3. Sensational awareness is the awareness of sensations alone without any linking to each other. This can be best described using William James' phrase "a blooming buzzing confusion." To be aware by means of sensations would be to experience the world as a kaleidoscope of unrelated and ever-changing qualities. Perceptual awareness unlike the sensational kind is the awareness of entities as such.

His position is that only under abnormal circumstances do people actually go down to the level of sensations. Perception is our normal means of direct contact with the external world and it's automatic. He presents very strong arguments against sensationalism (including the theories of Helmholtz, Hume, James, Mach and others). Sensationalism is the view that sensations are our only direct contact with the outer world while perceptions are somehow built by some conscious process (whether out of habit, computation, innate ideas, or Kantian categories) from sensations. If sensationalism were true, it would be nearly impossible to get to the perceptual level of entities as entities noted above.4

He also devotes a section to the issue of sensory qualities in which he looks into John Locke's primary and secondary qualities. Locke divided sensory qualities into two distinct categories, primary and secondary. Primary qualities included shape, number, and motion. Locke thought they were actually direct awareness of the external world's qualities. Secondary qualities included color, warmth, and pitch. Locke thought they were the result of an interaction between the senses and the external world and, in his view, a distortion of the actual traits of external objects.5

Kelley does not accept the division in the same manner and for the same reasons Locke did.6 He also thinks primary qualities are macroscopic and extensive, while secondaries are microscopic and intensive.7

His particular contribution is the idea of a "form" of perception. A form of perception is the whole shebang: the aspects of an object's appearance that are the result of the interaction between the object's intrinsic features, the means of perception, and the conditions at hand. Of course, there are no aspects of an object's appearance that are not the result of such an interaction. There are plenty of extreme examples of "perceptual relativity" (meaning the dependence of what is perceived on the specific conditions of the perceiver). One is the much talked about bent stick: placing a straight stick partially in water makes it look bent. Yet the stick is straight. The perception is not false, however. It's merely that the perceiver is perceiving the straightness of the stick in an unusual form.

He's a realist who is willing to take into account this relativity of perception. Of course, realism should necessarily entail that perceivers should be subject to the Law of Identity, i.e. that perception is by a specific means and functions in specific ways. Four other things he notes on forms of perception are: they are not objects in their own right (take away the external object and there's no longer a form to perceive it in); they are neither subjective nor in the mind -- they are the interaction; there are many different perceptual forms a given object can be perceived in (e.g., an apple can be seen in different lighting or touched); there's no such thing as a wrong perception or a wrong form (there is no right form to perceive a given object in).

He also briefly looks into the debate between foundationalist and coherence views of the structure of knowledge. Foundationalism posits that the foundations are all important while coherence theories focus on knowledge as an interrelated web, not separable into the fundamental and the derived. He believes the correct theory would incorporate both contextuality (i.e. coherence) and foundations (i.e.the nonpropositional justification by sensory perception).

Finally, the last chapter delves into the issue of perceptual judgement -- according to Kelley a form of conceptual awareness. He gives criteria for a perceptual judgement to be valid. These include that the subject must actually discriminate the object he is making the judgement about and that he must also take into account any abnormalities in the conditions of perception (e.g., poor lighting, nerve damage, illusions). This last point might seem to leave the door open for skepticism, but I should stress the subject should only take abnormalities as he finds them and not assume that since they [abnormalities] are conceivable they [ditto] are present unless proven otherwise. This is an instance of "contextual certainty".

Overall, I feel The Evidence of the Senses is a great book. If one is forced to find faults, they might be its brevity and lack of a bibliography. (Footnotes are nice, but this writer also likes the convenience of a bibliography.) It would also benefit, at this time, from an updating, taking into account the last quarter century of further research in perceptual psychology and philosophy of cognition.


1 Aristotle was a naive realist in this sense. See his De Anima, Book III, Chapter 4.

2 Linguistic idealism became extremely popular, it seems, particularly because of thinkers such as Wittgenstein, Quine, and Ryle. "They [linguistic idealists] claim...that the objects our statements refer to, the universe our discourse describes, cannot be understood epistemologically except by reference to the linguistic apparatus we employ in speaking of it." p187, Kelley, The Evidence of the Senses. "Specifying the universe of a theory makes sense only relative to some background theory." p188, Quine quoted in ibid. (It would be interesting to see Kelley enter into discourse with thinkers like Saul Kripke, who seem to have overcome the linguistic turn of modern philosophy.)

3 Kelley especially cites the work of E.J. and J.J.Gibson.

4 Since, as Hume pointed out, there's nothing in sensations themselves which links the attributes (e.g., red, cold, sweet) together to form objects (e.g., apples).

5 Locke introduced this distinction in An Essay Concerning Human Understanding, Book II, Chapter 8.

6 " seems awareness of secondary qualities first occurs at the level of sensations...awareness of primary qualities require the perceptual level and necessarily includes some awareness of secondary qualities." p113, Kelley, op. cit.

7 "...the at root...between macroscopic and microscopic qualities." p115, ibid.

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