Ontological Reduction

Is consciousness ontologically irreducible? Richard Brown thinks that the question is incoherent:

What [the identity theorist] says is that there is only ONE thing there, the brain and its various states, and you cannot reduce something to itself!

He goes on to contrast this with linguistic, theoretical reductions, and explains how those are irrelevant to the debate between physicalists and dualists. I agree with that part. But I think he's wrong to think that linguistic reductions are the only coherent form of reduction.

We can see this because, as I've been saying all along, the question is whether qualia are reducible in the same sense that tables and chairs are, whatever that may be. Now, it's an open question whether our talk of tables and chairs could be replaced by (perhaps complicated and long-winded) talk purely in the language of microphysical theory. But we don't care about talk. What matters is that the facts about tables are obviously settled by the microphysical facts. If you have a coarse-grained conception of 'facts', maybe they are even one and the same fact. Even so, we can get to a metaphysical notion of reduction by appeal to the truthmakers for our sentences. Regardless of whether table talk is linguistically replaceable by particle talk, there's no question that the microphysical facts are what make our table statements true (if they are true).

Once you've included the microphysical facts in your base facts, you do not need to add any further 'table facts' in addition. Those are already covered. It is in this sense that table facts are reducible to physical facts. And it is in this sense that the question of physicalism comes down to the question whether qualia are reducible. It is simply the question whether we need to add phenomenal facts to our fundamental base facts, or whether they "come along for free" (like tables do) given the physical facts P.

(I find it convenient to use the term 'reducible' to invoke this idea, but you're of course free to pick another word if you prefer. What's not helpful is to simply insist, "the debate between the dualist and the materialist is in no way a debate about reduction", and so ignore my underlying idea concerning what the debate is about. RB wanted to focus on what counts as 'physical' or 'non-physical', but that soon degrades into semantics. The substantive issue, as I see things, is whether we must include qualia as an additional primitive among the base facts. This understanding makes it clear why RB's "non-physical zombie" parody argument falls flat (to put it mildly). See my 'Zombie Review' for more detail.)

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Zombie Review

Bring out your [un]dead! After all my narrowly focused posts on the topic, it's time for a "big picture" review of the zombie argument against physicalism. Recall: Physicalists think that the physical facts exhaust the base facts: just as the arrangement of particles suffices to settle whether there are tables, so it suffices to settle whether there is conscious experience. So let 'P' denote their complete microphysical description of the world, which makes no explicit reference to phenomenal experience or qualia. Let 'Q' be a statement explicitly about my qualia. The classic argument for dualism thus follows:

1. (P & ~Q) is ideally conceivable [can't be ruled out a priori]
2. If (P & ~Q) is ideally conceivable then (P & ~Q) is possible.
3. If (P & ~Q) is possible then physicalism is false.
Therefore, physicalism is false.

(3) is analytic: if you can have P without Q, then P does not suffice for Q, contrary to the physicalist's claims.

(2) is the premise most philosophers [as "type B materialists"] have traditionally questioned. It raises complicated issues in the metaphysics of modality and philosophy of language which I addressed in depth for my ANU honours thesis: 'Modal Rationalism'. (But you can get the short version here.) The upshot is that denying this step is ad hoc and ultimately commits you to the unmotivated claim that there are coherent scenarios which do not correspond to any possible world. I won't address it further here.

The blogospheric discussion has instead focused on premise (1). I think the intuitive force of the premise is made especially vivid by the zombie thought-experiment, whereby we imagine a world physically like ours but lacking in consciousness. That sure seems conceivable, but type-A materialists are committed to denying this, and claiming instead that there is some implicit contradiction which renders the zombie scenario incoherent. Unfortunately, nobody seems to have any idea what this elusive contradiction might be. (Unless you count Eliezer's suggestion, but that was based on a demonstrably false premise in the philosophy of language.)

Brandon made the reasonable point that we're not in a position to assess (1) with total confidence because we don't yet know what the statement P of completed microphysics says. That's a fair point; I certainly don't think this is a knock-down argument. But we do the best we can from our position of uncertainty, and it seems to me that we have more reason to believe (1) than its negation. So we should lean more towards property dualism, pending further evidence.

Some of the other objections that have been raised are, I think, simply confused. For example, Tanasije worries that epiphenomenalists will have no high-level explanation of our 'consciousness'-related behaviour (e.g. my writing this blog post). But we have no fewer resources than the physicalist, we just use different words to describe them. So while I would deny that zombies have beliefs about consciousness, there is a functionalist analogue (or physical component) of belief, which we may call 'z-belief', which can be cited by third parties and will do all the same scientific/explanatory work. (This raises more interesting worries about whether zombie brains are somehow 'malfunctioning' by z-believing in consciousness, which I address in my post: Zombie Rationality.)

Then there's Richard Brown's attempt at constructing an analogous "non-physical zombie" argument (replacing 'P' with 'NP' above) against dualism. But that won't work for the following reason: (i) Either 'NP' explicitly states the qualia facts Q, or it does not. (ii) If it does, then (NP & ~Q) is straightforwardly contradictory, so the first premise fails. (iii) Otherwise, the third premise fails. The possibility of (NP & ~Q) is compatible with dualism, because the dualist never claimed that those other non-physical facts NP suffice for consciousness. So, either way, it's a terrible argument.

