Hsieh on Searle on Reductionism

 Posted by on 30 November 2002 at 12:26 pm  Uncategorized
Nov 302002

I recently finished reading John Searle’s seminal book on philosophy of mind, The Rediscovery of the Mind. Perhaps most delightfully, the clear and engaging arguments in Searle’s book were a welcome respite from the overabundance of boring and convoluted articles assigned as reading for my “Philosophy of Mind” class. (I don’t fault my professor for choosing such articles, as they are the “classics” in the field.) Unfortunately, I don’t find much hope in Searle’s positive account of the mind as a “causally emergent property” of the physical organism (Searle 112). As my professor (Bob Hanna) has noted, accounting for mental causation (let alone free will) may well be an impossible chore within Searle’s model of consciousness. Nevertheless, Searle offers a number of compelling arguments against various wrong theories of mind, particularly against reductionism and functionalism. While I hope to address the Searle’s complex argument against functionalism in the future, his argument against reductionism shall be the topic of the day.

In Chapter 5 of The Rediscovery of the Mind, Searle first defines the fuzzily-used concept of reduction as “the idea that certain things might be nothing but certain other sorts of things” (Searle 112). Thus water could be reduced to H2O molecules if and only if water were nothing but H2O molecules. Searle then goes on to distinguish five types of reduction: ontological reduction (objects of one type are nothing but objects of other types), property ontological reduction (properties of one type are nothing but properties of other types), theoretical reduction (the laws of one theory be deduced from the laws of another theory), logical/definitional reduction (statements about one type of thing can be losslessly translated to statements about another type of thing), and causal reduction (the existence and causal powers of one type of thing are entirely explainable in terms of the existence causal powers of another type of thing). For Searle, ontological reduction and causal reduction are most relevant to modern debates about the mind, given that ontological reduction is the goal of serious reductionists, while Searle advocates only causal reduction.

Searle’s theory of the mind advocates causal reduction in that “mental features are caused by neurobiological processes” (Searle 115). In the history of science generally, Searle argues, such causal reductions quickly lead to ontological reductions because “we simply redefine the expression that denotes the reduced phenomena in such a way that the phenomena in question can now be identified with their causes” (Searle 115). For example, while we used to think of the color red as merely a type of subjective sensation, through the development of science, we came to “carve off and eliminate the subjective experience of color from the ‘real’ color” understood as “light reflectances” (Searle 115). Thus the ontological reduction of color naturally flowed from the causal reduction of color.

However, Searle argues, consciousness does not follow this same pattern of first causal and then ontological reduction (Searle 116). A complete causal reduction of pain, for example, to neurophysiological processes, would leave out “the essential features” of pain as an “unpleasant conscious sensations” (Searle 117). But why would this be so? Why is consciousness so unique? Searle argues that ontological reductions seek to “carve off the surface features” of something so as to redefine that something “in terms of the causes and produce those surface features” (Searle 119). Thus we might reduce the mass of a pile of iron filings to the mass of an individual atom of iron multiplied by the number of iron atoms in the pile because the mass of the whole is completely explained by the mass of its constituent parts.

In early scientific understandings, where “the surface feature is a subjective appearance” like color or heat, we perform the reduction by “redefin[ing] the original notion in such as way as to exclude the appearance from its definition” (Searle 119). Thus color is reduced by excluding the subjective sensations of color from the definition in favor of talk about “light reflectances” (Searle 119). And heat is similarly redefined in terms of “the kinetic energy of the molecular movements” to the exclusion of any discussion of feelings of warmth and coolness. Such reductions are possible because we are primarily concerned with the “underlying physical causes of heat” rather than the “subjective appearance” of heat (Searle 120). But we should remember that this sort of reduction by redefinition does not involve any sort of eliminativism about subjective experiences, as those subjective experiences “exist the same as ever” (Searle 120).

So why can’t we perform such reductions with mental states like pain? Searle argues that in fact we could, but that they would leave “the subjective experience of pain unreduced” in the exactly same way that “the reduction of heat left the subjective experience of heat unreduced” (Searle 121). Such a situation is acceptable for heat, given that “what interests us about heat is not the subjective appearance but the underlying physical causes” (Searle 120). In contrast, the subjective experience of mental states like pain are precisely what we are so keenly interested in understanding. An ontological reduction of mental states therefore cannot offer us the sort of knowledge of the mind we seek. As we have seen in the history of reductionist accounts of the mind, consciousness would be left unexplained by an ontological reduction.

While I am in broad agreement with Searle’s argument, I do have two objections on Objectivist grounds.

First and foremost, Searle uses the ever-so-Kantian appearance-reality distinction to summarize his objection to the ontological reduction of the mind. He argues that ontological reductions carve off the “appearance” from the “reality” of something, but that such is not possible for mental states because “consciousness consists in the appearances themselves” (Searle 121-2). Thus, he summarizes: “Where appearance [or consciousness] is concerned we cannot make the appearance-reality distinction because the appearance is the reality” (Searle 122).

