Sunday, January 30, 2011

Materialism and the Two Existential Questions

It is hard to see the import of a metaphysical argument that has no epistemological implications. If dualism about body and mind is correct an interaction problem will have to be dealt with. By the same token if materialism is to be taken seriously it will have to provide a naturalized account of causal explanation. I take this to mean that to espouse materialism is to commit oneself to the view that a “closed” physical explanation, that is an explanation that refers only to physical causes, is possible. Many materialists understand this to mean that there can only be one “existential question,” if an existential question is one that might not have an answer: “Why is there something rather than nothing?” The idea is that there must be absolutely nothing inherently organized about the something that exists, because materialism is the bare claim that only matter exists and must accomplish everything starting from that sole axiom. Remember, too, that early modern materialism was closely linked with empiricism, forged in opposition to the classical tradition of Neo-Platonism, Christianity and rationalist philosophy and programmatically hostile to metaphysics.

Consider, for example, the argument traditionally called “the teleological proof for the existence of God” or more recently “the intelligent design argument.” Put in currently popular terms, the argument is that the complex design of the natural universe is evidence for an intelligent designer. In this context there is a significant difference between this sort of view and double-aspect theories that see mind and matter as one ontological being, under two kinds of description. (In addition to Spinoza many Hindi and Buddhist philosophers develop versions of double-aspect theory.) In so far as the design argument is an argument meant to demonstrate the existence of another being, the intelligent agent nominally responsible for the design of nature, the argument fails. The design argument starts by asserting that any finely-organized entity must have some sort of explanation. In the case of the natural world, an evidently finely-organized entity, the explanation offered is that there exists an intelligent designer. But the advocate of the intelligent design argument, in so far as he or she takes the argument to show that an intelligent designer ontologically distinct from the natural world exists, now looks committed to the need for an explanation of this finely-organized entity in turn.

To read this back into theory of mind, a materialist theory of mind has to get to mind from no-mind. The intelligent design argument fails because it is intelligence itself (in Platonic terms, the intelligibility of the universe) that we are trying to explain, and pushing the problem back a step is a failure to explain, just as saying that representations are interpreted in your head fails to explain how you, an actual person out in the world, actually interprets anything.

However, it may be that some materialists have over-reacted to the danger posed by the slippery slope that supposedly leads from recognizing that the physical universe may have some innate organization to…what? Say, full-blown Roman Catholicism? Perhaps it is simply a matter of two existential questions, not one. In addition to “Why is there something rather than nothing?” maybe “Why is the something that there is organized such that complex physical systems with formal properties arise?” To come to accept that the universe is a formally organized place can be an entirely secular resolution, after all. Materialist biologists arguing against creationism in the public schools don’t want to work themselves into an even weirder position than that of their religiously-motivated, intelligent design-espousing opponents.

The question then becomes, does accepting that there are two existential questions, not one, entail conceding that materialism is false? I think that in a way it does. If it makes sense to say that formal organization a) exists (“obtains”: I take the Aristotelean view that formal organization, if it is real, is a feature of the physical universe) and b) is a further, contingent fact (that is, there could have been a physical universe that was not formally organized to any degree) then materialism in its most orthodox version is false. I will go so far as to say that this appears to me to be the most plausible resolution to the problem of rationality, and that I do not think that it would be the end of the world if materialism were modified in this way. It is often pointed out that contemporary physics’ picture of “matter/energy” is now so strange that the concept of “materialism” probably can’t do much reliable reductive work anyway. And it is striking that physics has become more and more mathematical as the modern movement of physics has progressed over the passed one hundred years or so.

I think, though, that I can have my resolution to the problem of rationality without settling the cosmological question about the existence (or lack thereof) of innate universal order. The orthodox materialist might be able to explain how complex, self-replicating forms emerged from random, chaotic interactions, such that there is no need for “innate order.” Or materialism may fail to do this. It is enough for my thesis if formal properties are ubiquitous in worlds where rational beings evolve. How those worlds got that way is irrelevant to the point, which is that rationality is (just) another formal property and, although rational beings may be breathtaking examples of finely-formed entities, they are not therefore ontologically distinct from the rest of the physical universe.