Conclusion

As noted in my original post on the current blogospheric dispute, there are some bullets to bite either way.

The [type-A] materialist must simply have faith that there is an implicit contradiction somewhere in the zombie scenario, even though it shows no sign of such incoherence. They must also trust that third-personal scientific inquiry into non-experiential facts will somehow turn out to imply first-personal experiential facts in the same way that it implies the facts about ordinary macro objects like tables and chairs.

The epiphenomenalist, on the other hand, must explain how we can know that we're conscious if it has no causal effect. This will naturally lead to certain views about belief content and epistemology that others might balk at.

I don't think it's obvious how to weigh these various considerations. Personally, I lean towards epiphenomenalism -- the implications don't strike me as particularly worrisome. But your mileage may vary.

[There are also other views [PDF] on the table, e.g. interactionist dualism and panprotopsychism, but I won't address them here.]

P.S. Don't miss the zombie song - 're: your brains' [ht: Chris].

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Constraining Qualia

[See 'Zombie Rationality' for background.]

A correspondent writes:

Consider the brain of a human looking at three colored balls, which are red, blue, and green respectively. Then a trustworthy logically omniscient agent comes along and truthfully says the following:

1. Brains like this brain, faced with balls like these in the absence of logically omniscient intervenors, engage in information processing that results in inner z-representations to the effect that the red, blue and green balls are inducing different qualia. This typically results in utterances like "when I see these three different balls they look phenomenally red, blue, and green."
2. Across possible non-zombie worlds, in 10% there are indeed different qualia or phenomenal colors for each of the balls, while in 90% the red and blue balls have the same phenomenal color, which is distinct from the phenomenal color of the green ball.

In this case, and using your account, wouldn't the brain maximize the likelihood that its z-beliefs would result in true beliefs by z-believing that it sees only two phenomenal colors rather than three?

Sure (assuming that the measure of a priori credibility over these worlds mirrors the 10/90 split). But it's like a case where an angel tells you that experiences like yours are most likely to be non-veridical because an 'evil demon' or BIV world is objectively more probable than true Earth. If that claim really is true, then sure, I guess you should disbelieve your senses in such a case. But it's highly implausible.

The thought experiment raises a more interesting issue though: might there be constraints on the bridging laws that convert physical configurations into qualia? Although you can have any physical arrangement without corresponding qualia (cognition without mentality), it's not so clear that you can have any old qualia without corresponding computations (mentality without cognition). That is, we might doubt whether 'raw phenomenal feel' can hold entirely independently from the rest of our mental economy. Instead, it may be that in order to see two balls as the same colour, one must also be disposed to judge that they are the same colour, etc.

On this picture, then, you can either have a zombie world with no qualia at all, or else qualia that correspond appropriately to physical structures (which may still allow for some variation, e.g. colour inversion). But there's no sense to be made of free-floating qualia that are thoroughly out of sync with the physical computations that are going on in the world.

(I don't have any arguments for this view. I'm not even sure whether it's well-motivated. I just thought I'd throw the idea out there and see what others think...)

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How To Imagine Zombies

Some of the recent discussion on other blogs has assumed a sloppy version of the zombie argument, whereby we are to imagine a world just like ours but subtract consciousness. Hence Eliezer complains:

The epiphenomenalist imagines eliminating an effectless phenomenon, and that separately, a distinct phenomenon makes Chalmers go on writing philosophy papers. A substance dualist, or reductionist, imagines eliminating the very phenomenon that causes Chalmers to write philosophy papers.

Right, so that's a bad way to present the argument. The better way to imagine the zombie world is not by subtraction, but by building it up. Give a complete microphysical description of the world, and specify "that's all". A Laplacean demon can infer that the world contains tables, brain states, and a book entitled 'The Conscious Mind'. That is, the world contains particles arranged table-wise, brain-wise, book-wise, etc.

The Laplacean demon knows all that there is to know about this world. Does he know that it contains phenomenal consciousness, that there is something it is like to be the particles-arranged-humanwise in this world? Seems not. There's nothing in the microphysics that entails the presence of such subjectivity. So we've successfully imagined the zombie world. Not by subtracting, but by building up from the physics alone and noting that more needs to be added in order to obtain our (consciousness-containing) world.

Richard Brown makes a similar mistake in his attempted parody:

I am conceiving of a world that is just like this one in all non-physical respects except that it lacks consciousness. Therefore dualism is false.

The zombie argument begins by providing an undisputed specification of the "physical respects" of the world. It then asks whether phenomenal consciousness logically follows from the specification. Our answer is 'no'. That's why physicalism is false.

A proper analogy, then, would require building up the "non-physical zombie" world from an undisputed non-physical specification, just as we earlier built up a physical zombie world from an undisputed physical specification. But of course RB cannot do this. So that's why the zombie argument cannot be turned against dualism in this way.

