The Crazyist Metaphysics of Mind

 

Eric Schwitzgebel

Department of Philosophy

University of California

Riverside, CA  92521

 

eschwitz at domain: ucr.edu

 

November 7, 2011

 

The Crazyist Metaphysics of Mind

 

 

Abstract:

Crazyism about X is the view that something it would be crazy to believe must be among the core truths about X.  In this essay, I argue that crazyism is true of the metaphysics of mind.  A position is “crazy” in the intended sense if it is contrary to common sense and we are not epistemically compelled to believe it.  Views that are crazy in the relevant sense include that there is no mind-independent material world, that the United States has a stream of conscious experience distinct from the experiences of the individuals composing it, that chimps or the intelligent-seeming aliens of science fiction fantasy entirely lack conscious experience, that mental events are casually inefficacious.  This is by no means a complete list.  Well developed metaphysical theories will inevitably violate common sense, I argue, because common sense is incoherent in matters of metaphysics.  No coherent and detailed view could respect it all.  With common sense thus impaired as a ground of choice, we lack the means to justifiably select among several very different metaphysical options concerning mind and body.  Something bizarre must be true about the mind, but which bizarre propositions are the true ones, we are in no good position to know.

 

 

The Crazyist Metaphysics of Mind

 

Mysterians about the mind – Colin McGinn (1989, 2004), Noam Chomsky (2009) – say that we will probably never know how conscious experience arises from the brain.  But here’s one thing we do generally know, according to them: Whatever the process involved, it’s “natural”.  No hand of God, no immaterial souls required.  But I wonder, if we know as little as they say, why rule out deities and immaterial souls?  If the soul seems a strange and unnatural thing, alien to our science, well, our science is an impoverished tool for penetrating the mysteries of the universe, they say.  A turtle might find strange and unnatural a container ship and might find almost ethereal a schedule of amortization.  If we are but somewhat upgraded turtles, our sense of bizarreness, incomprehensibility, unnaturalness, is no rigorous index of reality.

In this essay I propose a more deeply skeptical mysterianism about the mind than that of McGinn and Chomsky.  On my view, it is probably the case that something it would be crazy to believe – something bizarre and undeserving of credence – is among the core metaphysical truths about the mind.  And immaterial souls aren’t ruled out.

 

i.

 

Bizarre views are a hazard of metaphysics.  The metaphysician starts, seemingly, with some highly plausible initial commitments or commonsense intuitions – that there is a prime number between 2 and 5, that I could have had eggs for breakfast, that squeezing the clay statue would destroy the statue but not the lump of clay – thinks long and hard about what, exactly, they imply, and then ends up positing a realm of abstract Platonic entities, or the real existence of an infinite number of possible worlds, or a huge population of spatiotemporally coincident things on her mantelpiece.[1]  I believe that there is not a single broad-ranging exploration of the fundamental issues of metaphysics that does not, by the end, entangle its author in seeming absurdities (sometimes advertised as “surprising conclusions”).  Rejection of these absurdities then becomes the commonsense starting point of a new round of metaphysics, by other philosophers, which in turn generates a complementary bestiary of metaphysical strangeness.  Thus are philosophers happily employed.

I see three possible explanations of why philosophical metaphysics is never thoroughly commonsensical:

First explanation.  A thoroughly commonsensical metaphysics wouldn’t sell.  It would be too boring, perhaps.  Maybe a famous philosopher can’t say only obvious things.  Or maybe it would lack a kind of elegant serviceability or theoretical panache.  Or maybe it would conflict too sharply with what we know from science.  The problem with this explanation is that there should be at least a small market for a thoroughly commonsensical philosophy, even if that philosophy is gauche, staid, and scientifically stale.  Common sense might not be quite as fun as Nietzsche’s eternal recurrence (1883-1888/1967) or Leibniz’s windowless monads (1714/1989); it might not be as elegantly useful as Lewis’s possible worlds (1986) or as scientifically current as __________ [insert ever-changing example]; but a commonsensical metaphysics ought to be attractive to at least a certain portion of philosophers.  At least it ought to command attention as a foil.  It oughtn’t be so downmarket as to be entirely invisible.

Second explanation.  Metaphysics is very difficult.  A thoroughly commonsensical metaphysics is out there to be discovered; we simply haven’t found it yet.  If all goes well, someday someone will piece it all together, top to bottom, with no serious violence to common sense anywhere in the system.  I fear this is wishful thinking against the evidence.  In the next several sections I will discuss the case of the metaphysics of mind in particular.

Third explanation.  Common sense is incoherent in matters of metaphysics.  Contradictions thus inevitably flow from it, and no coherent metaphysical system can respect it all.  Although ordinary common sense serves us fairly well in practical maneuvers through the social and physical world, common sense has proven an unreliable guide in cosmology and probability theory and microphysics and neuroscience and macroeconomics and evolutionary biology and structural engineering and medicine and topology.  If metaphysics more closely resembles items in the second class than in the first, as it seems to, we might excusably doubt the dependability of common sense as a guide to metaphysics.[2]  Undependability doesn’t imply incoherence, of course.  But it seems a natural next step in this case, and it would tidily explain the historical fact at hand.

On the first explanation, we could easily enough invent a thoroughly commonsensical metaphysical system if we wanted one, but we don’t want one.  On the second explanation, we do want one, or enough of us do, but we haven’t yet managed to pull it off.  On the third explanation, we can’t have one.  I hope you’ll agree with me that the third has at least some prima facie merit.  In sections iii-viii I will further explore the role of common sense in the metaphysics of mind.

Common sense might be culturally variable.  So whose common sense do I take to be at issue in this argument?  I suspect it doesn’t matter.  All metaphysical systems in the philosophical canon, I’m inclined to think, conflict both with the common sense of their milieu and with current Western common sense.  Much of the human worldview is stable over time, especially in Western societies since the early modern period.  Eternal recurrence, windowless monads, and the real existence of an infinitude of possible worlds were never part of any society’s common sense.

Some readers will disagree about the existence of the phenomenon I aim to explain; they will think that there is a thoroughly commonsensical metaphysics on the market.  To some extent, I’m simply taking as a premise that there is none, and I’m inviting you to agree based on your own reading of historical and contemporary metaphysics.  Maybe the premise will appeal better, though, if I highlight its intended scope.  It concerns only broad-ranging explorations of fundamental metaphysical issues, especially the issues where seeming absurdities congregate: mind and body, causation, identity, the catalogue of entities that really exist.  Some skating treatments and some deep treatments of narrow issues might dodge the charge.

Who might count as a thoroughly commonsensical metaphysician?  Aristotle, I’ve sometimes heard.  Or Scottish “common sense” philosopher Thomas Reid.  Or G.E. Moore, famous for his “Defence of Common Sense” (1925).  Or “ordinary language” philosopher P.F. Strawson.  But Aristotle didn’t envision himself as developing a commonsensical view: In the introduction to the Metaphysics Aristotle says that the conclusions of sophisticated inquiries, such as his own, will often seem “wonderful” to the untutored and contrary to their initial opinions (4th c. BCE/1928, 983a; θαυμαστόν: wonderful in the sense of tending to cause wonder, or amazing); and Aristotle generally conceives his project as in part to distinguish the true from the false in common opinion.  Moore, though fierce in wielding common sense against his foes, seems unable to preserve all commonsense commitments when he develops his positive views in detail, for example in his waffling about “sense data” (1953, 1957).  Strawson struggles similarly, especially in his 1985 book, where he can find no satisfactory commonsense account of mental causation.  Reid I will discuss briefly in section vi.

The argument of this section is an empirical explanatory or “abductive” argument.  The empirical fact to be explained is that all existing metaphysical systems are bizarre in some of their major features.  An attractive possible explanation of this fact, I submit, is that common sense is incoherent on matters metaphysical, so that no self-consistent and detailed metaphysical system can satisfy all commonsense constraints.

 

ii.

