What Are "Intentional States," Anyway?

I'm traveling with my family, going out on a boat on the Delaware River tonight with all of my mother's sobrinos, but can't resist a nice basic question.
Billie Pritchett asks, "Do you think intentional states are natural kinds?" I think that an underlying kind of big question is what "natural kinds" are, I for one don't know, Aristotle thought that individual things were primary being and that natural kinds were ineliminable categories of those, species being his paradigm example. Plato thought that logical relations, such as are described in mathematical proofs, were "universals," which were the-most-interesting-being, anyway, so far as he was concerned. I think that this metaphysical discussion lies at the heart of functionalism and in general for the philosophy of mind. In fact my interest in metaphysics grew out of my interest in the metaphysics of mind. If, in addition to the existential fact that something exists rather than nothing, it is a different (contingent) fact that the universe is formally organized, if there are two existential questions instead of one, then "materialism" is false. Progress is to see that on this view the mind/body problem is not a particular problem in metaphysics, rather it is just an instance of the more general metaphysical problem. That looks like a little bit of resolution for the mind/body problem, at least as to the metaphysics of intentionality.
So getting more focused on your question, it is my view (the short answer is) that intentional states are ineliminable. But what are they? (You see that metaphysics is a matter of taking your assertions seriously.) My (admittedly circular) claim is that something is a person to the extent that it takes intentional predicates (a jargon way of saying that we use belief/desire psychology to explain and predict its' behavior). It looks to me that humans, some (actually I think many) non-human animals, possible aliens and possible artifacts can all be (equally) persons, so I conclude that intentional predicates aren't tied to any specific matter or even any specific kind of organization of matter (note that the problem of phenomenal properties requires a whole separate treatment here).
I think that intentional descriptions are descriptions of relations between the person and the environment. This is the connection between my views and behaviorism, also "wide-content" (externalist) accounts, and of course my interest in Wittgenstein. I don't know if relations are properties ("relational properties"), maybe not (John Heil says no). Certainly the whole discussion of "properties" is just as inchoate as the discussion of "natural kinds."

Behaviorism and the Mereological Fallacy

Gerardo Primero is interested in the question of whether or not intentional predicates applied to brains are meaningful. His idea is that there is a difference between saying something that is meaningful, but wrong (his analysis), and saying that such predications are nonsense (devoid of meaning). His take on Wittgensteinian analyses (such as that of Bennett and Hacker in Philosophical Foundations of Neuroscience) is that they claim that e.g. saying that there are images or sentences or other forms of representation "in the brain" is meaningless. So the question is whether or not Gerardo has a good criticism of Bennett and Hacker in this regard.
Note that this discussion is to a large extent a version of the oldest and biggest problem for behaviorism, that is that we have strong intuitions that phenomenal experience is distinct from outward behavior, as in the case of the man who pretends he is in pain when he is not. Surely this exposes behaviorism as incomplete at best, if the behaviorist claims that "Sally likes chocolate" does not entail a reference to the quality of her gustatory sensations when she puts the chocolate in her mouth? Daniel Dennett is trying to untangle this in The Intentional Stance (unsuccessfully, I think), and David Chalmers in The Conscious Mind takes the alleged possibility of "zombies," operational duplicates of conscious persons who have no conscious experience, as grounds for metaphysical dualism about "phenomenal properties" (spuriously, I think).
But today I want to stick to Bennett and Hacker's theme of the "mereological fallacy," the fallacy of attributing to parts properties had only by the whole. I'm not myself too wedded to the idea that B & H hold that committing the fallacy is equivalent to "nonsense," maybe they just think it's unhelpful, or vacuous; but I want to write more generally today.
Gerardo writes, "People do ascribe mental terms to things that are not persons (i.e. to corporations as in 'Microsoft believes that...,' to machines and robots as in 'it sees and recognizes visual patterns,' to brains and brain parts, to animals), and people usually understand each other..." The definition of a "person," it seems to me (and I am making no effort to defend or even necessarily represent B & H here) just is "any being that takes intentional predicates," I take that to be the idea of operationalist approaches.
Viewed in this light, Gerardo's list of examples turns out to be quite heterogenous. Long-time readers of this blog (are you the one?) know that I take animals to be paradigmatic examples of persons: dogs, say, believe and desire and hope and fear etc., and the semantics of those predicates are the same, on my view, when applied to humans and to dogs and many other non-human animals (contra Davidson, by the way). Similarly with possible conscious androids: as a materialist, since I am committed to the view that human consciousness is a feature of physical properties that humans possess, ipso facto an artifact that had those properties would be conscious (but computers ain't it; the relevant properties are not merely computational - John Searle gets this right). Corporations are a stranger example (remember Ned Block's Chinese nation example), and I'm not sure what I think about that: my intuition is pretty strong that animals and possible conscious artifacts are conscious as bodies (I'm pretty sure I have a physical criterion of personal identity), and that a "being" composed of unconnected parts maybe could not have consciousness in this (admittedly vague) sense. Still, a corporation, or nation, or team, is after all a kind of body, so there is at least room for discussion there. So "brains and brain parts" seem to be the odd man out on the list.
Years ago when I first heard about functionalism my first naive response was "But persons don't have any function!" Maybe that's right: the person is an embodied being with preferences and aversions. (Are the values a hard part for the possible conscious artifact? Maybe yes.) I'm thinking about the difference between the telos of the car battery (starting the car) and the telos of the car (driving people around). You might say that all there is is just nested functionality, all the way up and all the way down (I read William Lycan this way). If that's how you see it, then maybe car batteries and brains have as much claim to personhood as cars and humans. Dennett says that a thermostat comes under intentional description: it believes that it is presently too cold, or that it is not. On this version of operationalism the only problem with saying, "My car battery doesn't like the cold weather" as a further explanation of my claim that "My car doesn't like the cold weather" is that there is some (informal) threshold of obtuseness when it's just not necessary anymore to replace physical predicates ("It's frozen") with intentional ones ("It's unhappy"). And maybe that's right.
What I take B & H to be claiming is that there are no neural correlates of intentional states. There is not some brain state that embodies my belief that Paris is capital of France, or my desire for some chocolate. That is the sense of the mereological fallacy: that it is a mistake (a mistaken research paradigm) to search for neural correlates of intentional states. This goes to my problem with representational models of mind. It doesn't help to explain how it is that I believe that Paris is the capital of France to claim that there is some formal token of the proposition "Paris is the capital of France" inside my body somewhere. I don't think that intentional states are neural states at all. I think that they are states of embodied persons. What kind of "states"? (John Heil does good work on the metaphysics of "states," "properties," and so on.) Right now I'm thinking that "intentional states" are relations between persons and their environments (this is a type, I think, of externalism/"wide content").
Anyway I'm off to do the recycling and sign my daughter up for swimming lessons.

Anomalous Monism is Neither. Discuss Amongst Yourselves.