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Zombie Rationality

'Zombie' writes:

On Chalmers' view, wherein the 'psychophysical laws' are contingent, it seems that across possible worlds most brains like ours will be zombies or at least have 'associated' qualia that don't 'match' the information processing in the brain. So sophisticated brains proceeding according to ordinary standards of rationality should zombie-conclude that they probably are not conscious (as they don't have access to any non-material qualia), despite their zombie-perceptions of being conscious (shared by both zombie and non-zombie brains). Yet Chalmers thinks that in our actual world the psychophysical laws lead to conscious experience mirroring the information processing in the brain. So, upon hearing the argument, shouldn't Chalmers' brain zombie-conclude that it is probably a zombie brain, and 'phenomenal Chalmers' consciously think the same?

No. Conclusions are drawn by people, not brains. Standards of rationality likewise apply to agents and their beliefs, not to their physical components (brains and neural states) in isolation.

On my view, beliefs are partly constituted by phenomenal properties -- that's what gives them their representational content. Zombies don't have beliefs like we do. They exhibit all the same behaviour, and make all the same noises, but there's no meaning in it. It's not really about anything.

One might define a 'z-belief' as the functional (physical, dispositional) component of a belief. It's not so clear how to assign pseudo-contents to these z-beliefs, but I guess a reductionist may offer a stipulation of some kind: S has a z-belief that P iff S has such-and-such physical dispositions [e.g. 'S behaves as though P were true', or 'S has a brain state which covaries with evidence of P', or some such. See my essay 'What Behaviour is About' for a more sophisticated empirical approach to attributing "content".]

Presumably we're to suppose that whenever I really have the belief that P, my brain has the z-belief that P. But I doubt whether any such reduction can be given that perfectly mirrors my actual belief contents. (If epiphenomenalism is true, and qualia are partly determinative of belief content, then the physical facts underdetermine what it is that I believe. My inverted-spectrum duplicate has the same brain -- hence z-beliefs -- as me, but our phenomenal beliefs are very different. My 'red' is his 'blue', or whatever.)

There's a more fundamental problem, even if we grant the reductionist his impossibly fine-grained z-content. Let's grant - per impossibile - that my brain (and zombie twin) "z-believes that P" iff I believe that P. However, my brain (understood as a purely physical system, i.e. excluding its phenomenal properties) is in possession of only a subset of my total evidence. Qualia - the contents of experience - are among my evidence if anything is. But these phenomenal properties are not causally accessible to my neural processes. So the conclusion 'I am conscious' follows from my evidence, but not from the "information" available to my brain. One can be a rational person, or have a "rational" brain, but not both.

Now, it's pretty obvious that being a rational person is better than having a "rational brain" (insofar as the latter attribution is even meaningful). Brains are parts of people, and like any body part we really only care about it for how it can serve the whole person. If quick feet didn't make for a quick person, we wouldn't much care for the former. Similarly, a rationally desirable brain is one that makes for a rational person, with justified beliefs.

One could imagine a brain that is instead built in such a way that it tends to produce "z-justified" z-beliefs. What this means is that it tends to end up in physical states such that a conscious person in that physical state would have beliefs in line with the physically accessible subset of their evidence. When put like that, it becomes clearer that what we've really described here is a defective brain. Let's call it "z-rational", and reserve the term 'rational' for brains that give rise to rational people -- people whose beliefs are in line with their total evidence.

Here are two implications:
(1) A z-rational brain can be expected to have more true z-beliefs (across all possible worlds).
(2) A rational brain can be expected to yield more true beliefs.

Fortunately, my brain is rational rather than z-rational. Hopefully yours is too (otherwise, you're a defective agent). One might try to argue that there's something "wrong" with a brain that isn't z-rational, but I don't think that'll work. For one thing, since you're really just describing a physical state it's not clear that brains or z-beliefs are even open to this sort of normative assessment. Norms apply primarily to people, and to our organs only derivatively. What a well-functioning agent really needs is a brain that will make them rational, not z-rational. As suggested above, a z-rational brain is defective from the standpoint of contributing to the functioning of the whole person (which is the relevant standpoint against which to assess brains). Further, when you stop to think about what it really means to have 'z-rational z-beliefs', you see that there's not really anything significant (worth caring about) there.

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Do Beliefs Exist?

Contrast two competing models of belief:

(A) [Full-blown existence.] Beliefs are something like sentences in the head, written in the language of thought, and physically located in one's "belief box" -- a special area of the brain, perhaps.

(B) Beliefs are more like useful fictions, patterns (Dennett compares them to centers of gravity), or projections that track certain dispositions. So they do not have any independent existence. Rather, S's believing that P is reducible to its being correct to ascribe or attribute this belief to S -- where the correctness conditions for this ascription make no further appeal to beliefs as such.

One may initially be tempted toward the first view on the grounds that it better captures the distinction between explicit and implicit beliefs. Explicit beliefs are literally there in your belief box, whereas one implicitly believes whatever can be easily inferred from one's explicit beliefs (for some appropriate standard of 'ease').

But this doesn't work at all, as Stalnaker points out in 'The Problem of Logical Omniscience, I'. What we want is a distinction between accessible and inaccessible information, but this is independent of the explicit/implicit distinction given to us by the belief box view. After all, just because some information is etched in our brains doesn't necessarily mean (given our search and computational limitations) that we will be able to find this information when we need it.