 

Let’s call a position bizarre if it’s contrary to common sense.  And let’s say that a position is contrary to common sense just in case a majority of people without specialized training on the issue confidently, but perhaps implicitly, believe it to be false.  Claims about common sense are empirically testable, but not always straightforwardly so.  It might, for example, sometimes be difficult to clarify the target claim – e.g., that there is a “Platonic realm” – without either mangling the target view or altering the respondent’s attitude toward it; and what is implicitly believed may be only tenuously connected to explicit questionnaire responses.  The best first pass measure of commonsensicality might be specialists’ own impressions about the degree of conflict between positions in their field and non-specialists’ attitudes, as remembered from their training and reinforced in their teaching, with contentious cases to be referred for more systematic empirical study.

To call a position bizarre is not necessarily to repudiate it.  General relativity is bizarre.  Various bizarre things are true about the infinite.  It’s bizarre yet true that a black and white disk will look colored if spun at the right speed.  Common sense errs, and we can be justified in thinking so.  However, we are not ordinarily justified in accepting bizarre views without compelling evidence.  In the matters it traverses, common sense serves as an epistemic starting point that we reject only with sufficient warrant.  To accept a bizarre view on thin grounds – for example, to think that the world was probably created five minutes ago, or that you are constantly cycling through immaterial souls, or that the universe was sneezed out by the Great Green Arkleseizure (assuming you have no special warrant for these views) – seems crazy.  I stipulate, then, the following technical definition of a crazy position: A position is crazy if it is bizarre and we are not epistemically compelled to believe it.

One needn’t, of course, be clinically insane to accept crazy views, and not all crazy views are as crazy as the three just listed.  Many philosophers and some scientists embrace positions contrary to common sense and for which the evidence is less than compelling.  In fact, to convert a position from crazy to merely bizarre might be the highest form of academic success.  Copernicus, Darwin, and Einstein all managed the conversion – and in the case at least of Copernicus common sense eventually relented.  Intellectual risk-takers nurture the crazy and see what marvels bloom.  The culture of contemporary Anglophone academia, perhaps especially philosophy, overproduces craziness like a plant produces seeds.

Crazyism about a topic, in the sense intended in this essay, is the view that something crazy must be among the core truths about that topic.  Crazyism can be justified when we have good reason to believe that one among several bizarre views must be true but where the balance of evidence leaves no individual view decisively supported over all the others.  We might find ourselves rationally compelled to believe that either T1, T2, T3, or T4 must be true, where each of the T’s is crazy.

Crazyism might be justified in interpreting quantum theory.  The “many worlds” and “many minds” interpretations, for example, sharply conflict, it seems likely, with what most people would judge to be common sense.[3]  And it also seems that the balance of evidence does not compellingly favor either of these views over all competitors.  Thus, the views are crazy in the sense defined.  If the same holds for all viable interpretations of quantum theory, then crazyism appears justified in that domain.[4]

I believe that any well developed materialist metaphysics will be crazy, in the intended sense of the term.  So also, I believe, will any well developed dualist metaphysics.  So also, I believe, is idealism (well developed or not).  And so also are positions that reject all three of these views or aim to reconcile or compromise among them.  But some metaphysical theory of this sort must be true – that is, either some form of materialism, dualism, or idealism must be true or some sort of rejection or compromise approach must be true.  If so, crazyism is warranted in the metaphysics of mind.

 

iii.

 

Materialism has enjoyed such a good vogue in Anglophone philosophy recently that it might not seem to be crazy.  And, indeed, it is not part of my thesis that materialism is crazy.  Rather, my thesis is that any well developed materialist metaphysics will be crazy.  Maybe materialism per se is sufficiently vague and noncommittal as to provide no shock to common sense.  However, I do think that working out the details of a materialist view will inevitably force choices among major violations of common sense, and no one conjunction of violations will merit belief over all rivals.  I offer this assertion as an empirical conjecture about the epistemic status of current theories and theories likely to arise in the near to medium-term future.

The materialist (or “physicalist”) position is difficult to characterize precisely.[5]  This is perhaps a problem for the view – though if so, I’m inclined to think that the problem is just a manifestation of a more general problem I will discuss in section xii.  As a working approximation, let’s characterize materialism as the view that everything in the universe is composed of, or reducible to, or most fundamentally, material stuff, where “material stuff”  means things like elements of the periodic table and the various particles or waves or fields that interact with or combine to form such elements, whatever those particles, waves, or fields might be, as long as they are not themselves intrinsically mental.  The two historically most important competitor positions are idealism and substance dualism, both of which assert the existence of an immaterial soul.

It’s a striking sociological fact about materialism that, after a long history as a minority position, rather suddenly in the 1950s and 1960s a young generation of Anglophone philosophers of mind adopted it as orthodoxy – Hilary Putnam, Jerry Fodor, Daniel Dennett, David Lewis, J.J.C. Smart, Fred Dretske, Donald Davidson, John Searle[6], David Armstrong, Sydney Shoemaker, and many others.  Maybe this sudden generational shift reflected progress, like the progress of science.  It’s also possible that it was the broad swing of a pendulum.  We don’t yet have, I suspect, the historical distance to know.

 

iv.

 

Materialism per se might be contrary to common sense.

Materialism is almost certainly a minority view in our current culture and historically across human cultures.  People have a widespread, and maybe deep, tendency to believe that they are more than just material stuff.  I doubt most readers need convincing of this sociological fact, but for completeness see this note.[7]  Not all unpopular views violate common sense, however.  Even if materialism per se, abstractly put, is bizarre, I doubt that it’s robustly, thumpingly bizarre.  I don’t stake my argument on its bizarreness.  Unstable, tepid bizarreness is not what crazyism is about.

Certain apparent consequences of materialism – of materialism per se, prior to tough choices – might be robustly bizarre.  This would explain anti-materialist philosophers’ fondness of these consequences as an argumentative lever.  Consider Leibniz’s mill:

Moreover, we must confess that the perception, and what depends on it, is inexplicable in terms of mechanical reasons, that is, through shapes and motions.  If we imagine that there is a machine whose structure makes it think, sense, and have perceptions, we could conceive it enlarged, keeping the same proportions, so that we could enter into it, as one enters into a mill.  Assuming that, when inspecting its interior, we will only find parts that push one another, and we will never find anything to explain a perception (1714/1989, p. 215 [§ 17], emphasis in original).

When the view is so vividly displayed, something in most people, I think, resists the materialist’s reduction of experience to bumping matter.  If you see nothing bizarre in Leibniz’s mill, maybe science and philosophy have stolen a bit of your common sense (possibly a good thing).  Other thought experiments work similarly.  Consider “zombies”: It seems we can conceive of entities physically and behaviorally identical to us but entirely lacking conscious experience or “phenomenology”.[8]  Conceivability may or may not imply possibility; the thought experiment has power regardless.  It draws the mind to think that materialism leaves something out.  Consider also Frank Jackson’s (1986) “Mary”, the super-scientist confined to a black and white room, who can seemingly learn all the physical facts about the world, including about the physics and physiology of color perception, yet remain ignorant of some experiential facts, such as what it’s like to see red.  Such thought experiments seem to tap into a folk psychological “explanatory gap” between physical properties or events and the colorful phenomenology of conscious experience; people seem to want to reach for something immaterial to bridge the two.[9]  Maybe, then, it’s part of common sense to suppose that any materialist metaphysics will be incomplete.

v.

 

Regarding materialism per se, I think it’s unclear exactly where the boundaries of common sense lie.  However, I believe that any well developed materialist metaphysics of mind – that is, any plausible materialist metaphysics with specific commitments about the necessary and sufficient conditions for possessing mental states – will inevitably astound common sense.  If it seems otherwise in reading Putnam or Lewis or Smart, that’s because materialist philosophers are often vague on the issues from which bizarreness springs.