Monday, January 24, 2011

Plato and the Metaphysical Problem of Rationality

Plato, like Kant, was reacting to contemporary currents of thought that he regarded as dangerous. He took seriously an epistemological problem that he thought was posed by Heraclitus’ doctrine of universal flux (Plato disregards Heraclitus’ view that “all things happen in accord with the divine Logos” and sets Heraclitus up as the materialist foil to Parmenides). In a world where nothing was eternal, unchanging and universal, knowledge with those qualities was also not possible: it had no object. To try to compose a description of an ever-fluxing world was like “shooting after flying game” (as Socrates says in the Theatetus). That sort of knowledge was a snapshot of a mere moment, quickly passed. Plato’s strategy for addressing this epistemological problem was metaphysical: identify the eternal, unchanging and universal object.

Plato also opposed the reductive materialism of Anaxagoras and the other Melisians, early natural scientists (Aristotle, who shared Plato’s opposition to reductive materialism, addresses Democritus’ atomism). The word “reductive” in the phrase “reductive materialism” is also epistemological in its import: the idea is that macro-level phenomena (such as the minds of persons) will ultimately be explained in terms of micro-level phenomena (such as the parts of bodies). Materialism understood this way is committed to the view that properties are caused by matter. The materialist answer to the question “Why is this property what it is?” is “Because the underlying matter is what it is.” Both Plato and Aristotle argued that causation (and thus explanation) ran the other way.

Plato and Aristotle hold respective versions of the form-matter distinction, the view that basic ontology includes both form and matter. Plato’s version is patently dualist. He holds that form is primary being, that it is mind- and matter-independent, and that formal being acts on material being such that matter can only be said to be something to the degree that it is involved in form. Aristotle, objecting to what he saw as Plato’s ontological promiscuity, argued that substance, a union of matter and form, was primary being. Among other advantages this resolved the interaction problem that afflicts Plato’s dualism. On the other hand, the price of collapsing matter and form together into substance in this axiomatic way was that one had to accept that primary being was heterogeneous. This is counter-intuitive, but that doesn’t make it wrong. Close attention to Aristotle’s metaphysical differences with Plato is rewarded with any number of insights into subtleties of the mind-body problem (for example notice the resonance with Spinoza). We will return to Aristotle and De Anima, his own great work on the philosophy of mind, in Chapter Four.

However I will argue that these differences, significant as they are, are not relevant to the present, relatively broad point I want to make about the form-matter distinction, materialism, and the problem of rationality. Ultimately I’m more of an Aristotelian than a Platonist, but I think Plato’s more explicitly dualist discussion makes this broad point best so I will discuss two passages from Plato, the “analogy of the sun” at Republic 507b-509c and the treatment of the materialist argument that “soul is an attunement of the body” at Phaedo 93a-94e.

The Sun, Plato says, makes the universe a visible place. Our eyes take advantage of this (Plato and Aristotle resisted Empedocles’ arguments for natural selection, which they saw as reductive, but the reader should join me in helping ourselves to evolutionary biology wherever it helps to fill things in here). We can see each individual visible thing because the whole universe is suffused with that one element, light, which emanates from the Sun. Analogously Plato claimed that something he called “the Good” suffused the universe with order and made it an intelligible place. The Sun is to vision as the Good is to rationality: both vision and rationality are possible because of the existence of a more general feature of the universe. Plato takes the analogy farther. The Sun’s light is necessary for the growth of plants and the Good’s order is necessary for the emergence of definite (definable, intelligible) things. The Sun is the source of warmth; the Good is the source of value. Darkness is the absence of light; badness is the absence of order.

Describe any concrete particular thing. You will describe it (you can only describe it) in terms of its properties. Concrete particulars, as Heraclitus pointed out, are constantly coming-to-be and passing away. Properties (forms, universals) are eternal. The epistemological challenge posed by Heraclitus’ doctrine of universal flux is met with the Platonic doctrine that formal knowledge (knowledge of formal properties), as distinct from material knowledge (knowledge of concrete particulars), constitutes true understanding.

However there are properties and then there are properties. I stated at the beginning of the book that I don’t like a lot of loose talk about “properties” and that ultimately I think that physical properties are the only kind of properties that there are. If I am going to qualify that at all (and at the end of this discussion you will be left with your own judgment to decide how far I have gone in that direction, and if too far), then I had better try to be a good deal more precise about what I mean by “formal properties.”