Kevin Vond left a comment on the last post (discussion with Gerardo Primero) and mentioned Donald Davidson's article "Mental Events," which got me thinking this morning. I think that Davidson is, in basic metaphysical terms, the very opposite of the sort of eliminativism that I am discussing: eliminativism about symbolic content playing a causal role in the functioning of the nervous system, on a reasonably well-naturalized model of nervous system function. And I think that Davidson is guilty of the mereological fallacy.
Davidson's view in "MEs" is that he can simultaneously hold that metaphysically speaking intentional states and causes just are identical with neural states and causes (or, intentional properties supervene on neural properties), and meaning holism, the view that parts of language have meaning (are interpretable)only within a larger context of an entire language and the web of intentional states that are also being attributed to a particular person. Thus the "anomalous" part is that there can be, according to this "anomalous monism," no "psychophysical laws," nomological rules for mapping back from the neural processes to the intentional processes.
Thus brain states, according to Davidson, just are intentional states under a different description (and I see where Kevin picks up on the Spinozistic side of this). This is precisely the view that Wittgenstein opposes. Davidson locates all of the causal power in the linguistic and logical relations between propositional attitudes (beliefs, desires, etc.). These attitudes are individuated in terms of their propositional content. This is sometimes called a "sentential" model of mental representation, involving as it does sentences, understood as tokens of propositions, in the head. It's more useful to call it a formal model: formal representation and supervenience on physical processes go together. This intentional realist camp includes Descartes, Kant, Chomsky, and Fodor as well as Davidson.
I think that this may be all wrong (I think that representational models of mind may be all wrong), on the basic grounds being discussed in the last post. Note also that elsewhere Davidson ("Thought and Talk") argues that non-linguistic animals can't have intentional states, because intentional states are propositional attitudes. Thus the subsequent interest in whether animals could learn grammar. This is Chomsky's view as well, at least the early Chomsky would argue that animals could not think (he's more liberal on that now). Of course that is backwards, thought precedes talk by a very long way. Understanding sea slugs is indeed a big help.
PS Kevin and Gerardo, "Discuss Amongst Yourselves" is a reference to a popular humor show in the US, just a joke!
(Also thanks and a tip o' the hat to Brood's Philosophy Power Blogroll for the shout-out.)

Is Your Brain Somebody?

Gerardo Primero, a psychologist in Buenas Aires, has been corresponding with me via e-mail. He is studying Wittgenstein and wanted to talk about Bennett and Hacker's 2003 book Philosophical Foundations of Neuroscience. That book takes a Wittgensteinian approach (P. M. S. Hacker is one of the leading philosophical interpreters of Wittgenstein) and builds an argument that a great deal of cognitive studies makes some version of the "mereological fallacy," the fallacy of attributing to the parts of a thing properties that are had only by the whole. Specifically "persons," who are full embodied beings, think, dream, desire, imagine, and so forth, whereas much philosophical psychology attributes these intentional states to brains, to consciousness, to memory, and so forth. The idea is that just as I eat lunch, not my stomach, so too I think about the election, vs. my brain. Note that if this turns out to be right, that psychological predicates are applied to persons and not to brain states, then the metaphysical problem about how the physical properties of the nervous system "map on" to the semantic properties of the representations may be shown to be a pseudoproblem, in that intentional psychological descriptions just aren't descriptions of states of the brain. Mind does not necessarily = brain.
Let me quote a little from Gerardo's e-mail from Sunday: "I'm not convinced by Hacker's arguments....The problem with the 'mereological fallacy' is not that applying psychological terms to parts 'has no sense': it has sense, but it's scientifically unsound...While my argument is epistemic ("that's not a valid scientific explanation"), Hacker's argument is semantic ("that has no meaning at all").
There are a lot of directions we could go with this, but since Gerardo seemed to approach me for maybe a "philosopher's opinion," I'll talk some basic metaphysics and epistemology this afternoon. The issue is metaphysical, to my eye: there is a language about "properties," and so we want to get clear on what properties are, because it looks like we would need to do that to understand how the brain works (properties are causal). Specifically the "property" of interest in terms of the mind/body problem is the "intentional/semantic property." What is this? That bears some discussion, but note a basic issue: if you think that the semantic property is a property, but it's not a physical property, then you have signed on to some kind of metaphysical dualism. Descartes thought this way. He thought that any physical thing, being ultimately a mental representation, had the property of dubitability (could be unreal, an illusion), whereas the fact of thinking (of a "thinking substance") was indubitable, and this is one of his arguments for metaphysical dualism (sometimes called "substance dualism"). Disparate properties, disparate things. Which is fine, maybe, but recognize the committments that come with such a view: a) there are "things" that exist that are not part of the physical universe, and b) therefore, in this example of the more general metaphysical point, scientific psychology is impossible. I don't buy that. That is, I think that humans are part of physical nature through-and-through. And if "physicalism" means anything, it's got to mean that everything about humans that we can "explain" (whatever explanation is) we can explain in physical terms (just like the rest of nature). So a naturalist like myself has two options: 1) Try to understand "mental representation" and thus symbols and meaning in general in some kind of physical terms, or 2) try to eliminate representational content from the model of mind.
So, as to Gerard's distinction between "meaningful" and "explanatory," I would say that physicalists (we could here say materialists or naturalists, I'm not making any fine distinction) who are eliminativists (like Wittgenstein and Skinner) think that to the extent that "meaning" is not the same thing as "causal power" there isn't any such thing. Think of a behavioristic, anthropological account of the development of speech: the latter-day "semantics" of the words emerged out of the functional role of making that sound. It isn't true that all words function in the same way (that is, as symbols). This is what Wittgenstein means with the analogy of the locomotive controls: they all fit the human hand, but one opens a valve, one puts on a brake, etc.; it is a mistake to try to explain them all the same way.
If you can't explain the "mental" property without including something "mental" in the explanation, then you haven't explained mind. An "explanation" of mind would be the story of how semantic properties emerged from simpler, non-semantic properties. Mind from no-mind. So a problem with representations is that they already assume mind. Semantic content needs an interpreter. Or, the story about how something came to "mean" something can't already assume that "meaningfulness" exists - if you have to do that, you haven't succeeded in naturalizing the concept of "meaning."
There is a contingent who want to develop a natural theory of information. I would recommend starting with Fred Dretske's Knowledge and the Flow of Information. For myself, at this point I feel pretty convinced that there can't be any such thing as mental content, at all. Just wrong, root and branch. But note that there is a representational vogue underway amongst the cognitive scientists (or was two years ago).
Looked at this way, one can see that the problem with attributing mental states to brains isn't, I wouldn't say, meaningful but wrong (as Gerardo argues), but in fact not meaningful. They are pseudoexplanations because they don't turn out to even potentially explain anything: they're not even wrong. "When I remember her face, I have an image of her face." "I just gave myself a dollar." Both examples of the same mistake.
Finally for today, Gerardo wanted a little more on Wittgenstein vs. Moore. Moore tried to argue from "usage," that is, he argued that the claim "I know I have a hand" was a paradigmatic case of knowledge. Wittgenstein objected (in On Certainty) that there was no ordinary circumstance in which holding up one's hand and saying, "I know I have a hand" could have any purpose. W.'s point was that Moore made the mistake of continuing to play the game that was the cause of the confusion in the first place. In fact I neither know nor do not know whether I have a body; that's not really an example of a situation where the verb "to know" can serve any function.