Imagine the phonebook man (I forget whose example this is), who has memorized the entire phonebook, ordered alphabetically. This way of storing the information means that, given a name as input, he can easily find the number that goes with it. But the reverse is not true: given a random phone number, Phonebook Man has little chance of finding the corresponding name in any reasonable period of time. So it would be misleading to say that he knows (or believes) that #555-5555 belongs to John Smith, even though this information is explicitly stored in his belief box.

On the other hand, he clearly does know the equivalent proposition that John Smith has phone number 555-5555. (He can look up John Smith and get the answer, no trouble.) The dispositions which underlie "belief" are thus relative to a question or probe. This seems to contradict our common-sense notion of belief.

How are we to resolve this puzzle?

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Content as Possible Worlds

One argument for a possible-worlds analysis of content is that it helps us make sense of partial understanding, as found for example in children and animals (Stalnaker, Inquiry, p.65):

The child who says that his daddy is a doctor understands what he says, and knows it is true, to some extent, because he can divide a certain, perhaps limited, range of possibilities in the right way and locate the actual world on the right side of the line he draws. As his understanding of what it is for Daddy to be a doctor grows, his capacity will extend to a larger set of alternative possibilities or, rather, the extension of this capacity will be the growth of his understanding.

A second issue is that one may have a belief 'by default', so to speak, taking something for granted even if one has never explicitly thought about it -- and sometimes only because one has never thought about it, as Stalnaker insightfully notes (p.69):

With riddles and puzzles as well as with many more serious intellectual problems, often all one needs to see that a certain solution is correct is to think of it--to see it as one of the possibilities.

Stalnaker accounts for this as follows (pp.68-9):

Attitudes are primarily attitudes to possible states of the world and not to the propositions that distinguish between those states. A belief state can be represented as a set of possible worlds. Individual beliefs are properties of such a belief state: to believe that P is for the proposition that P to be true in all the possible worlds in the belief state. If one conceives of beliefs in this way, they look like something negative: to believe that P is simply to be in a belief state which lacks any possible world in which P is false.

Can these two challenges be met just as well without appeal to possible worlds?

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Time-warped Experiences

This is interesting:

If the brain sped up when in danger, the researchers theorized, numbers on the perceptual chronometers would appear slow enough to read while volunteers fell. Instead, the scientists found that volunteers could not read the numbers at faster-than-normal speeds.

"We discovered that people are not like Neo in The Matrix, dodging bullets in slow-mo," Eagleman said.

Instead, such time warping seems to be a trick played by one's memory. When a person is scared, a brain area called the amygdala becomes more active, laying down an extra set of memories that go along with those normally taken care of by other parts of the brain. "In this way, frightening events are associated with richer and denser memories," Eagleman explained. "And the more memory you have of an event, the longer you believe it took."

Eagleman added this illusion "is related to the phenomenon that time seems to speed up as you grow older. When you're a child, you lay down rich memories for all your experiences; when you're older, you've seen it all before and lay down fewer memories. Therefore, when a child looks back at the end of a summer, it seems to have lasted forever; adults think it zoomed by."

Never mind physical (un)responsiveness; does your experience last longer when scared? Do you obtain more pleasure and pain by time seeming to you to pass slower? Does this give us additional reason to bring joy to children (and give less priority to aiding the elderly)?

I'm beginning to think that the way to count or measure an experience is not through its objective duration at all, but simply its richness of representational content (which may better reflect felt duration in any case). This may support my claim that multiple experiences matter less the less qualitatively different they are. Merely repeating the same old information over and over again does nothing to enrich the representation, after all.

Thoughts?

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Consciousness and Time

Inspired by the discussion at Pea Soup, let's distinguish:

(1) the external, physical duration of a phenomenal experience,
(2) the internal, felt duration of the experience, and
(3) the believed duration of the experience.

To illustrate the differences: Experience machine A gives you pleasant experiences for 100 years. Machine B (allegedly) gives you all the same experiences, feeling exactly the same from the inside, but packed into just a single real-time day. Machine C gives you one day of pleasure, and then simply implants in you the false belief that it felt like it lasted for 100 years.

A key question is whether dimension (2) is stable and independent of the others, i.e. whether Machines B and C are really distinct. But first, we must consider whether qualia (conscious experiences) are to be identified with brain states or their contents:

Our talk of conscious experience risks conflating two distinct objects: the qualities (properties) of the vehicular experience or representation itself, versus the qualities represented in the experience. It's plausible to think that we can access only the latter. For information to be available to us, it must be represented in our minds...

This includes experience itself: there may be facts about it of which we remain unaware. This is plausibly true of the temporal properties of our experiences, for instance. It seems to me that I experience A before experiencing B, but in actual fact all I have access to is my mental representation as of "A followed by B"... I don't really have a "mental eye" in my head to tell me what's going on in there, independently of what eventually enters into a conscious representation. Our introspective capabilities are hence severely limited.

Clearly, the brain states themselves last only a day in Machine B's case. But they represent 100 years' worth of happenings. How are we to describe this? Here are two options:

(i) What you experience is the brain state itself, and hence lasts for only a day; it's just that you're left with the false impression that it lasted longer than that. Machine B was misdescribed: in fact it is no different from C.

(ii) What you experience is the content as represented by the brain state, viz. 100 years. It is truly the same content/experience as given by Machine A; it's merely the physical bases of the experiences which differ, and that's nothing to care about.