If materialism per se conflicts with majority belief and presents a seeming explanatory gap, all the more so, it seems likely, will specific materialist accounts of consciousness.  Francis Crick (1994), for example, equates human consciousness with synchronized 40-hertz oscillations in the subset of neurons corresponding to an attended object.  Nicholas Humphrey (2011) equates consciousness in general with reentrant feedback loops in an animal’s sensory system.  Such views are not just tepidly unintuitive.  Crick and Humphrey both repeatedly emphasize that non-specialists vigorously resist their views.  Common sense fights them hard.  And common sense fights them hard not just because of the details, although the details make the bizarreness vivid.  Crick writes that his view “is so alien to most people alive today that it can truly be called astonishing” (p. 3).

Another reason to anticipate sharp conflicts between common sense and well developed forms of materialism is that, as I mentioned in section i, common sense has tended to fare poorly beyond practical contexts.  Drawing the dismal induction, it would be surprising if common sense weren’t grossly wrong about some major aspect of the metaphysics of mind – especially considering implications for pathological and science fiction and deep-sea cases.  Philosophers friendly to materialism would be wise, it seems, not to insist on a thorough conformity to common sense.  Indeed they should be eager, like Crick and Humphrey, to abandon poorly founded aspects of common sense.[10]

Early returns in the experimental study of folk attributions of mental states to corporations, robots, and peculiar entities suggest that folk psychology is not a paradise of rigorously principled materialism.[11]  Materialists have ample reason already to suspect serious flaws in the folk psychological materials from which commonsense judgments must ultimately be constructed.  For example, Brian Fiala, Adam Arico, and Shaun Nichols (forthcoming) argue for a dual-process explanation of the folk psychology of consciousness attribution.  They postulate a “low road” cognitive process that attributes consciousness to entities with eyes, non-inertial motion trajectories, and apparently contingent interaction, and they postulate a “high road” cognitive process grounded in deliberate reasoning, including consciously endorsed theories.  Suppose this dual-process model is broadly correct.  One might doubt that either the low-road or the high-road process will map nicely onto any plausible well developed materialist metaphysics.  Even if one process does by happy circumstance map well, the other process – or still some third process, maybe a socio-emotional one – might well still prove powerful enough to generate conclusions contrary to the first and yet felt to have the force of common sense.

I will now illustrate by discussing two specific issues on which I suspect well developed materialist views will be forced into bizarreness.

Mad pain, Martian pain, and beer can pain.  Who in the universe can feel pain?  To judge from the literature, there are currently four viable materialist answers: beings with brains like our own, beings that react to the world in patterns similar to our own, some hybrid view, or some further-mysterious-property view.  To evoke a further mysterious property is not to have a well developed view in the sense of this essay, so let’s set such gestures aside.  The remaining three views all appear to have bizarre consequences.  To insist on brains, that is, on similarity to our own interior physical or biological configuration, seems terribly chauvinistic if we hope to have the whole universe in view and not just our little section of it: Couldn’t a being – an octopus or a space alien? – feel pain despite stark interior differences from us?[12]  Suppose space aliens arrive tomorrow.  They decode English from our television broadcasts and converse fluently with us, behaving much as we do – including withdrawing, screaming, writhing, protesting, avoiding, and revenging when damaged with sharp objects.  They write novels and medical treatises about their agonies, and there’s no reason to doubt their sincerity.  I venture that it would seem bizarre to most people – a weird philosopher’s quibble – to insist that to really be experiencing pain they must also have brains like our own.

As described, these aliens are functionally similar to us, similar in having pain states that play human-like causal roles in their mental economies, and thus (barring the truly fantastic) they must have enough internal structure to underwrite that functional similarity.  Thus functionalism beckons: Maybe the beings in the universe who experience pain are just the beings in the universe who have states that play the causal/functional role of pain.  But such functionalism engenders equally bizarre conclusions, as highlighted by Ned Block (1978/1991) and John Searle (1980, 1984, 1992).  If mentality is all about causal or functional patterns, then weird assemblies of beer cans and wire, powered by windmills and controlling a marionette, could presumably have conscious experience if arranged the right way; and systems composed of rulebooks, slips of paper, and monolingual English speakers could understand Chinese; and genuine mentality might even be possible for economic systems manipulated by wealthy hobbyists, if the fifth derivative of the balance of payments can be made to play the right abstractly defined functional role.  Similarly bizarre are some consequences on the flip side: If pain is all about causal or functional role, then no one could feel pain without possessing some state that is playing the normal causal or functional role of pain.  But it seems simple common sense that one person might enter an experiential state under one set of conditions and might tend to react to it in one way, while another person, or the same person later, might tend to enter the same type of experiential state under very different conditions and have very different reactions.  Madness, pathology, disability, drugs, brain stimulation, personality quirks, and maybe radical Sartrean freedom, can amply scramble, it seems, the actual and counterfactual causes and effects of any experiential state.  So while the brain-oriented view of the previous paragraph seems to be neural chauvinism, insisting that pain is all about causal role appears to be functional chauvinism.  It both attributes pain where it seems bizarre to do so (to beer can systems) and denies possibilities that it seems bizarre to deny (that a person could feel pain for weird reasons and with weird effects).

Maybe both views are too simple.  Maybe we can thread the needle by hybridizing: Beings who experience pain are beings in states with one of a variety of possible biological or physical configurations – just those biological or physical configurations that normally play the causal role of pain, even if things sometimes go haywire.  The word “normally” here can be understood in various ways.  Maybe what matters is that the being possesses some type of physical or biological configuration that plays the required causal role in the right population (e.g., Lewis 1980).  Or maybe what matters is that the configuration played that role, or was selected to play that role, in the developmental or evolutionary history of the organism (e.g., Tye 1995, 2009).  But the appeal to normality implies that pains no longer “supervene” locally: Whether I’m in pain now depends on how my current biophysical configuration is seated in the broader universe – on who else is in my group, or on events in the past.  If normality turns upon the past, then you and I might be molecule-for-molecule identical with each other now, screaming and writhing equally, equally cursing our maker, but because of differences in personal or evolutionary history, I am in pain and you are not.  This would seem to be action at a historical distance.  If pain depends, instead, on what is currently normal for my species or group, that could change with selective genocide or with a speciation event beyond my ken.  Strange forms of anesthesia!  While local nonsupervenience is plausible for relational properties – whether I have an uncle, whether I’m thinking of coffee cup A or qualitatively identical coffee cup B – it is bizarre for pain.

The issue appears to present a trilemma for the materialist: Either accept neural chauvinism (no Martian pain), accept flat-footed functionalism (beer can pain and no mad pain), or deny local supervenience (anesthesia by speciation or genocide).  Maybe some materialist view can evade all three horns; they don’t seem logically exhaustive.  But if so, I don’t see the view out there yet.  It is, I think, a reasonable guess that no plausible, well developed materialist view can simultaneously respect all our commonsense judgments about this cluster of issues.[13]

The consciousness of the United States.  It would be bizarre to suppose that the United States has a stream of conscious experience distinct from the conscious experiences of the people who compose it.  I hope you’ll agree.[14]  (By “the United States” here, I mean the large, vague-boundaried group of people who are compatriots, sometimes acting in a coordinated manner.)  Yet it’s unclear by what materialist standard the United States lacks consciousness.  Nations, it would seem, represent and self-represent.  They respond (semi-)intelligently and self-protectively, in a coordinated way, to opportunities and threats.  They gather, store, and manipulate information.  They show skillful attunement to environmental inputs in warring and spying on each other.  Their subparts (people and subgroups of people) are massively informationally interconnected and mutually dependent, including in incredibly fancy self-regulating feedback loops.  These are the kinds of capacities and structures that materialists typically regard as the heart of mentality.[15]  Nations do all these things via the behavior of their subparts, of course; but on materialist views individual people also do what they do via the behavior of their subparts.  A planet-sized alien who squints might see individual Americans as so many buzzing pieces of a somewhat diffuse body consuming bananas and automobiles, invading Iraq, exuding waste.

