Peter Unger's 3 quarks daily interview about his forthcoming book, "Empty Ideas: A Critique of Analytic Philosophy", has generated an immense amount of interest around the philosophy blogosphere--and for a number of reasons (if you don't know the reasons...read the interview). ;) Anyway, I don't want to get hung up on what Unger says. I want to think more about the general thrust of his forthcoming critique of analytic philosophy.
Now, obviously, I haven't read Unger's book. It's pretty clear from the interview and book description, however, what Unger means to argue. He contends that analytic philosophy has almost entirely been dominated by "concretely empty ideas", where such an idea is one that does not make a difference to how things are with concrete reality (this is his implied definition from the book overview here).
There is, I think, a simpler way to put this: analytic philosophy has, by and large, not tended to make any predictive empirical claims about the world around us. So, for instance, whether we are "nihilists" about physical objects (viz. "there are no tables, only particles-arranged-table-wise") or compositionalists (viz. "there are tables, and they are composed by particles!"), neither view makes empirical predictions about the world (viz. there is no empirical experiment we could run to verify/falsify either view). I think this is right. Even brain scans, I believe, would simply reveal that our concept of "tables" and "composition" are indeterminate between these two conceptual schemes.
But now if this is all Unger is saying--if all he is saying is that analytic philosophy does not make empirical predictions--then, I imagine some philosophers will say (as some have implied here), what's so bad about that? Did we ever think philosophy made empirical predictions to begin with? Isn't that science's domain, not philosophy's? Indeed, some over at the Leiter thread have said, essentially, "Look, I'm happy if philosophy doesn't deal with what Unger calls 'concretely substantial ideas', ones that have concrete, empirical implications. For I still think philosophy that doesn't make concrete contributions to science is valuable!" Further, I've seen many on social media say, "Unger's view presupposes a perversely scientistic, reductionistic theory of reality."
I believe this kind of response to Unger is wrong--and indeed, that it is no good as a defense of analytic philosophy. Allow me to explain why.
Richard Brown and Pete Mandik posted a fun discussion of the relationship between philosophy and science, hilariously entitled "The Unger Games", over at SpaceTimeMind. One of the things Brown and Mandik touch upon is why philosophers aren't taken very seriously by scientists or the broader public--and they do so by analogy with the history of psychology. Prior to the "scientization" of psychology, psychology was a joke. There was Freud speculating on penis-envy, Maslow speculating on hierarchies of needs, Humanists speculating on "self-realization", and so on. It was, we now know, mostly a bunch of largely baseless speculation. Science, gods-bless-it, gave psychology respectability by...you know, actually making determinate predictions about the concrete world around us.
Now, before I go any further, let me be clear about one thing. I do not endorse any kind of simple, reductionist physicalism. As I argued in "A New Theory of Free Will", I think--along with people like Chalmers, etc.--that physical science (as we currently understand it) cannot be the full and correct story of the world. Physics, in brief, deals only with quantities and relations between things (electrons do such-and-such), and there are some things--consciousness, the passage of time, etc.--that, as qualities, cannot be neatly incorporated into a scientific worldview. I not only think that physicalism (as traditionally understood) is probably false; I think is has to be false in order to explain quantum mechanics properly. Indeed, although I only briefly mention this in my paper, I actually think it is a necessary truth that all worlds are dualistic--that to be a world at all is to comprised by "software" and "hardware", which are two fundamentally different types of things.
But I digress. I just wanted to be clear that I do not subscribe to scientism (viz. "physics is all there is--leave it to the scientists!"). I think philosophy has a real role to play in human inquiry, viz. the parts of reality that science cannot get at.
Anyway, what I agree with Unger on--and what I want to make the case for--is this: just as psychology was "mere speculation" prior to actually making predictions, the same is true of philosophy. As I argued in "Misled by language?", I think that philosophy that does not make any predictions at all is mere concept manipulation--manipulation of fundamentally indeterminate concepts that, by virtue of conceptual indeterminacy/vagueness, cannot in principle provide answers to the conceptual questions analytic philosophers ask. Allow me to explain why.
I believe analytic philosophy tacitly presupposes a flat-footed Williamsonian epistemicism about vagueness that is empirically false. For those of you who don't know Williamson's theory, Williamson thinks there is some unknown fact of the matter about precisely how many hairs makes a person bald (or balding), and about precisely how many grains of sand comprise a heap (viz. N grains is not a heap, N+1 is a heap). Now, almost no one who works on vagueness (besides Williamson) endorses this crazy view--and for good reason: it is almost certainly empirically false. There is nothing in the world that could possibly make Williamsonian epistemicism about vagueness true. Our brains don't code a specific number of hairs for "bald", or a specific number of grains for a "heap", or a precise concept of "material constitution", etc.--nor do our behaviors entail sharp-boundaries.