I'm inclined towards (ii). But if experiences can so radically come apart from their underlying brain states, we may question whether Machine C is actually as deceptive as we'd assumed. If the implanted belief changes the contents represented in our phenomenal states, perhaps this actually gives us 100 years of experiences?

One reason for doubting this is reflection on the paucity of the representation. It's one thing to write a story which says "100 years passed", and quite another to fill out the details for 100 years' worth of fictional events. So, if we think of Machine A as taking a long time to impart rich informational content (lots of pleasure), and Machine C as taking a very short time to impart a very thin representation (very little pleasure), the question whether Machine B imparts a lot or only a little pleasure comes down to the richness of the representations it implants. Sound right?

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Expecting Immortality

"The experience of being dead should never be expected to any degree at all, because there is no such experience." So writes David Lewis in 'How Many Lives Has Schrodinger's Cat?' (p.17) But perhaps we can have negative expectations, in the sense of not positively expecting any further experiences.

What if I split, amoeba-style, into two future persons, one of whom is promptly shot? In general, I should split my expectations evenly between my future branches. Perhaps I should anticipate the experiences of each branch, separately. (I do not, of course, experience both lives together, in any mutually-accessible kind of way.) If one branch has no experiences at all - being killed before ever awakening, say - then all there is to anticipate is the other, surviving branch. But if it gets to experience a little before dying, then it would seem one allotment of my expectations should capture precisely this: to experience seeing the bullet approaching (or whatever), and then no more.

This is important because if the "no collapse" (or many-worlds) interpretation of Quantum Mechanics is correct, then we are actually splitting all the time. If you shoot me, there exists some (extremely low intensity) state in the superposition in which the bullet passes right through me. However often I die, there is always some version of me that survives. Should I expect, then, to be immortal? Lewis thinks so (p.19):

Suppose you're fairly sure that there are no collapses, and you're willing to run a risk in the service of truth. Go and wander about on a busy road, preferably a few minutes after closing time. When and if you find yourself still alive, you will have excellent evidence [for the no-collapse view]. If that's not yet enough to convince you, try the experiment a few more times.

What should you expect to happen?
(1) You miraculously emerge unscathed (perhaps the cars pass right through you by some quantum fluke).
(2) You get hit by a car, and then have no further experiences (due to being dead).
(3) You get hit by a car, but then miraculously survive (perhaps your crushed body reassembles itself by some quantum fluke).

On the no collapse view, all these outcomes occur, but (presumably) the second does so with much higher frequency or "intensity". Still, even if the overwhelmingly majority of superimposed states involve your getting hit by a car, you will always have some branch that survives this. So there are always further experiences to anticipate. Does this mean we should never anticipate ending up on a dead branch, i.e. one that has no further experiences?

It's not quite enough to ask whether we should expect to be immortal. On the no-collapse view, we are undoubtedly immortal, in the sense that we will always have some surviving branch. But we also die a lot, in that we have a great many terminating branches! So the real question is whether we should ever expect to die. Can our expectations be distributed over branches that contain no further experiences? Or are they restricted to the survivors only?

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Digital Minds

The old Scientism thread got a bit derailed by a side-discussion about the possibility of Strong Artificial Intelligence: the view that simulated minds could be real minds. To keep things tidy, I'm moving the comments here instead...

Arun: It is kind of obvious that no simulation by our computers - today or however advanced in the future - of QCD will produce quarks.

Why then is it philosophically acceptable to assume that the simulation of minds will produce minds?

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Me: suppose a mad scientist replaced some of your neurons with synthetic parts that were functionally identical. They would thus make no difference to the overall functioning of your brain. You would still have all the same thoughts, feelings, etc. Suppose we kept up the replacement, a few at a time, until your entire brain is synthetic. Do you still have a mind? It seems obvious that you would. One explanation for this is that what matters for mentality is the information-processing, rather than the physical substrate in which it occurs. In other words: the mind is software, not hardware.

(I should note, though, that this thesis of Strong AI is philosophically controversial. So it's not quite right to claim that it's "philosophically acceptable to assume" it. Arguments are certainly called for.)

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Arun: There are several fallacies here.

One is that little incremental changes can be extrapolated. It is entirely possible at some point in the process you've outlined, the mind degrades and finally vanishes.

Two is that even if "synthetically produced functionally identical parts" are used, that has something to do with software, simulation. I mean, I could replace all the parts in my Honda with imitation parts, and it still runs! Therefore "carness" resides not in the hardware?

Say, you replace neuron by neuron my neurons by stem-cell generated neurons (functionally identical synthetic parts). How does that prove that the mind is software?

If "mind is software" then a description of the algorithms it uses should not have to wait on hardware powerful enough to run those in reasonable time. Where are those? How far have we gotten with them?

This "mind is software" may be analogous to "DNA are character strings". Apart from encoding information however, DNA have beyond-the-reach of current simulation physical/chemical behavior that is essential to what it does. Its holding of information cannot be separated into "software" and "hardware".

Philosophy cannot answer these questions, it is a matter for **experimental** science.

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Jared: Those aren't fallacies; they're disagreements.