Consider two putative properties: the property of “cowness” (or “being-a-cow” or what you will) and the property of circularity. According to Plato, as matter approaches nearer to form it comes to be something, “being” meaning “being intelligible,” which to Plato is a legitimate ontological category (Plato posits degrees of being, contrary to the materialist’s zero-sum understanding of being). However, while there are certainly well-formed cows and malformed cows, even a cow still-born with deformity is a cow (if someone comes into the barn and asks, “What is that?” the right answer is “That’s a cow.”). Plato and Aristotle thought that species were fixed natural kinds (to use the standard phrase), but we (well, I) don’t think so: species are the kinds of things that come-to-be and pass away, just as individuals do. With circularity the situation is different. Being a circle just is having (instantiating) that property, and there is a threshold of trueness short of which we will say that the concrete particular isn’t a circle in a sense that it cannot be said, of any animal born of cows, that it “isn’t a cow.” Once a cow, always a cow, but a concrete particular can gain and lose the property of circularity.

The extension of the set of all formal properties can only be understood in the context of Plato’s central metaphysical thesis of the Good. Plato is clear on the difference between material being and formal being. Material being is divisible (Socrates’ body can be chopped up into pieces and scattered like leaves or burnt and blown away like smoke), it is a multiplicity (I am one body, you are another), and it comes-to-be and passes away (“All men are mortal, Socrates is a man…”). What part of reality is indivisible, a unity (oneness), and eternal?

Imagine (if this is the sort of thing that can be imagined) that one’s sole mathematical practice was to name one set, {x,x}, let’s call it “2.” Now we reflect on our named set and it occurs to us that we need a name for the constituent set, {x}, so we call it something: “1.” It is now impossible not to notice a pair of functions, “+” and “=.” From these we will inevitably get to the other functions, and we also now have a practice of naming all sets; we have the set of natural numbers. In fact all of mathematics is entailed by any part of mathematics. Mathematics cannot be cut into pieces. To have it is to have, at least implicitly, all of it, including all of those proofs that no human has as yet discovered (it is mind-independent). Nor can any part of mathematics be considered, as physical objects can, in isolation from the rest. I can imagine a universe consisting only of this desk chair floating in the vast emptiness of space (I think), but if the proof of the infinity of prime numbers is floating out there, so is all the rest of mathematics. It is one, not a multiplicity of separable propositions. Not only that, but it looks like it is floating out there, since we discover the entailments. And those proofs would be valid, undoubtedly, whether or not there was any matter and energy at all. Mathematics is indivisible, a unity and eternal.

At this point it is possible to be more specific about what a “formal property” is. I take formal properties to be mathematical properties, essentially. For what it’s worth, I even think that this may not be far from Plato’s actual theory, reflecting as it does the metaphysical influence of Pythagoras and Parmenides. To say that a thing has a formal property is to say that there is an aspect or part of that thing that can only be described in terms of mathematical or logical relationships that can be formalized without reference to the contingent physical properties of the thing. For example the property of circularity is a formal property. The set of circular things includes wooden things, clay things, bone things and metal things, but circularity is supervenient: its mathematical description is about the spatial relationship between one of its parts and another and this formalizable (mathematical) relationship does not “reduce” to any contingent properties of wood cells or clay particles etc. That is, “formal properties” are properties that can be formalized. All formal properties are supervenient on matter: there is no physical criterion that fixes the extension of the set of physical things that instantiate the property.

Another way of saying the same thing is to say that any physical object might potentially be involved in any formal property. Formal properties are universal (sometimes they are called “universals”). A critical point here is that strictly speaking there is only one formal property, that property that the universe has of being formally organized by the Good. To speak of a plurality of “forms” (“circularity,” “rationality”) is figurative. There is only one form in which all formally organized things participate; only its expression in matter is multifarious as for example in the various geometrical shapes. (In the next section I will discuss whether and how much this literalist Platonism can coexist with materialism in general and particularly with the Wittgenstein-influenced eliminativism about mental content that I sketched above.)