Hume's Naturalism

If claiming to be a "naturalist" means anything at all, it must mean that one is some sort of metaphysical monist; put the other way around, if "nature" just refers to whatever exists, metaphysically heterogenous or not, it is a vacuous term.
Hume says, "For as to the notion of external existence, when taken for something specifically different from our perceptions, we have already shown its absurdity" (Treatise 1.4.2, Of scepticism with regard to the senses). Before we follow this reference, note that Hume is not, as commonly supposed, some sort of happy sceptic, whose empiricism entails codifying Cartesian scepticism as irrefutable. Very much to the contrary, Hume takes the much more ambitious position that Cartesian scepticism is a pseudoproblem, based on misunderstanding. The very idea of a distinction between "external existence" and "perception" is absurd. Thus the idea that we are "stuck inside our heads," unable to see around our "mental representations," is absurd. The representational theory of mind itself is an absurdity. And if this interpretation of Hume bears textual scrutiny, as I think it does, the whole main trunk of Hume interpretation, sympathetic and hostile, of the past 250 years is spurious root and branch.
This absurdity is shown, Hume claims, at 1.2.6, Of the idea of existence, and of external existence. "Now since nothing is ever present to the mind but perceptions, and since all ideas are deriv'd from something antecedently present to the mind; it follows, that 'tis impossible for us so much as to conceive or form an idea of any thing specifically different from ideas and impressions." This is Berkeleyan. Berkeley, who seems so bizarre to generations of undergraduates who are simply presented with his idealism without enough context, is basically a competent philosopher trying to clean up a mess: if we can't make our way from the "properties of the things-in-themselves" and the "properties of experience," granting that experience is what we have, let's go with experience and leave it at that. A thoroughly empiricist solution to be sure. But not one that warrants the bizarre (Cartesian) metaphysical interpretation to which Berkeley is commonly subjected. The point rather is that the whole discussion, from Descartes to Locke, is a mistake. It is meaningless to talk about some "reality" beyond the reality of experience. This (one must repeat the point to have any chance of overcoming centuries of indoctrination) is not at all the same as saying that there is an external world to which we do not have access, trapped as we are within our experience. "The world," understood in any meaningful way, refers to the world of experience. It is literally inconceivable that there might be a world distinct from experience, or experience distinct from the world. Technically the position is nominalist: "the world" is the name of the category of all experiences. And on that point, Hume, in a footnote to 1.2.6, explicitly refers us to a citation of Berkeley: "A great philosopher (Berkeley)...has asserted, that all general ideas are nothing but particular ones, annex'd to a certain term, which gives them a more extensive signification, and makes them recal upon occasion other individuals, which are similar to them" (1.1.7, Of abstract ideas: the "external world" is an abstract idea of this kind).
The idea is common to scholars of Buddhism. Dogen, the classical sage of Zen, says that experience (the mind) is "the blade that cuts, but does not cut itself." The mind cannot perceive itself (Hume: there is no "self" other than experience itself). Thus there is no Cartesian mystery as to "the world-in-itself" vs. "the world as I experience it." When the distinction breaks down, both sides of the Cartesian dilemma vanish simultaneously: it is equally absurd to refer to "representations" as it is to "mind-independent reality."
I have to go to K-Mart to buy a laundry basket and a dish-drying rack, and take a comforter over to my mother-in-law's house (speaking of reality). Final chunk of argument for this afternoon: it turns out that perceptual states, on Hume's view, are not "copies" of external reality (this has been shown to be absurd). Rather they are states of the body. That is, there is no metaphysical distinction between the mind and the body. It is true enough that when we talk about our "perceptions" we are talking about states of our own bodies; this need not involve us in the concept of "representation." And here's a remarkable outcome: this is Spinoza's view as well.

Hume's Value Naturalism

The Hume Society has chosen the topic of "naturalism" for the 2009 conference, and since a) I think I've got a line on naturalizing Hume's ethical theory, and especially since b) the conference is to be held in Halifax, Nova Scotia in August, my project this week is putting a submission together (not that that's an easy thing: if you check out their journal Hume Studies you'll see that these are indeed the preeminent Hume jocks, and a wonk I am not, although I've been a member for some years. But it's in Halifax so I have to give it a whack). So it's Saturday and I'm done with the kitchen and now I'll try blocking out the basic line here.
As most of my readers will know, Hume's best-known claim about ethical theory is that one cannot derive an "ought" from an "is." That is, descriptive propositions about the world do not as such contain any prescriptive meaning (it's important to remember that Hume is talking about propositions). Imperative prescriptions are motivated rather by "moral sentiments," non-cognitive feelings with which we have been endowed by nature, Hume knows not how. I think that Hume would be satisfied with Darwin's subsequent account of the etiology of ethical response. In fact Hume not only neatly flags the missing explanation, but asserts that the question is one for natural science, not philosophy (today I'm not going to provide any citations or passages, this is just off the top of my head). Part of Hume's bigger-picture agenda here is to debunk rationalist approaches to ethics, which the "schoolmen" took to involve ethics in transcendental metaphysics (Plato, by way of 17th century rationalism): Hume denies that ethical thinking is a branch of logic.
On my view, the most important thing to get about Hume is that he was not a skeptic, as is widely expounded. Rather Hume saw Cartesian skepticism as a pseudoproblem, and empiricism as the way out. Later the English phenomenalists of the early 20th century obscured this and now, with the aid of Wittgenstein, we are reconstructing Hume. Specifically Hume's is/ought distinction is frequently confounded with G. E. Moore's "naturalistic fallacy," which in fact is a very different sort of argument than Hume's. So if I can articulate the Humean critique of Cartesian skepticism, and show how Hume's is/ought distinction fits into that critique, this would help to nail down a persuasive account of Hume as a kind of naturalist about value.
Central to this is Hume's denial that it made any sense to speculate about an "external world" that might or might not be "corresponding" to the world of our perceptions. Experience cannot be distinguished from the world, and the world cannot be distinguished from experience. Thus there can be no question of "phenomenal properties," since any discussion of phenomenal properties is necessarily a discussion of experience, and any discussion of experience is necessarily a discussion of the world. There is no sense in which "my experience of blue" is different from "blue." To use Hume's language, mental contents consist of impressions and ideas, "impressions" being directly caused by interaction with the environment, "ideas" being fainter versions of impressions conjured by the mind during thought (e.g. memory).
The problem in interpretation of Hume's ethical theory is that often even people who grasp the anti-phenomenological import of Hume's empiricism don't interpret his ethical theory in a way that is consistent with his epistemology. When Hume says that there is no way to derive propositions about causality from propositions about correlation, or propositions about personal identity from propositions about self, he is saying no more nor no less than when he says this about propositions about value and propositions about fact. The is/ought distinction is simply another variation on the general theme that there is no need (no possibility) of "theory" over and above what is given by experience. And values (or rather, goodness and badness) are as much a given of experience as are causal relations and self-awareness. Thus Hume is not a "subjectivist" nor a "relativist" about ethics. In fact one of his targets is systematizers, for example of the religious variety, who claim that ethical responses are produced by embracing their systems, a form of cognitivism. The goodness and badness of experience is no more subjective or relative than is the blueness and redness of experience. On Hume's view there simply is no distinguishing between the "mental representation" and the "fact," and there are no exceptions to this general truth. Thus there is nothing to be said about "mental representation" nor about "facts," if either of these are taken to be somehow distinct from experience. Subjectivism is just as vacuous as realism on Hume's view.
Finally, notice that this is a general account of value, ethical and aesthetic. Arguing for the moral rightness of something is not different from arguing for the beauty of something. While we may feel queasy about this, realizing that the quality of experience is not always intersubjectively consistent, this is how it goes; there is no logical proof or refutation of the quality of experience. That does not mean that someone cannot learn to appreciate the goodness or the badness of something.