Anyway you're on the right track. The argument goes that "mindness" is in the functionality of the parts. So if you've synthetic parts that function just the same, then we'd expect the same results. On the level of an entire brain, we have neither the technology nor skill to make it work. But when it comes to restoring lost vision or hearing due to brain damage, there has been some success.

Philosophy is only technical in thinking, and so allows us to think of how our increasing technologies can be used (cf. Heidegger, Identity and Difference). Analogously, experimental science does not answer, it shows. Hence you need to have philosophy to do a good part of the explication.

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Arun: If the argument given is some kind of hand-waving plausibility argument, then yes, they're disagreements. If it an attempt at a logical presentation, they are fallacies.

I was merely going for hand-waving at the time, but it's an interesting issue, and one I know little about. Thoughts, anyone?

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Intuition Test: Self-Destruction

Suppose you will soon be subject to torture and degradation, such that you would prefer to die beforehand. Suicide is not allowed, but you are offered the opportunity to have all traces of your psychological self purged from your brain -- memories, character, talents, etc. Would that help? Would you fear the upcoming torture any less, perhaps believing that it would now be someone else rather than you who endures it?

How about if your psychological traces are completely transferred into the brain of another person, who goes on to live a happy, torture-free life?

Suppose now that the psychological transfer is compulsory, but beforehand you get to choose which body will be subsequently tortured. What would you choose?

(Cases from Bernard Williams, 'The Self and the Future'.)

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Are reasons in the head?

I'm thirsty - I desire that my thirst be quenched - so I drink some water. What is my reason for drinking the water? Is my desire itself the reason, or is the reason instead whatever qualities of the object inspire my desire, e.g. the water's thirst-quenching quality? Does it matter?

As a terminological point, it seems that a 'reason' is what answers a call for explanation. Why did/should I drink the water? "Because I wanted to" is not much of an answer. "Because it quenches thirst (and I was thirsty)" seems much better.

On the other hand, we want reasons to be the causes of our actions, and it seems more natural to say that our actions are caused by our beliefs and desires than by external qualities. But these are not really competing causal explanations. Features of the external world explain why we have the particular mental states we do. The world causes our behaviour by means of our beliefs and desires.

So there's a quick reason for favouring the view that reasons are things out in the world, rather than just in the head. I'm still not sure I grasp the significance of the debate, though. It's very much like the objects of perception debate (i.e. whether we perceive the external world or just internal sense-data). It all strikes me as mere wordplay and verbal confusion. The base facts are not in dispute: we have mental states that represent the external world. The only question seems to be how to talk about them sensibly. Or am I missing something?

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Indeterminate Identity and Abortion

In response to Edelman's claim that embryonic brain development "involves a dimension of randomness," Mark Vernon writes:

It is the suggestion that not everything is present in the zygote and that external forces subsequently act on the foetus to eventually create human individuality that leads to the conclusion that human life does not begin at conception or kick in at any one time.

I'm not convinced that Edelman's new biological theory adds anything new to the ethical debate. I mean, it's not exactly news that genetic determinism is false. And everyone else recognizes that "not everything is present in the zygote" -- Edelman's "stochastic processes" aside, how we develop as individuals will at least depend upon the cultural environment we're raised in, etc.

Perhaps the thought is that the potential variance here is so great that we're not talking about a single person developing in different ways; rather, the differences are so vast that they would amount to distinct people. That is, it's not just indeterminate how the fetus will develop; it's indeterminate who the fetus will grow to be. And, we might think, if the fetus' future identity is indeterminate, it cannot presently be identical to either person, and so presumably isn't a person at all.

But again, it's not clear how this argument depends on Edelman's theory, given that most of us already believe that a newborn has the potential to develop in very varied ways (within genetic constraints, just as Edelman grants).

In either case, it remains open to the pro-lifer to deny that even vast psychological differences entail that the possible future persons are numerically distinct. (They are simply alternative future states that the one person could grow into.) After all, the most coherent pro-lifers will be animalists about personal identity, in the sense that they identify human persons with human organisms -- and there's no real question that the latter come into existence at conception.

Am I missing something?

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Why do you think you're conscious?

If consciousness is epiphenomenal, then it plays no part in the actual causal explanation of why we believe ourselves to be conscious beings. That seems problematic, or so Peli Grietzer argues in an interesting email [quoted with permission]:

There's one aspect of the Zombie argument that I always felt was a tough bullet to bite, though, and I wonder if you have any thoughts: While various non-causal accounts of knowledge can handle the core-analytic kind of epistemological issues about phenomenal beliefs that arise from epiphenomenalism, I often fear that it leaves us with no decent scientific hypotheses as to the evolution of phenomenal beliefs, other than the amazing luck of humans evolving to believe they are not zombies coinciding with humans really not being zombies.

The obvious counter-argument is that it's no different than the "lucky coincidence" we assume when we reject brain-in-a-vat type sceptical scenarios despite lacking any good probabilistic reasons to do so, but there's a possibly critical difference. At least if our beliefs about the external world are true there is a natural story about how we came to have such beliefs and that story involves the external world, while if epiphenomenalism is true we still have no natural story about how we came to have beliefs about phenomenal consciousness, that [the story] involves phenomenal consciousness.

The technical version of the Zombie argument doesn't commit to epiphenomenalism in the same way the more vivid "zombie world" way of telling it does, though, so maybe it's more of a problem for epiphenomenalism than for the zombie argument.