At Phaedo 93a-94e Socrates is responding to a kind of materialist theory suggested by Simmias. Simmias acknowledges that Socrates can raise difficulties for the identification of the soul with the body by pointing out apparently metaphysical differences between them (for example with the argument from “recollection,” which is Socrates’ term of art for innate knowledge), but Simmias argues that the soul might nonetheless be a kind of “attunement” of the body. This is an emergentist view: when all of the physical properties come together in the right way, a non-physical property emerges, not identical to but dependent on (caused by) the underlying physical properties. Emergentism is a creature of that murky area, populated by refugees and smugglers, where “non-reductive materialism” and “epistemological dualism” share a hopelessly porous border. People who wind up here wanted the goodness of materialism without the badness. Plato’s (dualist) response to the emergentist challenge provides the last link in my argument for a Platonic resolution (I don’t say “solution”) to the problem of rationality.

Consider a musical instrument and the harmonious sounds it makes. On Simmias’ view the harmonious sounds are caused by the particular physical properties of the instrument. Thus while it’s true that the harmony is not identical to the body of the instrument, it is also true that with the passing away of the instrument’s body there will be a simultaneous passing away of the harmony. Socrates responds that harmony is a formal property. That is, harmony itself is not more or less harmonic, any more than circularity is more or less circular. It is physical particulars that can gain or lose circularity, gain or lose harmony. One can get more or less harmonious, but once a lyre always a lyre. The harmony, then, is nothing particular to the lyre; the lyre may have a particular sound in some other aspect, but qua harmonious it participates in the same harmony as every other harmonious object. “Harmonious” is the type, and the extension of the set of physical tokens (musical instruments) cannot be fixed with physical criteria; harmony is formalized in musical notation.

In fact causation runs the other way. Instruments were developed (over a more or less long period of time involving trial and error) according to how well various materials, constructions, forms and so forth achieved harmony. Musical instruments come to be, and are caused to have the physical properties that they have, by virtue of the principles of harmonics. Music is a clear case where the formal property (of harmony) is the antecedent cause of the formation of a set of physical particulars (musical instruments) that exist because they participate in the property. If someone asks, “Why is the lyre shaped like that?” the right answer is, “Because that shape is harmonic.”

Here is the argument towards which I have been working: Consider the three properties circularity, harmony and rationality. They are all formal properties: they are all supervenient and they are all formalizable. The property of rationality is a very fancy formal property compared to circularity, to be sure. But rationality does not constitute, relative to circularity and harmony, any new ontological category. A circular object is an example of an object that possesses both physical and formal properties (in fact both Plato and Aristotle thought that all physical objects possessed formal properties). Meanwhile “immortality of soul” is neither more nor less than “immortality of form.” Remember that ontologically speaking there is only one form: form is a unity, matter a multiplicity. That both a rational human and a circular piece of chalk are involved in the same dualism of form and matter seems difficult to dispute.

Although Plato never, to my knowledge, uses panpsychist language to the effect that non-living objects such as pieces of chalk have souls (a view more explicit in the double-aspect ontology of Spinoza), neither does he say they don’t. Anyway he could be using the word “soul” to refer specifically to rationality and that wouldn’t affect the basic argument here. Socrates comforts his human friends with the argument that humans are constituted out of both matter and rationality, a formal property, and as form is immortal, so that element of humans will never pass away. But obviously a circular object is constituted out of both matter and circularity, and so anything said about a rational object also follows for a circular object as both are understood as possessing a formal property, and the argument turns on the immortality of form.

The result is that what we have been calling “the problem of rationality” turns out to be an instance of a quite general metaphysical problem, the form/matter problem. Now I can discuss the “resolution” to the problem of rationality that this constitutes, but first there are two discussions that are owed to those who have read up to here. The first discussion is about the relationship between the form-matter distinction and materialism: is materialism unable to give a naturalistic account of the formal properties of the universe, including the mind? The second discussion is about whether or not an eliminativist, externalist solution to the problem of representation (such as the one I proposed in the first half of this chapter) can coexist with a Platonic resolution to the problem of rationality.

Sunday, January 16, 2011

Plato is not Kant

Kant’s self-styled “Copernican revolution” was a turning inward, to the study of the mind, for solutions to the perennial problems of philosophy. Kant is, among other things, something of a reactionary. Writing at the end of the century of the Enlightenment he sought to defend Christianity, freedom and morality from the threat posed, as he saw it, by empiricism’s atheistic, amoral worldview. Particularly Kant tried to devise an antidote to Hume, and realized that Hume’s Lilliputian psychology, with its denial that anything like the “mind” could even be said to exist beyond the “impressions” caused by sensory experience, was a weak spot in the empiricist argument. Developing an ambitious account of the way the mind organized the “sensory manifold” with a conceptual framework of its own (including the “concepts” of space, time, cause and effect, multiplicity etc), Kant contained the world as understood by the new natural science within a mental representation: the “phenomenal” world was the world as represented by the rational mind, not to be confused with the actual, “noumenal” world.

