From Sensor Variables to Phenomenal Facts

I wrote this short piece for a special issue of the Journal of Consciousness Studies on Chalmers's "The Meta-Problem of Consciousness" (2018). Much of my paper rehashes ideas from section 5 of my "Imaginary Foundations" paper, but here I try to present these ideas more simply and directly, without the Bayesian background.

The central claim I try to defend is that the hard problem of consciousness arises from a particular method by which our brain processes sensory input. Agents whose brain uses that method can be expected to be puzzled about phenomenal consciousness, even if they live in a purely physical world. The story is meant to answer the "meta-problem" of what gives rise to our puzzlement about consciousness, but it is also meant to dissolve the first-order problem: once we understand the source of the puzzlement, we should no longer be puzzled.

One issue I didn't explicitly address in "Imaginary Foundations", but do briefly address in the new paper, is what first-order theory of consciousness actually emerges from my proposal: Are there phenomenal properties? Are they reducible to physical properties? Does Mary learn something new? Are zombies possible? Are we zombies?

My answer is complicated, and to some extent echoes what non-cognitivists say about moral properties. In a sense, I'm an eliminativist or illusionist about phenomenal properties: there are no such things out there in objective reality. However, on the proposal I outline, our credences in hypotheses about phenomenal properties ("imaginary propositions") do not serve a straightforwardly representational function. Their purpose is to allow for an efficient and context-sensitive update of our genuine beliefs about the world. If you give credence zero to all imaginary propositions, your update system is broken. You shouldn't do that, even if you know that there is nothing in the world that makes any imaginary proposition true. In a nutshell, it's OK to have beliefs about phenomenal properties, and to talk about them, even though neither the beliefs nor the assertions track anything in metaphysical reality.

I had a strict limit of 4000 words, so I couldn't spell out any details. As a result, I'm still not sure what some of the details should look like. I also didn't have space to connect what I'm saying to the various proposals discussed by Chalmers, let alone to the rest of the literature. In many ways, my ideas are closely related to lots of other ideas that have been put forward. I'm not even sure if I'm saying something new at all, as opposed to saying something old in a new way.


# on 12 June 2019, 06:48

I read 'Imaginary Foundations' when you posted it and have been excited about your explanation ever since. It seems very plausible to me, and I also just find its explanatoriness remarkable - it really seems to be an unexpectedly straight answer to 'What would an explanation even look like?'.

Clearly there's room for more work and different views about the upshot of the explanation. I've got some thoughts and questions, split into three parts:


If you think of dualism as positing a kind of nonphysical external world, or nonphysical properties of the external world, then it does seem that your explanation pushes one away from dualism.

But the questions about properties, facts, knowledge, or (genuine) truth seem more open.

It's clear that with this group of questions you lean towards a subtle kind of eliminativism. But someone could accept your explanation of the seeming and instead prefer reductionism or primitivism.

The kind of reductionism you consider in this new piece seems like not the best kind. I agree that thinking of the content of a phenomenal sentence Q as being the same as some sentence about electrochemical patterns is unattractive for the reason you give (ideally rational and competent speakers should be able to tell when two sentences have the same content). But I wonder if a functionalist form of reductionism may be a good option here. 'There is a chair here' isn't a priori equivalent to some statement about chair-building materials, and yet can in some sense be true in virtue of physical facts. Why not say something similar about phenomenal truths?

Or why not just allow that there are phenomenal facts, and that you've explained why we know and talk about them, without attempting a reduction? (I guess what I really suspect here is that one should be a reductionist in connection with certain precisifications of 'in virtue of' or 'represents' and a primitivist in connection with others.)


You seem to favour a view on which statements whose truth or falsity doesn't turn on the way the physical world is are not 'genuinely true' or 'genuinely false'. But I wonder how this apparent preference of yours fits with mathematical truth.

I've already asked about a functionalist approach, where in some sense phenomenal statements *do* turn on the physical world, only in the way that table-talk does rather than in the way that particle-talk does.

But, that aside, you might think (as I do) that mathematical truths are as deserving of being called 'genuine' truths as any, and that they nevertheless don't impose conditions on the physical world. On that view, should we just forget about having a notion of 'genuine' truth which phenomenal truths don't enjoy? Or should we look for other criteria that rule in both mathematical and physical truths and rule out the phenomenal?


The talk of 'metaphysical reality' made me wonder what people who think that such a notion should be problematized should make of your explanation. It'd be a shame if your message was only palatable to card-carrying metaphysicians who are happy to talk like this. For my part I'm suspicious that talking about 'metaphysical reality' is a dubious kind of having-it-both-ways, an unstable mixture of the idea of "stuff going on out there in the world" and the apparently broader categories of properties, truth, facts, knowledge, etc. The same kind of worry I get when thinking about Platonism about mathematics.

# on 13 June 2019, 12:27

Hi Tristan,

thanks, great comments! You're right that there are probably different ways to interpret the picture I've put forward. My initial reaction to the points you raise:

- On the reductionist account: I'm inclined to think that whenever A is true in virtue of B (in some relevant sense), then one could in principle deduce A from B. On that assumption, phenomenal/imaginary propositions won't be reducible to physical propositions. I also like coarse-grained accounts of content. So I'd like to know which set of worlds "I am feeling pain" is supposed to express, on the reductionist proposal, and I don't see any plausible answer. But I'm obviously invoking very controversial assumptions here. Would be interesting to see to what extent they can be dropped.

- On the primitivist account: I'm happy to say that in some sense, phenomenal facts are primitive. But that will be a "quasi-realist" way of speaking, since there's another sense in which I want to say that reality is completely described by physics, so that all primitive (positive) facts are physical facts.

- You're right that some genuine truths don't turn on the way the physical world is. But they don't turn on anything at all: they're non-contingent. Phenomenal propositions seem to be contingent. On the picture I like, something is a genuine truth if (roughly) an ideal reasoner could a priori infer it from the complete description of physical reality. Mathematical truths are in because they can be a priori inferred from no assumptions at all.

- Not sure I follow the worry about "metaphysical reality". Perhaps it's just an unfortunate label. All I'm assuming is that there is an objective world that physics and other sciences aim at describing. I want to defend the view that one can in principle describe that world completely in physical terms, without invoking phenomenal notions.

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