Even if the United States still lacks a little something needed for consciousness, it seems we ought at least hypothetically to be able to change that thing, and so generate a stream of experience.  We presumably needn’t go nearly as far as Block does in his famous “Chinese nation” example (1978/1991) – an example in which the country of China implements the exact functional structure of someone’s mind for an hour – unless we suppose, bizarrely, that consciousness is only possible among beings with almost exactly our psychology at the finest level of functional detail.  If we are willing to attribute consciousness to relatively unsophisticated beings (frogs? fish?), well, it seems that the United States can, and does sometimes, act with as much coordination and intelligence, if on a larger scale.

The most plausible materialistic attempt I’ve seen to confine consciousness within the skull while respecting the broadly functionalist spirit of most materialism is Andy Clark’s (2009) and Chris Eliasmith’s (2009) suggestion that consciousness requires the functional achievements possible through high bandwidth neural synchrony.  However, it’s hard to see why speed per se should matter.  Couldn’t conscious intelligence be slow-paced, especially in large entities?  And it’s hard to see why synchrony should matter either, as long as the functional tasks necessary for intelligent responsiveness are successfully executed.

Alternatively, one might insist that specific details of biological implementation are essential to consciousness in any possible being – for example, specific states of a unified cortex with axons and dendrites and ion channels and all that – and that broadly mammal-like or human-like functional sophistication alone won’t do.  As in the case of pain, however, it seems bizarrely chauvinistic to regard consciousness as only possible in beings with internal physical states very similar to our own, regardless of outwardly measurable behavioral similarity.  Or is there some very specific type of behavior that all conscious animals do but that the United States, perhaps slightly reconfigured, could not do, and that is a necessary condition of consciousness?  It’s hard to see what that behavior could be.  Is the United States simply not enough of an “entity” in the relevant sense?  Well, why not?  What if we all held hands?

In his classic early statement of functionalism, Putnam (1965) simply rules out, on no principled grounds, that a collection of conscious organisms could be conscious.  He didn’t want his theory to result in swarms of bees having collective conscious experience, he says.  But why not?  Maybe bee swarms are dumber and represent less than do individual bees – committees collectively act and collectively represent less than do their members as individuals – but that would seem to be a contingent, empirical question about bees.  To rule out swarm consciousness a priori, regardless of swarm behavior and swarm structure, seems mere prejudice against beings of radically different morphology.  Shouldn’t a well developed materialist view eventually jettison unprincipled folk morphological prejudices?  We resist, perhaps, attributing consciousness to noncompact beings and to beings whose internal workings we can see – but most materialist theories appear to imply, and probably part of common sense also implies, that such differences aren’t metaphysically important.  The materialist should probably expect that some entities to which it would seem bizarre to attribute conscious experience do in fact have conscious experience.  If materialism is true, and if the kinds of broadly functional capacities that most materialists regard as central to conscious mentality are indeed central, it may be difficult to dodge the conclusion that the United States has its own stream of conscious experience, in addition to the experiences of its individual members.[16]

That’s the kind of bizarreness I’m talking about.  These two examples illustrate it, but if one or both examples fail, I hope that the general point is still plausible on broad, inductive grounds.  The more we learn about cosmology, microphysics, mathematics, and other such foundational matters, both cosmic and a priori, the grosser the violations of common sense seem to become.  The materialist should expect no lesser weirdness from the metaphysics of the mind.

 

vi.

 

One alternative to materialism is dualism, the view that people are not wholly material entities but rather possess an immaterial soul in addition to their material bodies.[17]  (By “dualism”, unqualified, I mean substance dualism, which posits an immaterial soul.  “Property dualism” I will discuss briefly below.)  Although dualism has merits as a first pass at a commonsense metaphysics of mind, from the 17th century to the present, the greatest philosophers of the Western world have universally found themselves forced into bizarre views when attempting to articulate the metaphysics of immateriality.  I regard this history as significant empirical evidence that a well developed metaphysics of substance dualism will unavoidably be bizarre.

Attempts at commonsense dualism founder, it seems, on at least two broad issues: the causal powers of the immaterial mind and the class of beings with immaterial minds.

The causal powers issue can be posed as a dilemma: Does the immaterial soul have the causal power to affect material entities like the brain?  If yes, then material entities like neurons must be regularly and systematically influenced by immaterial events.  A neuron must be caused to fire not just because of the chemical, electrical, and other physical influences on it but also because of immaterial happenings in spiritual substances.  Either events in the immaterial realm transfer some physical or quasi-physical push that makes the neuron behave other than it would without that immaterial push – which seems to violate ordinary ideas about the sorts of events that can alter the behavior of small, material, mechanistic-seeming things like the subparts of neurons – or the immaterial somehow causally operates on the material despite the fact that material events would transpire in exactly the same way absent that influence, which seems an equally strange view.  Suppose, then, the other horn of the dilemma: The immaterial soul has no causal influence on material events.  If immaterial souls do anything, they engage in rational reflection.  On a no-influence view, such rational reflection could not causally influence the movements of the body.  You can’t make a rational decision that has any effect on the physical world.  This again seems bizarre by the standards of ordinary common sense.  I’ve skated quickly here over some complex issues, but I hope that the informed reader will find that it rings true to say that dualists have perennially faced trouble accommodating the full range of commonsense opinion on mental-physical causation, for approximately the reasons outlined.[18]

The scope of mentality issue can be posed as a quadrilemma: Either (a.) among Earthly animals, only human beings have immaterial souls and they have those souls from birth (or maybe conception); or (b.) there are sharp boundaries in phylogeny and development between ensouled and unensouled creatures; or (c.) whether a being has an immaterial soul isn’t a simple yes-or-no matter but rather a gradual affair; or (d.) panpsychism is true, that is, every being has, or participates in having, an immaterial soul.  Each possibility violates common sense in a different way.  Since on a substance dualist metaphysics of mind, the immaterial soul is the locus of mentality and conscious experience, option (a) denies dogs and apes mentality and conscious experience, contrary to what seems to be the clear opinion of most of humankind.  Option (b) requires sudden saltations in phylogeny and development, which seems bizarre given the smooth gradation of differences in behavioral capacity, both developmentally and across the range of non-human animals, and given the work the immaterial soul must do if it’s not to be otiose.  Option (c) appears incomprehensible from a commonsense point of view: What would it mean to sort of, or kind of, or halfway have an immaterial soul?  (Would you sort of go to Heaven?  Even Dog Heaven, which might be a “sort of” Heaven, seems to require dichotomously either that dogs are materially instantiated there or that they have some immateriality that transcends the grave.)  And despite a certain elegance in panpsychism, the idea, in option (d), that even vegetables and bacteria and proteins and thermostats have immaterial souls, or alternatively that they participate in a single grand immaterial soul, seems bizarre on the face of it.[19]

I don’t intend the arguments of the past two paragraphs as a priori metaphysical arguments against dualism.  Rather, they constitute a proposed diagnosis of an empirically observed phenomenon: the failure of Descartes, Malebranche, Spinoza, Leibniz, Bayle, Berkeley, Reid, Kant, Hegel, Schopenhauer, et al., up to and including contemporary substance dualists like Popper and Eccles (1977) and Foster (1991) to develop non-bizarre views of the metaphysics of immateriality.  Some of these thinkers are better described as idealists than as substance dualists, but the mire of issues they faced was the same, and my explanation of their attraction to bizarre metaphysics is the same: Common sense is a jumble.

You might feel that there exists a well developed substance dualist metaphysics that violates common sense in no major respect and thus is not bizarre in the sense I’ve been using the term.  I can’t treat every philosopher on a case-by-case basis, but let me briefly mention two: Reid, who enjoys some reputation as a commonsense philosopher, and Descartes, whose interactionist substance dualism has perhaps the best initial intuitive appeal.