Which Animals Have Minds?

Some of us (OK, I) have an intuition that dogs, say, are accurately described as having beliefs and desires, but crickets, say, are not. What about carp? There seems to be a threshold problem. How do we fix the set of beings that come under intentional psychological explanation? On a Wittgensteinian view this is not a problem, because psychological descriptions are necessarily descriptions of publicly observable phenomena. Like life, consciousness is either there or it is not. There is the well-worn objection that it is at least conceivable that there could be a being that behaved as if it were conscious, but that was not. David Chalmers, for one, has built an entire philosophical position on this claim, so debunking it would be significant. Wittgenstein's response is interesting if perhaps not knock-down: he suggests that in fact such a being is not conceivable, that we are confuting reference and use when we say that it is (we can name a round square, but we can't conceive one). As with many of Wittgenstein's arguments, this one seems awfully fast. Still, I feel its pull: for example, I suspect that a disembodied mind is actually inconceivable, even though people claim to be conceiving of them all the time. Reading the Investigations, it may be that Wittgenstein is more interested in the property of "being alive," as a property that he might take seriously, while he may be more skeptical about the claim that "having a mind" is a property at all.

A Problem for Evolutionary Psychology

I've just sent off my chapter "Real Behaviorists Don't Wear Furs" for Nandita and Vartan's book Animals in Human Signification or something like that, and I have two little chunks of argument that emerged this morning pursuant to that, I'll split them into two posts, this one and the next.
There is a mistake, I think, in the premise of evolutionary psychology. According to a strong version of this view, adaptationist explanations of behavior (explanations that appeal to the fitness-conferring value of various behaviors) replace intentional explanations (explanations that take intentional states to be causal, as in, "He went to the river because he wanted some water"). (Let me note in passing that to whatever degree evolutionary psychology is a valid way to explain behavior, it is equally valid when applied to humans as when applied to other species; the evolutionary psychologist has no grounds for claiming that humans have "minds" while other species do not. But that is not my point today.) The mistake here is to confuse the "why" with the "how." We are in need of various explanations. One thing that needs to be explained is why the organism behaves the way it does. Adaptationist explanations may serve to satisfy that explanatory need. But how the organism manages to achieve the behavior is a different explanandum entirely.
Here's the little bit of argument that came to me this morning: An adaptationist explanation might explain how a tiger came to have a sharp claw. That doesn't mean that the sharpness of the claw itself is no longer of interest to a zoologist. The sharpness must be referenced if we are to understand how the tiger satisfies its nutritional requirements. It is an indispensable part of the "how" explanation.
Adaptationist explanations, as "why" explanations, lie "upstream" from "how" explanations. As Aristotle pointed out long ago, there are in fact various types of causal explanation. No one would think that the claw's sharpness was causally irrelevant to the tiger's functioning. But evolutionary psychologists (Dawkins) make the same mistake when they suggest that the intentional properties of psychological traits are causally irrelevant on the grounds that the real cause is genetic replication. Thus to explain that the dog is adapted to love you doesn't constitute any kind of argument that the dog doesn't really love you. (Same as in the infant's case.)

Rule-following and "Rule-following"

Many processes can be modeled mathematically. Hurricanes, gene dispersion, baseball statistics, insect wingbeats, galaxy formation: really, the list is endless. All of these processes can be said to "follow rules." Computers follow rules in this sense. But when we say about various natural processes that they "follow rules," it is important to keep in mind that the phrase is here used figuratively: there is no conscious rule-following going on, the way there is, say, after you have just taught me a card game and I try to play it correctly. We often use this figurative sense of "rule-following" when describing processes in our own bodies. The retina, for example, is an on-board computer of a sort that measures the amplitude of light coming in to the eye and "encodes" this "information" for transmission to the brain. "Encodes" and (importantly) "information" are also figurative terms in this context. The eyeball no more literally (intentionally) encodes things than, say, a tree encodes its age in its tree-rings.
Brain processes are "rule-following" only in this figurative sense. Stomachs digest food, but they don't eat lunch. Persons eat lunch. Brains compute (or, they do whatever it is that they do that is the equivalent of digestion in the stomach: our Cartesian error is in the way of our seeing what exactly that is). Persons think. I can't think without my brain any more than I can eat lunch without my stomach, but that doesn't mean that there's a little person in my brain thinking any more than it does that there's a little person in my stomach eating. And the processes going on in my brain are no better explained by saying that there's a person in there "interpreting" than are my digestive processes by positing a micro-gourmand. Inside my head there's lots of "rule-following" going on, but there is no rule-following. Actual rule-following is done by persons, out in the world. Thus the savant is "rule-following" (computing with his brain), but he is not rule-following (thinking with his "mind').
(Thanks to Kevin Vond for a lively exchange on this topic. See the comments below and go to Kevin's website for more.)

Reconciling Turing and Searle

Two arguments that seem persuasive to me lead to a contradiction. The contradiction is resolved when we appreciate that "mind" is a complex concept, and that we are faced with two metaphysical problems, not one. Getting clear on this clears up a whole lot of confusion in the philosophy of mind.
The two arguments are owed to Alan Turing and to John Searle, respectively. Turing makes the basic operationalist case: confronted with a system, any system, that behaved (reacted to us, interacted with us) in a way that was indistinguishable from a rational person (for example, a computer terminal that could converse rationally and sensibly), we would have no option but to consider that system rational ("minded," if you will). The claim is deep and strong: granting consistently rational behavior, to deny rationality to such a system would be the equivalent to denying that another normally-behaving human was rational; there would be no evidence to support such a denial. More strongly still, the only meaning we can assign to the concept "rational" must be pegged to some observation or another (Wittgenstein's behavioristic point).
Searle's "Chinese Room" argument, on the other hand, appears to demonstrate that the mind cannot be (merely) a formal rule-governed, symbol-manipulating device. The non-Chinese speaker in the Chinese Room follows a set of formal rules ("when a squiggle like this is entered, you output a squoggle like that"), and these rules are such that the Chinese-understanding person inputing Chinese-language questions is receiving appropriate Chinese-language answers as output. But it seems persuasive that neither the homonculus inside the Room nor the Room as a whole has any idea of what is being said: like a computer, the Chinese Room understands nothing whatsoever.
How can the seemingly mutually-contradicting intuitions that are motivated by the two arguments be reconciled? Here's how: Turing is talking about intentional mental attributions: psychological descriptions using terms such as "belief" and "desire." The meaning of intentional psychological descriptions and explanations is necessarily grounded in observables. Intentionality must be understood operationally, and Turing is right that any system that can be successfully understood using intentional predicates is an intentional system: that's just what intentionality is. Searle, meanwhile, is talking about phenomenal mental attributions (consciousness). The meaning of phenomenal terms must be grounded in intersubjective phenomena, just like intentional terms (or any terms in language), but there is something more (Wittgenstein: an inexpressible something more) whereas to be in an intentional "state" is entirely public. Only conscious beings "know" anything at all in Searle's sense. Wittgenstein too is skeptical of the possibility of "zombies." "Just try - in a real case - to doubt someone else's fear or pain," he writes in the Philosophical Investigations Section 303. And now we have sailed out into somewhat deeper water.