So, flat-footed epistemicism about vagueness is false. But, I believe, one of the most central practices of analytic philosophy--conceptual analysis, thought-experiments to "clarify" such-and-such--presupposes that epistemicism is true. People who debate whether tables are "composed" of their particles, or whether there are no tables (just particles arranged "table-wise") are assuming--just like the epistemicist does about baldness (N hairs is bald, N+1 is not)--that there is some answer..and that we just might find it if we just look (and argue) carefully, clearly, and rigorously enough. Indeed, just about all conceptual questions in analytic philosophy can be seen to trade on vagueness. "What exactly is baldness? How many hairs are bald/not bald?", is the same sort of question as, "What, exactly, are tables? Are they composed by their particles? Or, are particles just arranged table-wise?", or, "Does free will require actions to be reason-responsive, or not?" These types of "deep" philosophical questions are, I think, precisely what Wittgenstein thought: us being bewitched by vague language. Our language is irreducibly vague. We "want" answers to what exactly a table is, or what exactly composition is, etc., but there is no determinate answer...any more than there is a determinate answer as to how many hairs make a person bald or heap of sand a heap.
So, I say (or at least worry), one of the central practices of analytic philosophy--conceptual analysis--is predicated on a false conception of vagueness. We are seeking determinate answers where, conceptually, there are none. Hence, interminable philosophical debates--debates that never resolve themselves because there is nothing in our concepts that can determinately resolve the issue in question one way (e.g.tables are constituted by particles) or the other (e.g. there are only particles arranged table-wise).
Another way to put this is as follows: in the absence of determinate predictions, philosophy is little more than an exercise in battling argumentatively over how to interpret vague concepts for which there is no determinately correct interpretation (i.e. no truth at all). But now if this is right, then Unger is right. In the absence of predictions, philosophy is not about any determinate truths at all--for it is only concrete predictions that give determinacy to our concepts, latching them onto determinate phenomena in the world (electrons are determinate, so are protons, so are neurons, etc.; that's why there are determinate answers in science).
Return now to psychology. Prior to its scientific turn--prior to psychologists' insistence on making verifiable predictions--there were a vast array of entrenched "camps": Psychoanalysts, Behaviorists, Humanists, etc., all defending their own views of psychology by way of "intuitions", "impressions", and "arguments." It is really striking how similar the situation was to philosophy today. It is only by tethering itself to the natural world that psychology began to make demonstrable progress.
The same insistence on tethering theory to predictions, in fact, spurred the greatest scientific innovations of all time: Einstein's theories of relativity and quantum mechanics. Prior to Einstein, everyone had assumed--yep, you guessed it, philosophically--that space and time had to be absolute (the background against which all things in reality play out). Einstein essentially said, "You know what? What if we actually take seriously the phenomena, and follow them where they lead, come what may?" When he followed the phenomena, he found that the constancy of the speed of light in every reference-frame entails the relativity of space and time. Etc.
Indeed, philosophical speculations on the basis of concepts alone do not have a very good record. Aristotelians believed everything in the heavens must move in circles, since circles are "perfect"...yet we discovered through empirical inquiry that they don't. Phlogiston theorists speculated that fire and heat must be caused by the a substance, "phlogiston"...except we discovered through empirical inquiry that there is no such thing.
I am increasingly coming to believe that philosophy must follow suit. Analytic philosophy deals with concepts...but concepts are indeterminate, and determinate only insofar as they make predictions. "Continental philosophy" deals with...well, consult your favorite definition (I have no horse in this race). I'm not sure we should be doing analytic or continental philosophy anymore--at least not as traditionally conceived. The above reflections suggest that we should be doing something very specific: Natural Philosophy, engaging with scientists, but also with those things (e.g. consciousness, time's passage, normativity) that science cannot get at directly completely, but which can and do entail empirical predictions. We should be philosopher-scientists, and leave a priori speculation to religious sages.
One final point: in arguing for Natural Philosophy--in insisting the philosophy needs to make verifiable predictions to be fruitful--I am not assuming any form of "verificationism" about meaning, etc. For my claim has not been that conceptual debates in philosophy are meaningless. I am happy to admit (contrary to verificationism) that they are meaningful. My claim, rather, is that without making definite predictions, conceptual debates have no determinate answers. Predictions, and the world those predictions are about, lend determinacy to questions. Without them, there isn't any.
But, who knows?...maybe I'm wrong about all this. It wouldn't be the first time. I'm happy to listen! :)