Reid’s explicit and philosophically motivated commitment to common sense often leads him to refrain from advancing detailed metaphysical views – which is of course no harm to my thesis.  However, in accord with my thesis, on those occasions where Reid does develop views on the metaphysics of dualism, he appears unable to sustain his commitment to common sense.  On the scope of mentality, Reid is either silent or slides far down toward the panpsychist end: He attributes immaterial souls to vegetables (esp. in 1774-1778/1995, 3.X), but it’s unclear whether Reid thinks such immateriality is sufficient for mentality (leading to panpsychism) or not (in which case Reid did not develop a criterion for non-human mentality and so his view is not “well developed” in the relevant sense).  On causal powers, Reid holds material events to be causally epiphenomenal: Only immaterial beings have genuine causal power.  Physical objects cannot produce motion or change, or even to cohere into shapes, without the regular intervention of immaterial beings (1774-1778/1995; 1788/2010).  Reid recognizes that this view conflicts with the commonsense opinions of ordinary people – though this mistake of the “vulgar” does them no harm (see 1788/2010, IV.3).  Despite his commitment to common sense, Reid explicitly acknowledges that on some issues human understanding is weak and common sense errs (see also 1785/2002, I.1).

Descartes, too, can’t quite keep friendly to common sense regarding causal powers and animal souls.  He advocates interactionist dualist approach to causal powers on which activities of the soul can influence the brain.  This view is, perhaps, somewhat less jarring to common sense than some of the other options.  But interactionist dualism does, as noted above, suggest a rather odd and seemingly unscientific view of the behavior of neurons, which is perhaps part of why so many of Descartes’s dualist successors rejected interactionism.  It is also, perhaps, slightly strange to imagine the immaterial soul becoming drunk or caffeinated.[20]  On the distribution of immaterial souls, Descartes occupies the extreme opposite pole from the panpsychist: Only human beings have minds.  Non-human animals, despite their evident similarity to human beings in physiology and in much of their behavior, have no more thought or sensory experience than does a cleverly made automaton.  That Descartes’s opponents could imagine Descartes, in Leiden, flinging a cat out a window as he asserts that animals are mere machines, is testament to the sharp division between Descartes’s and the common person’s view about the consciousness of cats.  (See Grayling 2005, p. 135, for a recent account of this apocryphal event.)  Descartes’s interactionist dualism, on inspection, is no great monument of common sense.

I conclude that we have good grounds to believe that any well developed dualist metaphysics of mind will conflict sharply with common sense on some central issues.

 

vii.

 

The third historically important position is idealism, the view that there is no material world at all but only a world of minds or spirits, in interaction with each other or with God, or wholly solipsistic.  In the Western tradition, Berkeley (1710-1713/1965) and maybe Hegel (1807/1977) are important advocates of this view; some non-Western and mystical thinkers also appear to embrace idealism.[21]  As Berkeley acknowledges, idealism is not the ordinary view of non-philosophers: “It is indeed an opinion strangely prevailing amongst men that houses, mountains, rivers, and, in a word, all sensible objects have an existence, natural or real, distinct from their being perceived by the understanding” (PHK §4).  No one, it seems, is born an idealist.  They are convinced, against common sense, by metaphysical arguments or by an unusual religious or meditative experience.  Idealism also inherits the same bizarre choices about causation and the scope of ensoulment that trouble dualist views: If a tree falls, is this somehow one idea causing another?  Do non-human animals exist only as ideas in our minds or do they have minds of their own; and if the latter, how do we avoid the slippery slope to panpsychism?

The bizarrenesses of materialism and dualism may not be immediately evident, manifesting only when details are developed and implications clarified.  Idealism, in contrast, is bizarre on its face.

 

viii.

 

There might be an alternative to classical materialism, substance dualism, or idealism; or there might be a compromise position.  Maybe Kant’s transcendental idealism (1781/1787/1998) is such an alternative or compromise, or maybe some sort of Russellian (1921, 1927) or Chalmersian (1996) neutral monism or property dualism is.  However, I think we could hardly accuse Kant, Russell, or Chalmers of articulating a commonsense view of the metaphysics of mind, even if there are aspects of their views that accord with common sense better than do some of the competitor views.  Chalmers, for example, offers no good commonsense answer to the problems of immaterial causation and the scope of immateriality, tentatively favoring epiphenomenalism and panpsychism: All information processing systems, even thermostats, have conscious experience or at least “proto-consciousness”, but such immaterial properties play no causal role in their physical behavior.  The attractions of Kant, Russell, and Chalmers lie, if anywhere, in their elegance and rigor rather than their commonsensicality.

Alternatively, maybe there’s no metaphysical fact of the matter here.  Maybe the issue is so ill-conceived that debate about it is hopelessly misbegotten (Carnap 1928/1967; maybe Searle 1992, 2004[22]).  Or maybe asking metaphysical questions of this sort takes us too far beyond the proper bounds of language use to be meaningful.[23]  But this type of view, too, seems bizarre.  The whole famous mind-body dispute is over nothing real, or nothing it makes sense to try to talk about?  There is no fact of the matter about whether something in you goes beyond the merely physical or material?  We can’t legitimately ask whether some immaterial part of you might transcend the grave?  It’s one thing to allow that facts about transcendent existence might be unknowable – an agnostic view probably within the bounds of commonsensical options – and it’s one thing to express the view, as some materialists do, that dualists speak gibberish when they invoke the immaterial soul; but it’s quite another thing, a much more radical and unintuitive thing, to say that there is no legitimate sensible interpretation of the dualist-materialist(-idealist) debate, not even sense enough to allow the materialist coherently to express her rejection of the dualist’s transcendent hopes.

 

ix.

 

I am making an empirical claim about the history of philosophy and offering a psychological explanation for this putative empirical fact.  The empirical claim is that all existing well developed accounts of the metaphysics of mind are bizarre.  The psychological explanation is that common sense is incoherent with respect to the metaphysics of mind.  Common sense, and indeed I think simple logic, requires that one of four options be true: materialism, dualism, idealism, or a compromise/rejection view.  And yet common sense conflicts with each option, either on its face or implicitly as revealed when metaphysical choices are made and implications pursued.  If common sense is indeed incoherent in the metaphysics of mind, then the empirical claim can be modally extended: It is not possible to develop a metaphysics of mind that is both coherent and non-bizarre by the standards of current common sense, if that view involves specific commitments on tricky issues like fundamental ontology, mind-body causation, and the scope of mentality.  Call this thesis universal bizarreness.

Crazyism requires conjoining universal bizarreness with a second thesis, universal dubiety, to which I will now turn.  The universal dubiety thesis is just the thesis that none of the bizarre options compels belief.  At a moderate grain of specificity – say, with three starkly different variants of each of the four broad metaphysical positions – we are left with only dubious choices.  No commonsensical or well justified option remains.

The universal dubiety thesis requires specification of a range of options, lest universal dubiety be either too difficult or too easy to defend.   (Imagine only two options, radical solipsism vs. denial of radical solipsism; or imagine a thousand options including Terrifically Awesome Theory and Terrifically Awesome Theory with a Minor Plausible Twist.)  I am reluctant to stand behind a firm taxonomy of moderate-grain options, but I will suggest an artificially symmetric list of thirteen and then a principle of option construction.  Consider then, three versions of materialism: a liberal one in which conscious experience extends widely through the universe including to fairly simple creatures and/or to aggregate entities like the United States, a conservative one in which conscious experience is much more narrowly confined, and an eliminativist one in which the concept of consciousness is too problematic for this liberal/conservative distinction to make sense.  And consider three versions of dualism: one with mental and material causal interaction, one in which material events causally influence but are not causally influenced by immaterial events, and one in which some intervening agency (e.g., God) ensures the regular conjunction of material and mental events that are not independently efficacious.  And consider three versions of idealism: God-orchestrated Berkeleyianism, grand-world-mind idealism, and solipsism.  And consider three compromise or rejection positions: neutral monism on which there’s only one kind of stuff but it can have both material properties and immaterial properties, transcendental idealism on which beyond the circuit of our experience there are unknowable things-in-themselves not possessed of material properties (e.g., not distributed in space), and broken-concept rejectionism.  Finally consider a catch-all thirteenth position tantamount to the denial of any version of the previous twelve.  These thirteen positions, I submit, are very different from each other – or at least, let’s say, eleven of them are (allowing the possibility that two positions collapse into minor or terminological variants of others).  These eleven-plus positions will be bizarre in very different ways.  And though they are not all epistemically equal, I will argue below that it is probably not epistemically rational to regard any one of the positions as more likely to be true than false – that is, as more likely than all the competitor positions combined.

