Trope theory and merely numerical differences in pleasures

Suppose I eat a chocolate bar and this causes me to have a trope of pleasure. Given assentiality of origins, if I had eaten a numerically different chocolate bar that caused the same pleasure, I would have had had a numerically different trope of pleasure.

Now, imagine that I eat a chocolate bar in my right hand and it causes me to have a trope of pleasure R, and immediately as I have finished eating that one chocolate bar, I switch to eating the chocolate bar in my left hand, which gives me an exactly similar trope of pleasure, L, with no temporal gap. Nonetheless, by essentiality of origins, trope L is numerically distinct from trope R.

To some (perhaps Armstrong) this will seem absurd. But I think it’s exactly right. In fact, I think it may even an argument for trope theory. For it seems pretty plausible that as I switch chocolate bars, something changes in me: I go from one pleasure to another exactly like it. But on heavy-weight Platonism, there is no change: I instantiated pleasure and now I instantiate pleasure. On non-trope nominalism, likewise there is no change. It’s trope theory that gives us the change here.

Epiphenomenalism and epistemic changes wrought by experiences

Epiphenomenalists think that there are non-physical qualia that are causally inert: all causes are physical. The main reason epiphenomenalists have for supposing the existence of non-physical qualia is Jackson’s famous black-and-white Mary thought experiment. Mary is brought up in a black-and-white room, learns all physical truths about the world, and one day is shown a red tomato. It is alleged that before she is shown the red tomato, Mary doesn’t know what it’s like to see red, but of course once she’s been shown it, she knows it, like we all do. Since she didn’t know it before and yet knew all physical truths, it follows that the the fact about what it’s like to see red goes beyond physical reality.

Now, let’s fill out the thought experiment. After she has been shown the tomato, Mary is put back in the black-and-white room, and never again has any experiences of red. It seems clear that at this point, Mary still knows what it’s like to see red, just as we know what it’s like to see red when we are not occurrently experiencing red.

So, what happened to Mary must have changed her in some way: she now knows what it’s like to see red, but didn’t know it before.

But given epiphenomenalism, this change is problematic. For it seems that it isn’t the quale of red that has changed Mary, since qualia are causally inert. It seems that Mary was changed by the physical correlate of the experience of red, rather than by the experience of red itself.

However, if this is right, then imagine Mary’s twin Martha, who has almost exactly the same things happen to her. Martha is brought up in an exactly similar black-and-white room, then shown a red tomato, and then brought back to the room. There is, however, one curious difference. During the short period of time during which Martha is presented the tomato, a supernatural being turns her into a redness-zombie, by preventing her from having any phenomenal experiences of red, without affecting any of her physical states. Since on epiphenomenalism, the experience of red is causally inert, this makes no difference to Martha’s future intrinsic states. In particular, Martha thinks she knows what it’s like to see red, just as Mary does.

But it seems that epiphenomenalist who relies on the Mary thought experiment for the existence of qualia cannot afford to say that Martha knows what it’s like to see red. For Martha is a redness-zombie in the one crucial moment of her life when there is something red for her to see. If Martha can know what it’s like to see red, so can a permanent redness-zombie. And that doesn’t seem to fit with the intuitions of those who find the Mary thought experiment compelling.

The epiphenomenalist will thus say that after the tomato incident, Mary and Martha are exactly alike physically, and both think they know what it’s like to see red, but only Mary knows. Does Martha have a true opinion, but not knowledge? That can’t be right either, since someone who has true opinion but not knowledge can gain knowledge by being told by an epistemic authority that their opinion is true, and surely mere words won’t turn Martha into a knower of what it’s like to see red. The alleged difference between Martha and Mary is very puzzling.

There is a possible story the epiphenomenalist can tell. The epiphenomenalist could say that the physical correlates of her experience of red have caused Mary to have the ability to imagine red and have visual memories of red, and this ability makes Mary into a knower of what it’s like to see red. Since Martha had the same physical correlate, she also has the same imaginative and memory abilities, and hence knows what it’s like to see red. It may initially seem threatening to the epiphenomenalist that Martha has gained the knowledge of what it’s like to see red without an experience of red, but if she has gained this by becoming able to self-induce such experiences, this is perhaps not threatening.

But this story has one serious problem: it doesn’t work if both Mary and Martha are total color aphantasiacs, unable to imagine or visually imagine colors (either at all, or other than black and white). Could the epiphenomenalist say that a color aphantasiac doesn’t know what it’s like to see red when not having an occurrent experience of red? That could be claimed, but it seems implausible. (And it goes against The Shadow’s first-person testimony that they are an aphantasiac and yet know what it’s like to see green.)

Perhaps the epiphenomenalist’s best move would be to say that no one knows what it’s like to see red when not having an occurrent experience of red. But this does not seem intuitive. Moreover, the physicalist could then respond that the epiphenomenalist is confusing knowledge with occurrent experience.

All in all, I think it’s really hard for the epiphenomenalist to explain how Mary’s knowledge changed as a result of the tomato incident.

Knowing what it's like to see green

You know what it’s like to see green. Close your eyes. Do you still know what it’s like to see green?

I think so.

Maybe you got lucky and saw some green patches while closing your eyes. But I am not assuming that happened. Even if you saw no green patches, you knew what it is like to see green.