A Linguistic Argument Against Relativism

One of Wittgenstein's most famous arguments is known as the "Private Language" argument but it might be more accurate to refer to it as the "Public Language" argument, as the starting point is that language (like playing games) is the kind of thing that happens between people, out in the world. There are neither words nor rules "in the head" (Wittgenstein also doubts that there are any images or anything else to "look at" in the head, but that requires some additional attack. Roughly, I think that the idea here is that it explains nothing to posit any sort of "mental representation"). Language, furthermore, does not generally function on the model of "object-designation," rather there are myriad functions that are performed using language, all of them coordinations between subjects. Thus classical "meaning" semantics is replaced by a kind of functional-role semantics: the "meaning" of the utterance is just the pragmatics of the performance of the utterance. This public account of language, if correct, precludes the possibility of phenomenology. We can talk about "blue," but we cannot, using language, gain any purchase on "blue-for-me," or "blue-to-you." These are literally meaningless constructions, not because we are zombies (my students keep thinking that Wittgenstein is claiming that we are zombies), but because the quality of experience is beyond the reach of language. If "relativism" is the claim that there is no such thing as Truth, Wittgenstein's language argument exposes some philosophical (Wittgenstein would say "grammatical") confusion. On the one hand, he would take the point that there is nothing meaningful in any attempt to talk about "Truth" as something that "exists" independently of some specific, contextual "language-game." So what epistemologists have lately been calling realism (Arthur Fine?)is a misguided project. But by the same token, there is nothing in statements such as "What's true for you is true for you, what's true for me is true for me." Anything that's "true" (any actual use to which we might put the concept of truth) is necessarily intersubjective. I suspect also that the "end of objectivity" rhetoric of Richard Rorty, informed as it is by some serious consideration of Wittgenstein, is a misapplication: commitment to beliefs and principles doesn't evaporate along with classical semantics, any more than consciousness does.

Semantics and Uniqueness

For a while I've been thinking that I'm stuck between the two poles of Plato and Wittgenstein, although on some days I'm better at explaining what that means exactly than on others. Today in Epistemology we chewed over an inchoate idea that floated through my mind yesterday. (Wilbert Munoz pointed out that we were talking about metaphysics more than epistemology, which was true enough, but we got there honestly: we've been thinking about Nagel's attempt in The View From Nowhere to establish some way of talking about subjectivity as something in the world, and I'm pretty sure that Wittgenstein is right (contra Nagel) that this is not possible.)
Anyway, the half-baked ("inchoate" is a fancy-pants way of saying half-baked) idea was this: Wittgenstein argues that the semantics of all language is necessarily grounded in public, intersubjective referents, and that this extends to psychological ("phenomenological") terms (for example in the "beetle-in-a-box" passage). Meanwhile Plato seems committed to the view that any description of a particular is necessarily in terms of properties, and thus descriptions are composed of assignments to categories (I guess Aristotle thinks this too, although they have opposite accounts of primary being). If some particular had a property that was unique to that particular, could we name it? I have the feeling that the answer is going to have to be "no." So, the connection: the Cartesian claims that the taste-of-chocolate-for-me is a real element in the world, one that only I can know about etc. Wittgenstein counters that we can only talk about plain old taste of chocolate. Is the putative (or possible) uniqueness of the taste-for-me what precludes the possibility of meaningful reference to it? And does this reveal an unexpected similarity between Plato and Wittgenstein, inasmuch as both think that reference amounts to a kind of categorization? Just an inchoate note, I have to go make some photocopies for 11:30 class.

Philosophy and Ethics Across the Curriculum

This week we're discussing a bureaucratic issue here at the University of Puerto Rico at Mayaguez. The university is trying to develop "Ethics Across the Curriculum," specifically ethics seminars in the Agriculture, Business, Computer Science, Engineering, and Nursing programs, among other possibilities. The problem is, should my fellow philosophers and I insist that courses in ethics necessarily involve input from philosophers? (And, for example, should such courses be "cross-listed," given two course codes, one in philosophy? As I say, our problems are largely bureaucratic.)
I think that the answer is no. There are non-philosophical elements of my opinion, such as the fact that our little Philosophy Section is "the mouse that roared" so far as the Business School or the College of Engineering are concerned, but there is also a substantial philosophical point so I'm posting about it here.
It's true that in the classical tradition moral instruction, understood as How to Live the Good Life, was considered to be the province of philosophers. But at that time the term "philosophy" was much broader than it is now: there was "natural philosophy" and "moral philosophy," moral philosophy encompassing what today we would call history, political science, and in general the humanities and social sciences, although it is true that we have lost the classical idea that students ought to be studying to be good persons (perhaps this is too collectivist for us).
Today, philosophy is something much more specific. I would define it as the study of metaphysics and epistemology. However, that doesn't mean that ethics is not an area of philosophy. Ethics, like aesthetics, religion, psychology, science, and mathematics, to name some prominent examples, is interesting to philosophers because ethical propositions have a metaphysically and epistemologically ambiguous relationship to "natural" propositions, propositions about, roughly speaking, the physical world (I say "ambiguous," I don't necessarily believe that ethical propositions cannot be naturalized; I don't accept the "naturalistic fallacy" argument, for example).
I'm not, then, a metaphysics jock who "doesn't do" ethics. I'm covering ethical theory in my Intro course right now, as a matter of fact. I'm interested in empiricism and ethics, specifically non-cognitivist theories and the role of logic in ethical reasoning, and the difference in the way rationalist approaches and empiricist approaches fix the extensions of the sets of moral patients and moral agents (Kant thinks they're coextensive, Mill and Singer, say, do not), and I have discussed the naturalistic fallacy in earlier posts as well as the law of effect as a basic empiricist principle. I definitely "do" ethics.
It's just that I don't think that the metaphysical and epistemological investigations of philosophers qualify philosophers in any way as experts on normative ethical codes (specific ideas about what sorts of things are right and wrong), or as social and political critics (analyses of the justice or lack thereof of social and political arrangements). I think that there is a basic conceptual error here: the fact that ethics is philosophically interesting doesn't make it the exclusive domain of philosophers, or necessarily any domain of philosophers. Physics is philosophically interesting too, but if one wants to learn about physics the place to start is Intro Physics.
Where do we start if we want to learn ethics? I think that "ethics" is a highly heterogenous concept. Aristotle says in the Nicomachean Ethics that if you want to learn how to be a good person, find someone who you feel certain is a good person and watch what they do. So for Agricultural Ethics or Business Ethics or whatever it may be, it seems sensible that one finds an instructor with some experience and reputation of ethical conduct in that field. I don't see how the student in another profession is going to be much improved by listening to a professional philosopher explain consequentialism vs. deontology, say, as philosophically interesting as that distinction may be.
One final thought for the blog (not something to belabor in a faculty meeting, in my opinion): philosophy isn't the most important thing in the world. Discussions of cultural and ethnic biases, of sexism and racism, of economic and social justice, are discussions that in my opinion, and speaking as a philosophy professor, are all more important than the rather abstruse topics philosophers choose to chew on. As a society we should be (and we are) spending more time on those issues than we are on philosophy. But that doesn't mean that those are the topics that a responsible philosopher ought to engage with, any more than a good professor of, say, organic chemistry or 17th century Italian opera needs to stop everything and plunge into a political consciousness-raising session.