As I said, I’m not committed to this particular taxonomy.  What’s important is that the positions involve very different metaphysical stories, with very different bizarrenesses.  The advocate of universal dubiety should be at liberty to construct a taxonomy of choice in accord with a principle of very large differences.[24]  Universal dubiety is the view that there is at least one such taxonomy in which no option merits credence above 50%.

 

x.

 

An Argument from Authority and Maybe Peers.

Let’s assume that you, reader, are not among the world’s leading metaphysicians of mind.  And let’s assume that you’re drawn toward some particular metaphysics of mind other than David Chalmers’s property dualism.  It seems likely that David Chalmers, who is one of the world’s leading metaphysicians of mind, and who is by all accounts highly intelligent and well read, could run argumentative rings around you, including pointing out relevant considerations of which you are now unaware.  Any unbiased referee would call a knockout in the first or second round.  Given that fact, how confident should you be in your opinion?  Or suppose you’re drawn toward something like the Chalmers view after all.  Likely David Lewis could have run rings around you, defending his version of materialism.  Last summer, I described various metaphysical options to my then eleven-year-old son (yet another David).  Davy immediately adopted one position against all others, and he refused to be budged by my counterarguments.  It seems a kind of epistemic failing – although also, in a different way, a kind of intellectual virtue that will serve him well in his education – for Davy to be confident in his view.  He barely even understood the issues, much less had a deep appreciation of the arguments.  If you or I stand confidently against the giants, armed only with our weaker comprehensions, are we so different from Davy?  Some of us might happen to have the right view, maybe even because we are sensitive, as others of us are not, to the real considerations that decisively favor it; but in some epistemically important sense that’s just luck.

Suppose that’s a fair assessment of the epistemic situation in your own case in particular.  What should you do about it?  Read enough philosophy to become one of the world’s leading metaphysicians?  Even if that weren’t hopelessly impractical, it wouldn’t settle what your attitude should be right now, which is the question.  Should you simply, then, bow to expert opinion, as one might bow to the expert opinion of a chemist about the electronegativity of fluorine?  That doesn’t seem right either.  For one thing, there is no consensus expert opinion to bow to.  For another, on an issue as central to one’s worldview as mind and body (especially because of its connection to religious belief), and as subject to preconception and bias even among experts, it may be wise not to cede one’s intellectual autonomy.  I recommend this: Spread your confidence distribution broadly enough that your credence in your own favored view (at a moderate grain of specificity) does not exceed your estimation of the likelihood of all other competing positions combined.  For those of us who are not among the world’s leading metaphysicians of mind, the sweet spot between autonomous self-confidence and appropriate intellectual humility is, I submit, somewhat south of a 50% credence in that favored view.

If I’m fortunate, some readers will be among the world’s leading metaphysicians of mind.  To you, this argument does not apply.  However, there may be a parallel argument cast in terms of disagreement among epistemic peers.[25]  I’m not sure the argument from peers rationally compels a credence below 50% for your favorite moderately specific metaphysics of mind, though I’m inclined to think that it most cases it does.  Even if it doesn’t, though: On the assumption that expert readers spread their opinions diversely among several of the more popular metaphysical options, most expert readers must be wrong.

The force and scope of my universal dubiety claim is this: Probably, on empirical grounds, we are not currently epistemically warranted, nor will we in the near-to-medium-term future be warranted, in assigning greater than 50% credence to any one metaphysical option, at a moderate grain of specificity.  For the argument from authority and maybe peers the scope of the “we” is important.  By “we” I mean the philosophical community as a whole and most of the notional readership of this essay.  Implacable, long-term disagreement among the best-informed experts, with no one option accepted by a majority of experts and no foreseeable hope of resolution, is good reason to accept the universal dubiety thesis.

The present argument might seem to generalize to most of philosophy.  I’m inclined to think it does generalize, but not as much one might think.  In areas of progress and discovery (logic, historical interpretation, evaluation of the consequences of specific argumentative moves, empirically driven inquiries, newly opened issues) the peers version, at least, breaks down: One might have good grounds for thinking oneself early to the discovery.  And perhaps non-experts, too, can avail themselves of those same grounds.  The argument will also fail to generalize to issues on which pluralism is warranted – cases in which multiple conflicting approaches can have approximately equal merit, such as perhaps in the articulation of visions of the good life or in goal-relative pragmatic recommendations for the adoption of particular conceptual structures.  What’s left, perhaps, are only the grand, timeless, factual disputes that continually defy us and on which the experts are widely dispersed.  These disputes can probably be counted on two hands.

Is the argument objectionably authoritarian or defeatist?  I hope not.  I am not saying: You’re not entitled to an opinion where the experts (or your peers) disagree.  One may still have a favored view.  I hope you do.  One might even “accept” that view, in the pragmatic sense of treating the view as a basis for action and further reflection.[26]  I advise not deference or despair but rather autonomy thoroughly salted with a sense of one’s limitations.  The failures of millennia of philosophical ambition, and the discord among thousands of currently-living PhD’s, should humble us all.

 

 

xi.

 

A No-Method Argument.

There is no conscious-ometer.  Nor should we expect one soon.  There is also no material-world-ometer.  The lack of these devices problematizes the metaphysics of mind.

Samuel Johnson kicked a stone.  Thus, he said, he refuted Berkeley’s idealism (Boswell 1791/1980, p. 333).  Johnson’s proof convinces no one with an inkling of sympathy for Berkeley, nor should it.  Yet it’s hard to see what empirical test could be more to the point.  Carnap (1928/1967, p. 333-334) imagines an idealist and a non-idealist both measuring a mountain; there is no experiment on which they will disagree.  No multiplicity of gauges, neuroimaging equipment, or particle accelerators could give stronger empirical proof against idealism than Johnson’s kick.  Similarly, Smart, in his influential defense of materialism, admits that no empirical test could distinguish materialism from epiphenomenalist substance dualism (1959, p. 155-156); there is no epiphenomenal-substance-ometer.

Why, then, should we be materialists?  Smart appeals to Occam’s razor: Materialism is simpler.  But simplicity is a complex business.[27]  Arguably, Berkeley’s idealism is simpler than either dualism or materialism and solipsism simpler yet.  And anyhow, simplicity is at best one theoretical virtue among several, to be balanced in the mix.  If most of the metaphysical contenders are empirically indistinguishable, then it seems we must turn to some combination of common sense and abstract theoretical virtue to settle the issue.  Abstract theoretical virtues like simplicity will, I suggest, attach only indecisively, non-compellingly, to the genuine metaphysical contenders.  I’m not sure how to argue for this other than to invite you sympathetically to feel the abstract beauties of some of the contending views other than your favorite.  If the arguments of the first several sections of this essay are correct, common sense is also incapable of furnishing compelling grounds for choice of a single winner among the options.

We might still imagine at least a conscious-ometer that we could press against a human or animal head to decide among, say, relatively conservative vs. moderate vs. liberal materialistic views of the abundance or sparseness of consciousness in the world.  But even this is too much to hope for, I think, in the near to medium term.  Is a frog conscious?  That is, does a frog have a stream of phenomenal experience?  Is there something it’s like to be a frog?  If two theorists of consciousness disagree about this matter, no output from an fMRI scanner or similar is likely to resolve their disagreement – not unless they share much more in common than conservatives and liberals about the abundance of consciousness generally do share.  Nor can a frog report its experience or lack of experience in any straightforward way.  Similarly intractible, I think, is the dispute about whether, for example, people have constant tactile experience of their feet in their shoes.[28]  If so, we have no firm grounds of choice between approaches to consciousness that are relatively liberal (perhaps even as liberal as panpsychism) and approaches that are relatively conservative (perhaps even as conservative as restricting consciousness to adult human beings in their more self-aware moments).  Nor, I think, do we have good grounds to deny that liberal and conservative views are different enough to constitute very different metaphysical pictures.  Maybe some disputes among materialists are merely terminological (certain forms of functionalism vs. certain forms of identity theory?).  Not the abundance dispute, though; at least not always.  Either there’s something it’s like to be a frog, or there isn’t, or somewhere in-between, or the question is somehow broken.  These are substantially different positions, each with some ineliminable plausibility and no broadly acceptable means of empirical test.