Kant’s revolution has practically defined philosophy, certainly popular philosophy, ever since. From the German-language transcendental idealists, psychoanalysts, phenomenologists and critical theorists to the French-language existentialists, structuralists and deconstructionists to the English-language phenomenalists, language philosophers and, yes, cognitive scientists, it is hard to find any major philosophical movement of the last two hundred years that does not reflect the influence of Kant. He is one of the few canonical philosophers, whose influence can be seen in the views of the general public, including a great many people who have never heard of him or who do not appreciate that their own views are substantially Kantian. His message that our own minds broadly condition “how we see things” is congenial to a modern world of great cultural, ethnic and political diversity (notwithstanding the fact that Kant himself thought that the rational mind, qua rational, was the same for all).

Although Kant was engaged in a close struggle with Enlightenment empiricism his revolution was not a turning back of the clock. He presented an alternative not only to the empiricists but to the classical metaphysical tradition as well. The eclipse of explicitly metaphysical philosophy for much of the 20th century is of course due to some extent to the cultural impact of modern science, but it also reflects Kant’s core argument that psychological epistemology is first philosophy. What license have we, stuck as we are inside our heads, to make metaphysical speculations about “the external world”?

As a consequence of this it is now difficult for us to appreciate Plato, that most metaphysical of philosophers. So deeply and widely internalized is Kant’s thesis - that the conceptual order of the world is a projection from the mind onto the world - that many people simply cannot hear Plato anymore. In fact many people, even some philosophy professors and certainly a great many students, simply believe that Plato is Kant: the Platonic universals are Kant’s categories. What else could they be, when it is taken as axiomatic that the mind constructs a representation of the world? A smart student, in a typical but relatively explicit exchange, insisted that there was no such thing as the property of circularity or, for that matter, the set of circular concrete particulars: our minds create such categories out of whole cloth, apparently: and this was the view that he ascribed to Plato (he thought that he knew nothing of Kant). He was not at all impressed when I pointed to the two identical circular ceiling fans. Similarity itself, he understood, was a projection of the mind, a feature of the mental representation. As for the textual evidence (which in reality is clear and systematic), Plato is gnostic, all riddles; no one can really understand him. After all, he can’t mean what he is manifestly saying. Attempts to disabuse people of these notions, when not rejected out of hand, are met with bewilderment, anger, and various stages of grief and disillusionment. The slightly more sophisticated perceive that Plato is a bad, bad influence, putting us all at risk of totalitarian dystopia with his irresponsible foundationalism. One of my students told me that her law professor informed the class that he would have voted for Socrates’ execution.

Ah, well. Forgive this old classroom veteran my hobby-horses. Suffice it to say that, for good or ill, Plato is not Kant. Plato is making assertions about the ontology of the universe (of being); just what Kant and his followers claim cannot be done. Listening to what Plato has to say will help us to develop a resolution of the problem of rationality, at least insofar as this problem is one of the mind-body problems. I am not here trying to determine exactly what Plato the individual man actually believed in its fine points. I am not an historian of philosophy. My interest in Plato is the same as my interest in Hilary Putnam or John Searle or Jerry Fodor or for that matter the person sitting next to me on an airplane: if they have interesting ideas that inspire me in my own thinking I am grateful for the acquaintance. The reader whose principal interest is in contemporary philosophy of mind can rest assured that that is my principal interest as well, and that I am not wandering off into exegesis for its own sake. It’s just that I sincerely believe that Plato is the best exemplar of the best argument for resolving the problem of rationality.