On Plato's Dualism

Plato's dualism is a dualism of matter and form. For Plato, the distinction between mind and body is one example of the larger distinction between form and body. As matter nears closer to form, it becomes more and more formally organized, the reverse as it recedes from form. Circular objects are good examples: the more perfectly circular particulars are closer to the form of circularity. But then the roundness of my finger, say, is a case of my person being a mix of matter and form. There are many ways that my body is exemplifying form. The fact that I can do logic and mathematics, then, is not the only form/matter distinction that I exemplify. This is the sense in which the mind/body distinction is only one example of a larger distinction, the real metaphysical distinction, matter and form. The significance of this for philosophy of mind, I think, is that there is nothing metaphysically unique about my rational capacity. Dualism, for Plato, is already established by my finger's having the property of circularity, a formal, not physical, property. The further intuition that thinking logically is somehow mental, whereas simply being round is not, is no part of Plato's dualism. So, perhaps, the claim that the "rationality assumption" in intentional psychology has no correlate in physical description is incorrect. Physical descriptions are shot through with references to formal properties, and so intentional psychological descriptions are not metaphysically exceptional in that sense.

Do You Have to be Good to be Guilty?

We're transitioning from free will/determinism to ethical theory in Intro this week. The literature of action theory is old and hoary, so I'm not hopeful of plowing new ground, but it sure is fun. Here's today's discussion (7:30AM, no less): it appears that the notion of responsibility involves us in a paradox.
1) A free action must be the action of an agent: agents are free.
(I take this to be the indubitable compatibalist point of the empiricists. "Free" is an adjective. You've got to be somebody in order to be free, because you've got to exist in order to be a cause; if you're not the cause, then it's not your act.)
2) To be someone, one must have a nature/essence/character/personality.
(We recognize you from one time to the next, not just on the basis of your physical constancy, but on the basis of your psychological and behavioral constancy as well. Otherwise we could not say that you were a person. You must have at least that much stability and continuity. This is why quantum indeterminacy, for example, cannot underwrite freedom of action. Randomness or chaos or absence of causes may be real, but their consequences are not your acts, and it's your acts that are free or not.)
3) But to have a nature appears to be equivalent to being determined.
That is the paradox of responsibility. R. M. Hare captures the paradox nicely in the title of his book Freedom and Reasons: to the extent that I have reasons, we can say that my actions are my own (those that are caused by my reasons). But to the extent that I have reasons, it appears that I am not free. Hobbes doesn't mind this. He thinks that the only coherent definition of freedom is "the ability to pursue my desires." Hume says that "Reason is the slave of the passions." And it is Mill's view that values emerge in a world where there are beings that have experiences that are good and bad, this fact being entirely contingent.
I think that this empiricist compatibalism is right. The problem for Sartre and the existentialists, say, is that freedom vanishes along with the concrete (psychological) self, whereas Plato, Kant and the rationalists lose freedom in the grip of logical necessity. But this still leaves much to be said. How can I do good, if I am a good person by nature? That is, what can be praiseworthy about my action, if it follows from my essential good nature? And how can the bad man (that other man!) be said to do wrong? When we say that the good person is good, isn't that like saying that he's lucky, or good-looking? But that's not how we mean ethical praise, is it?

Kant's Cure and the Disease

This morning I'm thinking about Kant. Usually these days for me, Kant is a big source of a sort of rampant Cartesianism that I see in the classroom and in the popular culture. This is a teacher's perspective. His idea that the mind projects a conceptual structure onto the world (Kant thought that space and time, cause and effect, were more creations of the mind than perceptions of real being) is variously presented as obviously the thesis of Plato and as obviously the thesis of Nietzsche, and I've even encountered people who insisted that Plato and Nietzsche were complete opposites and that they were both Kant. All the facile rhetoric of "I believe what I believe, you believe what you believe" that we swim in seems to smell of Kant (is it the same river that smells of Kant from day to day?). It also appears to me that Kant, in his insistence that a transcendent rationality was what set humans (to be fair, he's careful to always say "any rational beings") apart from the rest of creation, and that ethical thinking is just equivalent to rational thinking applied, is indeed very like Plato. So I often think of Kant (Hume guy that I am) as the representative of the old regime, a synthesis of Plato and Descartes to be undone by the "bottom-up" post-Enlightenment scientists.
So I got to thinking when I saw in a post on Tractatus Blogico-Philosophicus that cited Schopenhauer as writing that Kant "had circumnavigated the world and shown that because it is round, one can not get out of it by horizontal movement." Kant saw himself as saying something new, notoriously comparing his own insight to that of Copernicus. I think that roughly the idea is that the classical tradition sought for an external cause of the intelligibility of the world (The Good, God), whereas Kant had demonstrated that the intelligibility of the world could only be understood as a property of the mind. So the irrationality of faith that is emphasized in Kierkegaard and Nietzsche is present in Kant's formulation that God, like freedom, must be a part of the ineffable noumenal world. But on Kant's view Mind is just as metaphysically separate from matter as Form ever was for Plato. He just took over from Descartes the task of additionally sticking us in our heads. Still it's technically speaking very modern for Kant to argue that a lot of traditional metaphysics just couldn't be done, as things couldn't be known otherwise than as how our minds organize the representations of things. Totally Cartesian.