Thus I suggest: Major metaphysical issues of mind are resistant enough to empirical resolution that none, at a moderate grain of specificity, empirically warrants a degree of credence exceeding that of all competitors; and this situation is unlikely to change in the foreseeable future.  Neither do these issues permit resolution by appeal to common sense (which will rebel against all and is probably a poor guide anyway) or by appeal to broad, abstract theoretical considerations.  I assume there are no logical self-contradictions in any of these views, at least insofar as they are well developed real contenders.

Is there some other means of settling the matter that I am overlooking?

 

xii.

 

An Argument from Cosmological Crazyism.

If a broad-reaching cosmological crazyism is true, then crazyism in the metaphysics of mind is a natural consequence.  If we don’t know how the universe works, we don’t know how the mind fits within it.

I can’t defend cosmological crazyism in detail here, but a few remarks can highlight its plausibility.  Consider the bizarreness of quantum theory and the lack of consensus about its interpretation, including the fact that some interpretations treat mentality as fundamental (such as the many minds view and some versions of the Copenhagen interpretation[29]).  Consider the bizarreness of relativity theory, perhaps especially the relativistic concept of distance, and the apparent willingness of a portion of the physics community in 2011 to contemplate its overthrow given a single report of apparently faster-than-light neutrinos.[30]  Consider, too, the apparent conflict between relativity theory and quantum theory.[31]  Consider that many cosmologies now posit either a creator who set the physical constants at the time of the Big Bang so as to support the eventual occurrence of life, or a vastly unlikely chance setting of those variables, or some sort of dependence of the universe upon our observation of it, or the real existence of a vast number of universes (or aeons of this universe) with different physical constants.[32]  The last of these four views – broadly, multiverse theory – seems to be a recent favorite.  Prima facie, multiverse theory is both dubious and bizarre.  Here’s one among the bizarrenesses: If the number of universes is infinite, or if there is even a single infinite universe, then every event of finite probability will occur an infinite number of times (given certain background assumptions about probability and cosmic diversity).  The spontaneous congealment of a molecule-for-molecule twin of any living person is often held to have a very tiny but finite probability.[33]  You would, then, be one among an infinite number of actually existing molecule-for-molecule twins of yourself, of diverse origin.  Quantum cosmology has also been interpreted as suggesting the backward causation of the history of the universe by our current acts of scientific observation (e.g., Hacking and Mlodinow 2010, p. 140).

Shall we look, then, to religion for non-bizarre cosmologies?  That seems an unlikely source.  Creation stories, accounts of the afterlife – especially in the hands of those who would attempt to work out the full ontological implications – seem only a source of further bizarreness.

Another difficulty is this: If consciousness can be created within artificial networks manipulated by external users – for example, but not necessarily, in computer programs run by children for entertainment – and if the beings inside those networks can be kept ignorant of their nature, then there could be beings in the universe who are vastly deluded in fundamental matters of metaphysics.  Such beings, perhaps, might think they live in a wide world of people like them when in fact they have three-hour lives, isolated from all but their creator and whatever other beings are instantiated in the same artificial environment.  There is, I think, a non-negligible possibility that we (I?  you?) are such beings.[34]  Suppose in the year 2200 a new computer game is released, Sims 2012, and it’s a huge hit.  A hundred million children buy it.  Each instance of Sims 2012, when run, creates a hundred thousand actually conscious simulated people, each of whom thinks she is living in the early 21st century and has an appropriate range of apparent memories and apparent sensory experiences.  In reality, these people serve mainly to provide entertaining reactions when, to their surprise, Godzilla tromps through.  Possibly, if the economics of technology plays out right, there are many more such simulated beings in the universe than there are non-simulated beings.  The details don’t matter of course, whether the outside agents are children or historians or scientists, Earthly beings or gods or aliens running an Earth fiction.  Might we be Sims of broadly this sort?  To think that we are in fact Sims is, I concede, crazy.  But is the possibility too crazy to figure in a disjunction of live cosmological options?  Is it more than one order of magnitude crazier than multiverse theory or the typical well developed religious cosmology?  There are no commonsense cosmologies left.

Further support for cosmological dubiety comes from our (apparently) miniscule cosmological perspective.  If mainstream scientific cosmology is correct, we have seen only a very small, perhaps an infinitesimal, part of reality.  We are like fleas on the back of a dog, watching a hair grow and saying, “Ah, so that’s how the universe works!”

There seems to me to be sufficient cosmological uncertainty to cast into doubt any metaphysics of mind with cosmological commitments.  And all well developed metaphysical accounts of the mind will have cosmological commitments, if only in the choice between materialism, dualism, idealism, or a compromise/rejection view.  For example, if it might be the case that an immaterial entity fashioned the physical constants, then we cannot justifiably rest assured that materialism is true.  If there might really exist universes (not just “possible worlds” but actual universes) so radically different from our own that cognition transpires without the existence of anything we would rightly call material, then materialism is at best a provincial contingency.  If we are created within a simulation by outside agents, our experience of objects as necessarily laid out in space and time might be a feature of our programming environment that doesn’t reflect the fundamental ontology of the universe (Kant meets cyberpunk).

Scientific cosmology is deeply and pervasively bizarre; it is highly conjectural in its conclusions; it has proven unstable over the decades; and experts persistently disagree on fundamental points.  Nor is it even uniformly materialist.  If materialism draws its motivation from being securely and straightforwardly the best scientific account of the fundamental nature of things, materialists ought to think twice.  I focus on materialism, since it is the dominant view in contemporary metaphysics of mind, but similar considerations cast doubt on dualism, idealism, and at least some of the compromise/rejection views.

 

xiii.

 

Certain fundamental questions about the metaphysics of mind cannot be settled by science, in its current state, or by abstract formal reasoning.  To gain purchase on these questions we must depend to a considerable extent on common sense.  If we then have good reason to think that common sense, too, is no reliable guide, we are unmoored.  Without common sense as a constraint, the possibilities open up, bizarre and beautiful in their different ways; and once open they refuse to shut.  This is crazyism.

Does it follow that you don’t know that you are on Earth, reading philosophy?  Does crazyism collapse into radical skepticism?  I hope not.  Earth might actually be SimEarth, or nothing but a constellation of ideas in the mind of God – its fundamental nature might be very different than you are inclined to suppose – but even in such transparently bizarre metaphysical or cosmological stories, Earth exists.[35]  In even more stories, the computer screen or piece of paper you are looking at exists.  Nothing I have said implies, I think, that it is unreasonable to distribute most of your credence to Earth-involving stories over Earth-denying ones.  And then, maybe, if Earth does exist, and if your belief that it does has arisen in the right manner or has the right kind of support, you will qualify as knowing that fact.[36]

 

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            [1] For example, Frege 1884/1953; Lewis 1986; Yablo 1987.

            [2] Critiques of the role of common sense or philosophical intuition as a guide to metaphysics and philosophy of mind can be found in, for example, Churchland 1981; Stich 1983; Gopnik and Schwitzgebel 1998; Kornblith 1998; Dennett 2005; Ladyman and Ross 2007; and Weinberg, Gonnerman, Buckner, and Alexander 2010.  Hume 1740/1978 and Kant 1781/1787/1998 are also interesting on this issue, of course.  Even metaphilosophical views that treat metaphysics largely as a matter of building a rigorous structure out of our commonsense judgments often envision conflicts within common sense so that the entirety of common sense cannot be preserved: e.g., Ayer 1967; Kriegel 2011.