Searle’s argument, however, cannot be anything but superficially Kantian given that it can easily be understood in light of the form-content distinction found in Objectivist accounts of perception (such as David Kelley’s The Evidence of the Senses). The “content” in perception is simply whatever features of the world stimulate our sensory system. The form, on the other hand, is the “aspects of appearance that result from the way our sensory systems respond to stimulation” (Kelley 42). In perception, the form and content are inextricably linked, such that colors look to be in the objects themselves, for example. But through scientific inquiry, we learn that color is the form in which we perceive the reflective qualities of surfaces. Similarly, we learn that heat is the form in which we perceive the kinetic energy of molecules and that pain is the form in which we perceive tissue damage. Consequently, we are able to conceptually separate “the way in which we perceive external objects” from the intrinsic properties of those external objects themselves (Kelley 42). Thus Objectivism rejects the Kantian gap between “appearance” and “reality.” Rather, the appearance of an object is simply our awareness of that object in a given form, as dictated by the nature of our perceptual systems. All awareness must be in some form or other — and no form of awareness is more “real” than any other. (Ayn Rand’s own brief comments on the form-content distinction are found in a discussion of the false distinction between primary and secondary qualities in the Appendix of Introduction to Objectivist Epistemology, pages 279-282.)

Searle’s argument can, in fact, be easily reformulated in terms of this form-content distinction instead of his appearance-reality distinction. On such a reformulation, the ontological reductions we find in science are actually attempts to distinguish the form from the content of our perceptions, i.e. to distinguish those aspects of perception that are intrinsic to reality (content) from those are the product of the perceiver’s relationship to reality (form). However, in studying consciousness per se, the form cannot be identified and sidelined through ontological reduction, since the form of perceptions and other mental states are precisely what we are interested in explaining.

My second (and final) objection to Searle’s argument against ontological reduction of mental states concerns his division between concepts that can be ontologically reduced (like color and heat) and concepts that cannot (like pain). Searle certainly admits that this distinction is based upon our “definitional practices” rather than on “any distinction in the structure of reality” (Searle 123). I think there are two good reasons to doubt those definitional practices themselves.

First and somewhat superficially, there seems to be no principled divide between allegedly reducible concepts like color and heat on the one hand and irreducible concepts like pain on the other, as all have both phenomenological and causal aspects. If we are interested in the phenomenology of color and heat, as many philosophers and scientists now are, then ontological reduction of those concepts is impossible without omitting precisely what we wish to explain, as in the case of pain according to Searle. On the other hand, if we are uninterested in the phenomenology of pain, we can reduce pain to the detection of tissue damage in the exactly same way Searle reduced color and heat. (A surgeon, for example, might be concerned with what a patient’s pain indicates about hidden tissue damage rather than how much it hurts.) Consequently, the possibility of ontological reduction seems to be solely a function of our interest — or lack thereof — in the phenomenological aspects of a given concept.

Second and far more significantly, the process of ontological reducing concepts of perceptions to their causes is not, as Searle indicates, a process of overturning or redefining those concepts at all. Rather, such ontological reduction is a process of either adding new knowledge to our existing phenomenological concepts or of creating entirely new (albeit related) casual concepts. Scientific investigation of the world shows us, for example, that differences in colors are caused by differences in the reflective properties of surfaces. For most of us, that knowledge merely serves as an adjunct to our essentially phenomenological concepts of color by helping us conceptually differentiate between the form and the content of color perception. For scientists, that knowledge may in addition justify the formation of a new concept of the reflective properties of surfaces also (and somewhat unfortunately) called “color.” But in neither case are the phenomenological concepts of color overturned, replaced, or redefined. After all, although we may conceptually distinguish between the form and content of our perception of color thanks to science, we continue to subjectively experience color as a unity of that form and content. And when a scientist tells his child that the crayon “looks more blue than purple to me,” he’s referring to his subjective experience of those colors, not readings on some sort of lightwave meter. That only one word is used ought not confuse us into thinking that there is only one concept!

My second objection to Searle’s critique of reductionism actually seems to give us all the more reason to reject reductionistic accounts of consciousness — by indicating that genuine ontological reduction is not possible with any phenomenological concepts at all. Rather, in light of science, we tend to either add information to our essentially phenomenological concepts or form new concepts that ignore the phenomenology in favor of the physical causes. Either of these processes is fine and dandy, so long as we understand that we have not reduced our phenomenological concepts to physical concepts.

As a side note, my anti-reductionistic view agrees with Rand’s comments on concepts of sensations in Chapter Five of Introduction to Objectivist Epistemology:

Sensations are the primary material of consciousness and, therefore, cannot be communicated by means of the material which is derived from them. The existential causes of sensations can be described and defined in conceptual terms (e.g., the wavelengths of light and the structure of the human eye, which produce the sensations of color), but one cannot communicate what color is like, to a person who is born blind. To define the meaning of the concept “blue,” for instance, one must point to some blue objects to signify, in effect: “I mean this.” Such an identification of a concept is known as an “ostensive definition” (Rand 40-41).

Rand’s first sentence strikes me as a particularly insightful explanation of why phenomenological concepts cannot be reduced.

All in all, I think that Searle’s argument against reductionism shows why the various qualia arguments against reductionism seem plausible to us. All of those qualia arguments (the absent qualia argument, the inverted qualia argument, the gap argument, the knowledge argument, and so on) are designed to pump our intuitions into telling us that reductionism does not adequately account for phenomenology. Not being one to trust my intuitions, these arguments carry very little weight by themselves. But Searle’s argument shows that omitting phenomenology is precisely what reductionistic accounts do. As such, a reductionistic account of consciousness is impossible.

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