Two Senses of "Eliminativism"

Any number of theories of mind might be described as "eliminativist," but there are two very different senses of that term depending on the theory on offer. "Operational" theories of mind such as behaviorism and functionalism are eliminativist in the sense that they deny the existence of non-physical, Cartesian minds (or at least the need to refer to such entities in order to do psychology). In general materialist theories are eliminativist in this sense (by definition materialism eliminates the non-physical). More specifically, behaviorism, for example, eliminates internal symbols, or mental representations (that's really what is most significant about behaviorist approaches). If we redefine "Cartesian" to mean representational models of mind, this type of elimination also turns out to be a feature of materialist theories in general. Wittgenstein understood this, and he also extended the point to philosophy of language: there can no more exist semantic properties than there can be intentional properties, both must turn out to be figurative language at best. The other sense of "eliminativism" is the one promoted by Paul Churchland. This is the claim that the traditional categories of intentional states ("beliefs," "desires," etc.) will not survive the maturation of neuroscience. But materialism does not necessarily imply this. A behaviorist sees the traditional categories as categories of behaviors, and the reductive materialist sees them as categories of physical states. The problem of multiple realizability, an essential motivation behind the development of functionalism, is predicated on the ineliminative nature of the categories, in fact. I think that Churchland makes the mistake of assuming that psychological predicates must refer to states that are "in the head" one way or another, while Wittgenstein understands that the key is to see that psychological predicates necessarily refer to public phenomena (and note that the Churchlands disdain Wittgenstein in their disdainful way; they don't grasp him). In fact the eclipse of representational models of mind would not entail the elimination of the traditional intentional categories. I doubt that they are eliminible at all. They pick out basic features of persons. They are not part of a theory. Meanwhile I doubt that there are anything like symbols (or language) in the head, the current vogue for representationalism notwithstanding.

Exopsychology

My four courses have come together this week more than usual. In Intro we're reading Bertrand Russell's version of the argument by analogy for other minds and Ryle's "ghost in the machine" rejoinder, in Epistemology we're reading Thomas Nagel's The View From Nowhere, but at the moment we've detoured to reading Nagel's "What is it Like to Be a Bat" article and Frank Jackson's "What Mary Didn't Know," and that led us on to David Lewis, "Mad Pain and Martian Pain." So the six of us are trying to figure that article out. In Contemporary we're reading Kenny's chapter on philosophy of mind, which covers Bentham vs. Kant, psychoanalysis, and the Tractatus. And in Philosophy of Psychology we're moving out into Braddon-Mitchell and Jackson's Philosophy of Mind and Cognition, finishing Part One explaining "commonsense functionalism," the view they espouse.
So I was struck by the article in today's NYT "Smaller Version of the Solar System Is Discovered," which turns out to be an excellent illustration of functionalism's advantage over reductive materialism, in addition to being philosophically significant in itself. In our age we're used to physics and biology being philosophically significant sciences, but for much of the history of the modern world astronomy has been seen as posing as great a threat to established ideas as, say, evolutionary biology or big bang theory is seen today. The culture that existed before Copernicus, Kepler and Galileo displaced humans from the center of the universe is not the same culture afterwards. This process continued during the 20th century, when Hubble showed that our Milky Way Galaxy is only one of a great many galaxies, and recent observations with the Hubble Space Telescope have caused the estimation of the number of galaxies to be greatly increased. Meanwhile we have seen through spectroscopy, for example, that the natural processes that we observe on Earth, as well as other constants such as the distribution of elements, is apparently much the same in the rest of the universe as it is nearby. The right combination of common ingredients, between a heat source and a heat sink, will start forming the "primal soup," protein chains out of which organic life is built up. The universe is full of life to a mathematical certainty; it's not rational not to believe it. Since 1995, over 250 exoplanets (planets in orbit around stars other than our own) have been discovered, using the wobble effect (the gravitational pull of a massive satellite observed as a tidal pulse on the star surface). Now a new technique called microlensing exploits the refraction caused by one object's gravity bending the light from a more distant object. Today's story informs us, among other things, that the number of nearby stars with planets seems greater than had generally been imagined, and that systems with gaps where temperate, Earth-sized planets might be are being observed.
One type of functionalism is a kind of non-reductive materialism: every token of a mind is a token of a physical thing as well, but mental types supervene on physical types (multiple physical types can realize the same mental type). So psychology doesn't just analyze down into the physical understanding of human nervous systems. To see the point think of the exobiologists: their job is to think about what exoorganisms might be like, what they must be like, what they can't be like, and so forth. The magic of it, as someone else said somewhere, will not be just in the differences or just in the similarities. The magic will be the blend of similarity and difference. Exobiology suggests exopsychology. Functionalism aspires to be a kind of exopsychology: what must be true of a thing in order for it to come under psychological description? What defines the set of "persons"?

W. K. Essler on Buddhism

This is the second week of a two-week "mini-course" offered here at UPR/Mayaguez by Wilhelm K. Essler, professor of philosophy at the University Mamat in Germany, and author of Die Philosophie des Buddhismus (2006). Dr. Essler is an authority on Kant and a scholar of Ancient Greek philosophy, as well as someone with a lively interest in words and in the ancient languages of Sanskrit, Pali, and others important to Vedic and Buddhist philosophy. In our class he is explicating the Four Noble Truths and the Eightfold Path, having spent some time on earlier Vedic influences. His presentations are quite interesting and useful.
I want to raise some questions about taking a Kantian-eye's view of Buddhist teachings. I'm not actually attributing any of these arguments or positions to Dr. Essler, because I am frankly not that confident that I understand his ultimate position on these things, but I have my own thoughts on Kant and Buddhism that I am writing out here so that, among other reasons, I can show them to Dr. Essler and see what he says.
The good idea in Buddhist philosophy of mind that I see, and that Dr. Essler is also focused on, is that the self, as constitutive of the world, cannot be included in the ontology of that world. It makes a big difference, however, if this is interpreted to mean that consciousness is the ground of the world (to use Kantian language, a necessary precondition for the possibility of the world), or it is interpreted to mean that consciousness is identical to the world (Hume: phenomenal experience=mind).
The Kantian interpretation holds that the technique of the transcendental deduction yields a proof of the existence of the mind as something apart from the experienced world.The problem that I have with the Kantian interpretation, which appears to infect the entire German Idealist tradition of the 19th century, including Schopenhauer, is that the Kantian interpretation underwrites a further metaphysical discussion of the self, this time as part of a noumenal aspect of reality. Thus Schopenhauer attributes to the Will a kind of Parmenidean unity, among other fantastic properties.
Meanwhile, the interpretation that is suggested by Buddhist language (Dogen: "The blade that cuts, but does not cut itself") and, I think, by Wittgenstein in the "solipsism" passages in the Tractatus and upheld later in the Investigations is a kind of eliminativist interpretation: that phenomenal properties do not exist. There are no such properties, and there is nothing like traditional notions of "mind" or "consciousness." The discussion of dependent arising in the Four Noble Truths is the genealogy of bad karma that is just identical with the "self," which is something that must be addressed through Buddhist practice. (My own interest in this point, by the way, developed not so much from my interest in meditation as from my interest in the problem of phenomenal properties as a block to naturalism about the metaphysics of the mind/body problem, notably modern versions like Frank Jackson's "Mary" argument and discussions of phenomenology as a problem for behaviorism and functionalism, such as Chalmers' "zombie" discussion. My current view on these matters, inspired by Wittgenstein and Buddhism, is that the problem of phenomenology is a pseudoproblem, as phenomenal properties do not exist.)
Meanwhile, just a comment on Essler's dismissal of meditation. Whether we take what I am calling a "Kantian" or an "eliminativist" interpretation of the Buddha Dharma, either way meditation is a key technique in the Buddhist tradition that roughly tracks on to what we call "phenomenology." As with many older traditions, they have plenty to offer to people with similar interests. For example I would recommend "mindfulness" meditation to anyone with an interest of the theory of self developed in Being and Nothingness. Essler wants to approach Buddhist metaphysics and epistemology in a spirit of philosophical excavation and reconstruction, but his dismissal of meditation is a shortcoming.
(I recommend the excellent comments made below by the notorious Silencio Bouche.)