            [3] DeWitt, for example, writes:

I still recall vividly the shock I experienced on first encountering this multiworld concept. The idea of 10100+ slightly imperfect copies of oneself all constantly splitting into further copies, which ultimately become unrecognizable, is not easy to reconcile with common sense (1970, p. 33).

            [4] Recent reviews of the difficulties in settling among various bizarre interpretations include Penrose 2004; Wallace 2008.

[5] See, e.g., Hempel 1980; Chomsky 1995; Montero 1999; Stoljar 2010.

            [6] Although Searle rejects the dualism-materialism distinction, I believe he is materialist in the vague sense of the previous paragraph.  See, e.g., Searle 1995, pp. 6-7.

            [7] In the General Social Survey of Americans in 2010 (http://www3.norc.org/GSS+Website; accessed September 16, 2011), 72% of respondents reported believing in life after death and 17% reported disbelieving; 75% reported believing in God, 11% reported belief in an impersonal “Higher Power”, and only 3% reported atheism.  We can probably safely assume that most contemporary American theists are not materialists (though some may be: Baker 1995; Murphy 2006).  Some other industrialized Western nations are more secular than the U.S., but even in those societies religiosity is widespread (Zuckerman 2007), and religiosity or belief in entities not tolerated by materialism might even be something like a cultural universal (Brown 1991; McCauley 2000; Boyer 2001).  Paul Bloom (2004) has argued on developmental and cross-cultural grounds that it is innately natural to human beings to think of mental life as the product of an immaterial soul, even if some of us reject dualism on an “airy intellectual level” (see also Richert and Harris 2006; Hodge 2008; Slingerland and Chudek 2011).  In David Bourget’s and David Chalmers’ 2009 PhilPapers survey of faculty in leading Anglophone philosophy departments, 62% of respondents reported accepting atheism and another 11% reported “leaning toward” it.  Yet even in this remarkably secular group, only 35% reported accepting and 22% reported leaning toward physicalism (http://philpapers.org/surveys; accessed September 19, 2011).

            [8] See, e.g., Campbell 1970; Kirk 1974; Chalmers 1996.

                [9] See, e.g., Levine 1983, 2001; Chalmers 1996; Ramsey 2006; Robbins and Jack 2006.

            [10] See, e.g., Churchland 1981; Stich 1983; Metzinger 2003; Dennett 2005; Mandik and Weisberg 2008. 

            [11] Gray, Gray, and Wegner 2007; Knobe and Prinz 2008; Huebner, Bruno, and Sarkissian 2010; Sytsma and Machery 2010; Buckwalter and Phelan 2011.

            [12] This thought is central to early functionalist arguments against identity theory materialism, e.g., Putnam 1965; Fodor 1974.  For discussion and criticism see Bechtel and Munsdale 1999; Shapiro and Polger forthcoming.

            [13] See also Adams and Dietrich 2004.  See Hill 2009 for a rather different argument that the folk metaphysics of pain is incoherent.

            [14] Admittedly, the willingness of English-language speakers to ascribe mental states of various sorts to corporate entities is empirically complex.  See Knobe and Prinz 2008; Sytsma and Machery 2009; Arico 2010; Huebner, Bruno, and Sarkissian 2010.

                [15] E.g., Fodor 1987, 1990; Dennett 1987, 1991; Churchland 1984/1988; Dretske 1988, 1995; Lycan 1996; Tononi 2004; Carruthers 2005; Rosenthal 2005; Hill 2009; Humphrey 2011.  Even materialists who emphasize the identity of mental states and brain states will normally see functional or causal structures of this sort as what it is that makes brain states the kinds of states that are conscious while the internal states of, say, a toaster are not: e.g., Armstrong 1968; Bechtel and Mundale 1999.  Searle (1984, 1992) seems to be an exception to the tendency described here, though I find his positive position on the biological causes of consciousness too indeterminate in its commitments to fully evaluate on the present issue.

            [16] See also Strawson 1959, p. 113-115; Combs and Krippner 2008; Huebner 2011.

            [17] “Immaterial soul” is intended here in a fairly broad but traditional sense.  By this criterion, some metaphysical systems that call themselves substance dualist, notably Lowe’s (2008), do not qualify.  Despite Lowe’s choice of label his system is very different from traditional substance dualist approaches and for current purposes is probably better conceived as a compromise position.

            [18] Patterson 2005 usefully compares historical and modern approaches to this issue.

            [19] The same quadrilemma arises if immateriality is regarded as essential to life, as on the types of vitalist theories that were discarded in the early 20th century and on immaterialist views of the “vegetative soul”.  As Pierre Bayle nicely articulates, even accepting something like a sharp-boundaried immaterialist vitalism about life doesn’t prevent this complex of issues from arising concerning the “rational soul”, or mindedness, or conscious experience (1697/1702/1965, “Rorarius”; see also Des Chene 2006).

            [20] See especially La Mettrie (1748/1994).  The power of these two examples is that alcohol and caffeine appear to affect the reasoning process itself and not only the passions and bodily movements, contra Descartes’s picture of how bodily influences can oppose reason (1649/1985, esp. §47).

            [21] See especially the Indian Advaita Vedanta and Yogacara traditions – though these traditions present some of the same interpretative challenges as Hegel, probably involving strands better interpreted as a type of compromise or rejection view.  See Deutsch 1969/1973; Deutsch and van Buitenen, eds., 1971; Collins 1998; Lusthaus 2002; Trivedi 2005.

            [22] However, despite Searle’s self-description I would classify Searle as broadly speaking a materialist (see note 6).

            [23] This might seem a broadly Wittgensteinian position, but it’s probably not Wittgenstein’s own position; see esp. 1945-1949/1958, p. 178, and 1947/1980, vol. 1, §265.

            [24] Contrast Bennett’s (2009) small-differences approach to metaphysical epistemic pessimism.

            [25] On the epistemology of peer disagreement see, e.g., Foley 2001; Kelly 2005; Feldman 2006; Enoch 2010.

            [26] E.g., Van Fraassen 1980; Cohen 1992; Bratman 1999.

            [27] E.g., Hempel 1966; Forster and Sober 1994.

            [28] For example, Dennett 1991 vs. Searle 1992.  I suspect that most readers will find the medium-term irresolvability of this latter dispute to be less plausible prima facie than in the between-species case.  I defend my pessimism about this issue at length in Schwitzgebel 2011.

                [29] Wigner 1961; Albert and Loewer 1988; Albert 1992; Faye 2008.

            [30] Neutrino result reported in OPERA collaboration 2011.  For some scientific community reaction see Brumfiel 2011; Matson 2011.

            [31] Famously noted in Einstein, Podolsky, and Rosen 1935 and Bell 1964.  For a recent discussion see Maudlin 1994/2002.

            [32] The is the “fine-tuning” issue.  See Barrow, Morris, Freeland, and Harper, eds., 2008; Hawking and Mlodinow 2010; Penrose 2010; and contra Stenger 2011.

                [33] For discussion: Bousso and Freivogel 2007; Page 2008; De Simone, Guth, Linde, Noorbala, Salem, and Vilenkin 2010.  Such people, or brains, or people-plus-sections-of-environment, have been dubbed “Boltzmann babies” or “Boltzmann brains” after the 19th century physicist, Ludwig Boltzmann, who argued that in a universe of sufficient size any arbitrary low-entropy event – including presumably the congealment of a person – could be expected to occur by chance (e.g., Boltzmann 1897).

            [34] Bostrom 2003; also Chalmers 2003.

            [35] See Berkeley 1710-1713/1965; Chalmers 2003.

            [36] Thanks: Ned Block, Fred Dretske, Chris Hill, Bryce Huebner, Pete Mandik, Jozef Muller, Alan Tapper, Splintered Mind readers, ****.