Sunday, January 9, 2011

Spinoza and Fodor

Spinoza wrote during the transitional 17th century, when the medieval use of the term “God” as a term of art in philosophy overlapped with the early modern interest in the new science, particularly the mechanistic physics that grew out of astronomy and achieved its greatest expression in the work of Isaac Newton at the end of the century. Spinoza took a particular interest in the mind-body problem within the century’s larger preoccupation with reconciling the well-ordered, necessary world revealed by logic and mathematics with the seemingly chaotic, contingent world observed by empirical science. Philosophers of this period are often accused of hiding a thoroughly modern secularism behind religious language so as to avoid trouble with the authorities and to make their modern doctrines go down more easily, but this is a specious interpretation: these thinkers were developing modern ideas out of the old and it was a confusing and difficult process. One has to learn their philosophical language and try to understand their use of the word “God” as a technical term.

Spinoza’s core metaphysical argument is that God can have no limitations: to say that there was anywhere a boundary such that God was on one side and not on the other violated God’s property of universality (notice that one can substitute “mathematics” for “God” here with no loss of sense). Spinoza concludes that the universe (he often uses the term “nature”) is identical to God. It follows that the universe is necessary and perfect. The idea is that the causal processes of nature, seemingly full of contingency and randomness, actually unfold following mathematical necessity (in this regard Spinoza’s views are very close to Newton’s). Humans cannot see this directly due to our own limitations, but we can cultivate an attitude appropriate to the insight.

From this central doctrine Spinoza developed what is commonly called a “double aspect” theory of the relationship between the mind and the body. Everything (the universe) is both the mind and the body of God. Thus everything comes under both a mental and a physical description, which are two ways of looking at the same thing. A benefit of this view is that there is no question about either mental-to-physical or physical-to-mental causation; nor is there any question of choosing between dualism, idealism or materialism: Spinoza presents a monism where the only item of ontology is “God.” Both our mental nature and our physical nature are in fact aspects of our “Godly” (that is, rational) nature. This helps to make sense of the seemingly bizarre doctrine of “synchronicity” developed by Spinoza’s successors Leibniz and Malebranche, which expresses essentially the same idea: the mental and the physical are both explained by a common, antecedent source, which also explains how they are linked (for Spinoza they are one).

Spinoza’s metaphysics leads him to the strikingly modern position of rejecting dualist language about, for example, the mind being the controlling cause of the body’s movements (the ghost in the machine). But also Spinoza rejects the idea that the physical world (the “mode of extension”) is anything random or otherwise contingent. The physical/extended world has structure that corresponds to the mental world. His insight that fine-grained physical processes in the body instantiate the fine-grained processes of the mind (the body is “the object of the mind”) is achieved not by eliminating rationality (as Hume attempts to do) but by merging the rational and the physical.

The contemporary philosopher Jerry Fodor develops a similar line. Fodor understands that physicalism requires that the non-physical property of intentionality be washed out of the ultimate account of things, but he is convinced that mental content is ineliminable: two positions that would appear to be mutually exclusive. What account of mental representation can be given that does not involve us in reference to the semantic property? Fodor proposes to translate semantic properties into syntactic properties. The syntactic structure of the proposition (that is, of the mental representation that is implicit in the intentional attribution) maps on to the computational structure of cognition, which can be cashed out at the machine-language level. A “machine-language” isn’t really a language at all, in the sense of “language” as a symbol-system with semantic content. In the case of computers, binary code (1s and 0s) represents the physical state of the electronic gates in the microchips (open or closed). As the creators of computers we can explain the words and images on the computer screen in terms of the underlying physical process.

Uncovering the machine-language of the nervous system looks like a holy grail for cognitive science. But computers are artifacts that, ultimately, move symbols around for human beings to interpret, so the computer analogy doesn’t go through: actual mental content of the sort that (as Searle demonstrates, convincingly to my mind, with the Chinese Room) computers utterly lack has to be explained without appeal to an interpreter. The mental must be explained wholly in non-mental terms. Computers have the mental already built in: their human users. Fodor’s most expensive proposal is his idea that the causal role of mental content can be explained wholly in terms of the syntactical properties of the representation: that syntax alone can perform the function of sustaining and respecting the logical entailments between the propositions. This requires that he rejects meaning holism in favor of meaning atomism: like immune system antibodies, each mental concept must be latent and autonomous. This is also necessary if we are to keep cognitive psychology (as Fodor believes we must) “in the head.”