Chalmers offers a neat answer: "The content of a conscious being's direct phenomenal beliefs is partly constituted by underlying phenomenal qualities. A zombie lacks those qualities, so it cannot have a phenomenal belief with the same content." For example, my concept of phenomenal 'redness' is grounded in the phenomenal quality of redness that I experience. My Zombie twin talks about 'redness', but in actual fact his concept is empty, ungrounded. So he doesn't mean what I do by the term.

On this account, phenomenal qualities (consciousness) can influence what we believe after all. Not causally, of course, but more directly, through constitution. The physical facts alone do not suffice to fix the intentional facts (i.e. what our thoughts are about). Phenomenal properties are part of what it is to have a phenomenal belief -- a belief that's truly "about" those very qualities. So, although a zombie would make all the same noises, their words and cognitive processes (arguably not really "thoughts") wouldn't have the meaning that ours do.

So much for particular phenomenal beliefs like 'this is red'. The original challenge was to explain our general self-attributions of consciousness. Can "phenomenal properties and the capacity to have them [still] play a crucial role in constituting its content", as Chalmers suggests? Seems plausible enough; there's nothing in the zombie's mind for his alleged concept of 'consciousness' to latch on to, for example. Surely it must be empty, again. The upshot: if we weren't conscious, we wouldn't believe it after all. Sure, we would still utter things like "of course I'm conscious!" -- but they would just be so much meaningless babble.

So, zombies are incapable of any positive conception of consciousness (and thus derivative concepts such as zombiehood). But I can think of a residual problem: what of the even more general claim that physicalism is false (i.e. a minimal physical duplicate of our world is not a full duplicate of our world)? This claim involves no phenomenal concepts, and so presumably can be thought without any need for phenomenal properties -- they aren't constitutive of this belief, at least. But that leaves us with only physical factors to explain why we disbelieve in physicalism! Odd, no?

The only way out that I can see is for the epiphenomenalist to adopt the strong position that consciousness grounds all genuine intentionality, so that zombies can't have any real concepts, beliefs, or mean anything at all. This way, even our non-phenomenal beliefs (e.g. about whether physicalism is true) are partly constituted by -- or otherwise depend upon -- phenomenal properties.

[Correction: an alternative option has been pointed out to me: the belief against physicalism inherits its epistemic warrant from the phenomenal beliefs from which it is inferred. In case of zombies, there is no such warrant to be transmitted.]

Consciousness explains why we have the beliefs we do, because without it, we wouldn't have any genuine beliefs at all.

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Dualist Explanations

Peter writes:

Chalmers posits that the non-physical mental properties parallel the information processing properties of the system. But if they parallel them perfectly, and thus explain the mind, why not just identify them? ... the dualist explanation posits something more than the materialist version of the same theory does: it must posit additional laws governing a new domain of mental stuff that makes it behave in this way and stick to the right sort of physical systems.

On the other hand, the (type B) materialist theory posits ad hoc 'strong necessities', which we have no independent reason to believe in. (Kripke's "necessary a posteriori" is no help.)

Consider the question: why aren't we non-conscious zombies, mere hunks of matter that exhibit complex behaviour without any "lights" on inside? The materialist answers that zombies are impossible; that consciousness is nothing above and beyond the complex arrangements of matter that our bodies (brains) comprise. But this strikes me as an unsatisfying explanation, that doesn't really do justice to the phenomena.

The dualist can do better. She may acknowledge the depth of the problem -- that consciousness is something new, something that goes beyond merely material properties. She can also acknowledge the modal fact that zombies (non-conscious physical duplicates of ourselves) are possible. So, rather than merely rebuffing the question "why aren't we zombies?" as empty or ill-formed, the dualist takes it seriously, and offers an answer:

The reason we're not zombies is because of the contingent natural laws that govern our universe. There are psycho-physical bridging laws, which ensure that matter gives rise to consciousness. (Note how intuitive this claim is: we think that consciousness emerges from the brain; not that it just is the brain!) The zombie world has no such bridging laws. Its laws are merely physical, so that brains and other matter causally interact without giving rise to genuine consciousness in addition. That's the difference.

Materialists can't explain this difference, because they don't take the zombie intuition seriously. Once the brain matter is there, they think that's all there is to consciousness -- there's nothing further to explain. Most of us think there is something still to be explained, and dualism can achieve this by positing bridging laws that cause 'mind' to emerge from 'matter'.

Even dualists can agree that in our world (i.e. given the actual laws of nature) complex brain states suffice for consciousness. The briding laws make zombies nomologically impossible. And that's all science is concerned with. As philosophers, though, we're interested in a broader sense of possibility, in which we can't just take the natural laws for granted. So, once our familiar psycho-physical bridging laws are taken away, we should ask: does matter alone suffice for consciousness? The zombie world demonstrates that the answer is no. Take away the bridging laws, and our physical stuff might no longer give rise to any conscious experiences.

In summary, it's worth emphasizing three points:

(1) Materialism - perhaps surprisingly - turns out to be theoretically extravagant, due to its modal ambitions. It posits 'strong necessities', which we have no independent reason to grant, and indeed goes against everything else we know in philosophy. Dualism is thus the more philosophically modest theory.