Early and Late Wittgenstien

The Wittgenstein of the Tractatus, with his "atomic", "picture" theory, was still seeing the issue as one of the way language and mind represent the world. He had the idea that what pictures represented was not so much individual things as relations between individual things, or what he called "facts." Language captured (or ought to capture) logical relations. His fascination with the relationship between logic and pictures is very High Modern, like one of those Cubist paintings by Braque or Picasso.
In the later Philosophical Investigations Wittgenstein moves away from representational ideas altogether. The fundamental insight was that an authentically naturalized account of mind and language would have to have done with intentional and semantic properties altogether. This is a kind of behaviorist/functionalist reading of Wittgenstein: there are no such things as symbols. There is nothing "under the surface" of language (no meaning) and thought (no "inner space").
It is important to see the continuity between the earlier and the later work. The idea that consciousness and qualitative experience (and "good and bad," for example) were not possible objects of representation is common to both books, and an exploration of the limits of language is an organizing principle of both. Sometimes people who like the Tractatus dismiss the P.I. and vice versa, but that is a mistake.

Hume's Response to Skepticism

Most traditional interpreters of Hume have read his language of "impressions" as Cartesian/Lockean, in the sense that he is wedded to a representational view of mind such that skeptical doubt is an inevitable (albeit perhaps trivial) problem. Thus the empiricist is a kind of cheerful skeptic, suggesting (as Hume does) that rationalist approaches overstep their bounds in the face of inscrutable nature. I've been wondering if Hume wasn't perhaps closer to Wittgenstein, with his idea that skepticism is a kind of pseudoproblem, than he was to early 20th century "analytic" philosophers, like Russell and the "phenomenalists" of early 20th century philosophy of science. So I was pleased to see that one of the selections in my Intro anthology was "Of scepticism with regard to the senses," Book 1 Part 4 Section 2 of the Treatise. Three paragraphs in we find "For as to the notion of external existence, when taken for something specifically different from our perceptions, we have already shown its absurdity" and we get a footnote directing us to "Of the idea of existence, and of external existence," Book 1, Part 2, Section 6.
Hume writes, "The idea of existence, then, is the very same with the idea of what we conceive to be existent. To reflect on anything simply, and to reflect on it as existent, are nothing different from each other. That idea, when conjoined with the idea of any object, makes no addition to it. Whatever we conceive, we conceive to be existent. Any idea we please to form is the idea of being; and the idea of being is any idea we please to form."
The Cartesian reading of this sort of thing is that we cannot get around our "ideas" or indeed past our "impressions" in order to know the external world directly. For all we know the external world might not exist, but there's simply no sense playing philosophical parlor games. Beyond experience lies the unknown. (I noticed reading Bryan McGee's Confessions that he was particularly enamored of this sort of idea, which he attributed to Kant.) But it looks to me that there is a much more powerful argument here, one that does aim to defeat Cartesian skepticism. On this more Berkeleyan reading the external world just is experience just is the external world. There cannot be any "abstract idea" (Hume thinks that the problem is that these are fishy abstract ideas) of an existing thing apart from our actual experience. So skepticism is a pseudoproblem motivated by a misconception of the meaning of "being." Experience is the ground of conception, so there are not any genuine concepts that extend beyond experience. This I take to be broadly equivalent to Wittgenstein's diagnosis. It is not a mere throwing up of the hands of an empiricist: I think that Hume positively rejects the Cartesian possibility as a demonstrable error. One can not be said either to "know" or to "not know" about the existence of the external world. Wittgenstein is making the same argument with his appropriation of the word "solipsism" at the end of the Tractatus.

Is Hume Moore or Wittgenstein?

G. E. Moore tried his hand (irresistible pun) at overcoming the Cartesian skeptical problem, that if one grants that we only experience our own mental representation of the world, knowledge (about the actual world) is impossible. In "A Defense of Common Sense" (1925) and "Proof of an External World" (1939) he proposed that we can recognize paradigm cases of knowledge (famously including "That I have a hand"), and that establishing the truth of such knowledge claims establishes the falsity of the skeptic's claim that any knowledge about the external world may be false. I find Moore's style of argument, both here and in his exposition of the "naturalistic fallacy" in Principia Ethica, to be awfully fast, but one can see how Moore felt that he was carrying on David Hume's legacy with this kind of Modernist, anti-philosophical philosophy. If there is a conflict, Hume teaches us, between what ordinary people take to be simply given and what the rationalist takes to be logically necessary, then so much the worse for logic. I'm always careful to suggest to my students that the way to think about the possible significance of Cartesian skepticism is that it shows that rationalist philosophy has problems, rather than locating the problem in ordinary belief (if the student calls me at 2AM worried that the world is not real, my counsel is that he drink some water, go for a walk, and lay off those funny cigarettes).
However, Wittgenstein zeroed in on Moore's work, which Wittgenstein felt failed to cure the philosophical disease. He wrote a short manuscript late in his life that was finally published in 1969 titled On Certainty. On Wittgenstein's view, the problem was that the skeptic used the verb "to know" in a context in which it could have no meaning. It means something to say that "He knows that Aguadilla is north of here," or "He doesn't know if there is any spaghetti sauce left," because these statements are predictive of his actions and prescriptive of ours (this is the behaviorist side of Wittgenstein); Wittgenstein develops a type of functional-role semantics. Put another way, we are genuinely informed by ordinary attributions of knowledge because it could have been different: to say "he knows" makes sense because he might not have known. The external world as such, then, is not a legitimate object of knowledge. It is part of the context in which "knowledge" is possible. Thus, we neither know nor do not know anything about the existence of the external world; the verb "to know" can gain no purchase here. Moore's strategy for defeating Cartesian skepticism fails because Moore continues to commit the same "grammatical" (as Wittgenstein calls it) error as the skeptic. Moore no more "knows" that he has a hand than the skeptic "doubts" it: both are failing to make meaningful statements.
So a question of Hume interpretation: is Hume Moore or Wittgenstein? This is significant because standard Hume interpretation holds that he was a kind of happy skeptic. The standard line is that, since he held that the boundaries of sensory experience are the boundaries of knowledge, he fully embraced the Cartesian condition, that we can never know anything other than the "impressions" that are mental, not physical things. But I think that this phenomenalist reading of Hume owes a great deal to the early analytic philosophers such as Moore and notably Russell. Hume says that knowledge has limits, and that the philosopher must be comfortable with the fact that understanding can only be extended so far and no farther, on penalty of sophistry. This strikes me as much closer to the Wittgensteinian view that "the limits of my language are the limits of my world" than the traditional interpretation of Hume, that skepticism cannot be refuted and w