I have already expressed my sympathies for externalism and my eliminativism regarding mental representation. However I come not to bury Fodor but to praise him. Fodor has the same insight as Spinoza: to understand the identity of the mental and the physical requires that we understand not only the mental as, in some sense, physical but also the physical as, in some sense, mental. The problem of rationality, unlike the problem of representation, will require something like the double aspect approach. Spinoza proposes the aspects of mind and body, Fodor proposes the aspects of semantics and syntax. That Fodor is a realist about representations and I am an eliminativist does not turn out to mean that we fundamentally disagree. Specifically I don’t think that syntax entails symbol entails semantics, a line of criticism that many materialists would take against Fodor. However, while Spinoza and Fodor both point the way to the resolution of the problem of rationality, to actually get there we must now consider the metaphysics of one of the greatest of all philosophers.

Sunday, January 2, 2011

The Problem of Rationality, the Other "Problem of Intentionality"

What is the property of “rationality”? Let us say that it is a property of a rational being such that that being can make general use of an understanding of logical and mathematical functions and relationships. Rationality is a necessary component of agency (Kant stresses this): the reasons for the action can only be described with respect to the logical implications that obtain between them (and thus Kant offers a “coherence” theory of truth). Of course ultimately there are physical reasons for everything: one has to eat. “Reason is the slave of the passions,” wrote Hume, and he is right. However, the ability to grasp logical entailments is, as Chomsky, a self-styled “Cartesian rationalist” would say, “generative,” just as logical relationships are themselves non-specific. “If X, then Y.” “X.” The inference to be made from the coincidental truth of these two propositions is the same regardless of what “X” and “Y” are. Humans are able to formalize math and logic, abstracting from concrete incidents in order to be able to study these formal relationships as such. And, although my sympathy with Hume is great and my antipathy towards human exceptionalism equally so, the fact is that empiricism has a hard time dealing with mathematical and logical thought (I will use the term “rational” to refer to this kind of formal thinking for the sake of economy; in any event I think that logic and mathematics are the same thing). The kind of knowledge generated by rational thought (for example the proof of the infinity of prime numbers) appears to go beyond anything that could be explained as the product of interaction with the environment.

The idea that the propositional contents of intentional states are the bearers of logical relationships with each other is an expression of this problem: physical states and processes don’t appear to have any logical relationships whatever, whether they are “in the head” or not. However, this problem is a separate problem from the problem of mental representation, for whether one endorses a representational model of the mind or not one must still acknowledge the supervenient nature of rationality.

In fact the multiple realizability of rationality is the core metaphysical problem here. The problem can be stated this way: there do not appear to be any physical criteria that fix the extension of the set of rational beings. Flipper the dolphin, Max the Martian, Hal 2000 the intelligent artifact and I all take intentional predicates that entail the rationality assumption even though we’re not all made of the same sort of stuff. Although all four of us have physical properties sufficient to instantiate rationality, none of these physical properties are necessary for rationality (since we don’t share them). The extension of our set is indefinitely large.

A common popular view is that emotional experience and feeling are what make the naturalization of psychology so difficult, but philosophers and psychologists from the ancient Greeks on have more frequently taken humans’ rational capacity as the principal warrant for dualism. In fact both of the two greatest rationalists, Plato and Kant, saw emotions as fundamentally physical in origin, “passions” of the soul (like hunger) that sprang from our contingent natures as physical things. Plato and Kant also agreed that the capacity for rational thought was the key to human freedom, which they defined as freedom from the coercion of physical cause-and-effect relations. Both thought that qua embodied beings humans were mere material things, but through participation in transcendent rationality humans became (or could become) more than mere things.

I doubt that being motivated by purely logical thoughts (whatever that would be like; I suspect it’s inconceivable: and see Chapter Four) would result in anything recognizably like our usual conception of “freedom.” After all logical entailments follow necessarily from their antecedent propositions, so that to the extent that one is motivated by purely logical considerations one does not experience choice (or possess any psychological individuality for that matter). But putting the question of freedom aside, it does look like emotional experience is part of consciousness (emotions are essentially phenomenal) whereas rational thought is part of intentionality. Anyway that view, and the view that phenomenal “properties” of mind are, ontologically speaking, identical to physical properties of the body, will be defended in Chapter Three.

It turns out that understanding a difference between Plato and Kant is the key to the resolution of the problem of rationality when viewed as one of the mind-body problems. Before elaborating that difference, however, it will be useful to lay some groundwork by considering the views of two other great rationalists.