(2) Additional laws are worth positing, to explain why we're conscious rather than zombies. (The unsatisfying alternative is to merely dismiss the question.)

(3) Contrary to popular belief, dualism need not be in tension with science. It only diverges from materialism in its extra-nomological implications -- i.e. matters that concern philosophers, not scientists.

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Owning Dispositions (by degrees?)

The Milgram and Stanford Prison experiments may be taken to suggest that we are all disposed to act wickedly in certain situations. How should this fact be understood? Is there a little seed of evil lurking inside us, just waiting to get out? Or is it instead that some situations are so extraordinary that they would cause us to behave abnormally, "out of character" with our "true self"? Is this a real distinction? If so, what is its basis, and how do we tell whether any given counterfactual has import for one's "true character"? (I asked a similar question here.)

Another example may help bring out the problem. Suppose a mad scientist could rewire my brain so that I became a crazed serial killer. It seems absurd to say that I already have the disposition to become a crazed serial killer "if rewired". The antecedent condition is one that changes who I am - my character and dispositions - so the counterfactual doesn't really reflect at all on my actual character and dispositions. (Cf. the conditional fallacy.)

I guess the key issue here is whether my current state contains the "causal basis" of my counterfactual behaviour, or whether this is something that's newly introduced by the antecedent condition. Drastic neural rewiring alters the causal basis of my behaviour. But all thought and experience involves some degree of neural rewiring - our brain changes, that's how we learn! So how can we draw any strict line here, between changes that merely draw on our existing dispositions, and changes that introduce whole new ones? Our terms suggest a difference in kind, when the neurobiology may merely differ in degree.

The above discussion seems lacking in conceptual clarity. There must be a better way to understand these issues. Any suggestions? (Quick thought: perhaps dispositions should be understood more exclusively as general tendencies, manifest in a much broader range of behaviours. Then we may discard the above cases as too isolated and specific to justify invoking 'dispositions'.)

Similar issues arise for dispositional beliefs. Peter distinguishes between dormant actual beliefs ("my name is Peter") and merely derivable beliefs ("25 - 11 = 14"). He suggests that the difference consists in whether the proposition is "directly integrated into the person’s mental operations", and so "immediately available when needed". He adds:

It is natural to say that plain beliefs are always in mind, although usually unconscious, but derived beliefs are not usually present in any way, except when they are consciously derived from plain beliefs.

This sounds like the above distinction between owned (internal) and disowned (external) dispositions; those that are already present in the agent, and those that aren't (but would be given the right stimulus). But aren't integration and availability likewise matters of degree?

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Fun with Neural Grounding

It's amazing what brains can do (if we assume that they "ground" every subject that we think about):

Because Homo sapiens is the only species to construct complex moral systems, morality has to be grounded in some distinctive property of the human brain

Reader challenge: On the assumption that this is a valid argument form, what's the most outlandish reductio you can come up with? (E.g. "Because Homo sapiens is the only species to construct complex electrical systems, electricity has to be grounded in some distinctive property of the human brain." Zap!)

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Fission and Identity

Johnny-Dee quotes Swinburne's take on fission:

Reflection on this thought experiment shows that, however much we know about what has happened to my brain—we may know exactly what has happened to every atom in it—and to every other material part of me, we do not necessarily know what has happened to me. From that it follows that there must be more to me than the matter of which my body and brain are made, a further essential immaterial part whose continuing in existence makes the brain (and so the body) to which it is connected my brain (and body), and to this something I give the traditional name of ’soul’. I am my soul plus whatever brain (and body) it is connected to. Normally my soul goes where my brain goes, but in unusual circumstances (such as when my brain is split) it is uncertain where it goes.

I prefer Parfit's solution, which is to deny that there is any further fact here to know. The physical and psychological facts exhaust the facts. Once those are all specified, there is nothing left to know about the world. It would seem strange to posit two possibilities, alike in every objective and subjective respect, yet somehow differing in virtue of the "identity facts". For what would those consist in, and how could we ever grasp them? Our commonsense concept of identity tracks a familiar kind of continuity, but we have no reason to think there's anything further underlying it.

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Can something be bigger than everything?

Ah, fractals... the video eventually zooms in so far that the entire expanse of the image you started with would now be larger than the known universe. (Kind of like powers of ten, but more purely mathematical, and so even "bigger"!) Pretty cool.

There's some fun discussion at Metafilter [hat-tip: Dillon] about how it is that anything could be larger than the entire universe. In response, one comment offered a nice analogy to highlight the merely virtual nature of the fractal space: "If you play Doom 3, the environment is larger than your house. How can that be when the computer is INSIDE your house?" Clearly, the universe can contain representations as of something bigger than the universe actually is, but the representations themselves -- bits in a computer -- have a more modest reality.

Is it our natural tendency to confuse the ontological status of representing and represented things that makes the fractal video so awe-inspiring? After all, in itself the sequence of images seems nothing all that special. But if you interpret them in such a way as to feel almost drawn into contradiction, and led to ponder the mysteries of the universe, that's something else entirely. Then again, perhaps the provided hint of incoherence plays no crucial role here -- it may be enough simply to vividly represent astronomical scales, and let the dwarfing effect run its own course. What do you think?

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