Philosophers who are really taken with qualia sometimes say that:

1. Our knowledge of what it is like to see green could only be conferred on me by having an experience of green.

But if I have the knowledge of what it is like to see green when I am not experiencing green, then that can’t be right. For whatever state I am in when not experiencing green but knowing what it’s like to see green is a state that God could gift me with without ever giving me an experience of green. (One might worry that then it wouldn’t be knowledge, but something like true belief. But God could testify to the accuracy of my state, and that would make it knowledge.)

Perhaps, however, we can say this. When your eyes are closed and you see no green patches, you know what it’s like to see green in virtue of having the ability to visualize green, an ability that generates experiences of green. If so, we might weaken (1) to:

2. Our knowledge of what it is like to see green could only be conferred on me by having an experience of green or an ability to generate such an experience at will by visual imagination.

We still have a conceptual connection between knowledge of the qualia and experience of the qualia then.

But I think (2) is still questionable. First, it seems to equivocate on “knowledge”. Knowledge grounded in abilities seems to be knowledge-how, and that’s not what the advocates of qualia are talking about.

Second, suppose you’ve grown up never seeing green. And then God gives you an ability to generate an experience of green at will by visual imagination: if you “squint your imagination” thus-and-so, you will see a green patch. But you’ve never so squinted yet. It seems odd to say you know what it’s like to see green.

Third, our powers of visual imagination vary significantly. Surely I know what it’s like to see paradigm instances of green, say the green of a lawn in an area what water is plentiful. If I try to imagine a green patch, if I get lucky, my mind’s eye presents to me a patch of something dim, muddy and greenish, or maybe a lime green flash. I can’t imagine a paradigm instance of green. And yet surely, I know what it’s like to see paradigm instances of green. It seems implausible to think that when my eyes are closed my knowledge of what it’s like to see green (and even paradigm green) is grounded in my ability to visualize these dim non-paradigm instances.

It seems to me that what the qualia fanatic should say is that:

3. We only know what it’s like to see green when we are experiencing green.

But I think that weakens arguments from qualia against materialism because (3) is more than a little counterintuitive.

A weaker epiphenomenalism

A prominent objection to epiphenomenalist theories of qualia, on which qualia have no causal efficacy, is that then we have no way of knowing that we had a quale of red. For a redness-zombie, who has no quale of red, would have the very same “I am having a quale of red” thought as me, since my “I am having a quale of red” thought is not caused by the quale of red.

There is a slight tweak to epiphenomanalism that escapes this objection, and the tweaked theory seems worth some consideration. Instead of saying that qualia have no causal efficacy, on our weaker epiphenomenalism we say that qualia have no physical effects. We can then say that my “I am having a quale of red” thought is composed of two components: one of these components is a physical state ϕ₂ and the other is a quale q₂ constituting the subjective feeling of thinking that I am having a quale of red. After all, conscious thoughts plainly have qualia, just as perceptions do, if there are qualia at all. We can now say that the physical state ϕ₂ is caused by the physical correlate ϕ₁ of the quale of red, while the quale q₂ is wholly or partly caused by the quale q₁ of red.

As a result, my conscious thought “I am having a quale of red” would not have occurred if I lacked the quale of red. All that would have occurred would be the physical part of the conscious thought, ϕ₂, which physical part is what is responsible for further physical effects (such as my saying that I am having a quale of red).

If this is right, then the induced skepticism about qualia will be limited to skepticism with respect to unconscious thoughts about qualia. And that’s not much of a skepticism!

Knowledge of qualia

Suppose epiphenomenalism is true about qualia, so qualia are nonphysical properties that have no causal impact on anything. Let w₀ be the actual world and let w₁ be a world which is exactly like the actual world, except that (a) there are no qualia (so it’s a zombie world) and (b) instead of qualia, there are causally inefficacious nonphysical properties that have a logical structure isomorphic to the qualia of our world, and that occur in the corresponding places in the spatiotemporal and causal nexuses. Call these properties “epis”.

The following seems pretty obvious to me:

1. In w₁, nobody knows about the epis.

But the relationship of our beliefs about qualia to the qualia themselves seems to be exactly like the relationship of the denizens of w₁ to the epis. In particular, neither are any of their beliefs caused by the obtaining of epis, nor are any of our beliefs caused by the obtaining of qualia, since both are epiphenomenal. So, plausibly:

2. If in w₁, nobody knows about the epis, then in w₀, nobody knows about the qualia.

Conclusion:

3. Nobody knows about the qualia.

But of course we do! So epiphenomenalism is false.

Do you and I see colors the same way?

Suppose that Mary and Twin Mary live almost exactly duplicate lives in an almost black-and-white environment. The exception to the duplication of the lives and to the black-and-white character of the environment is that on their 18th birthday, each sees a colored square for a minute. Mary sees a green square and Twin Mary sees a blue square.

Intuitively, Mary and Twin Mary have different phenomenal experiences on their 18th birthday. But while I acknowledge that this is intuitive, I think it is also deniable. We might suppose that they simply have a “new color” experience on their 18th birthday, but it is qualitatively the same “new color” experience. Maybe what determines the qualitative character of a color experience is not the physical color that is perceived, but the relationship of this color to the whole body of our experience. Given that green and blue have the same relationship to the other (i.e., monochromatic) color experiences of Mary and Twin-Mary, it may be that they appear the same way.

If this kind of relationalism is correct, then it is very likely that when you and I look at the same blue sky, our experiences are qualitatively different. Your phenomenal experience is defined by its position in the network of your experiences and mine is defined by its position in the network of my experiences. Since these networks are different, the experiences are different. Somehow I find this idea somewhat plausible. It is even more plausible some experiences other than colors. Take tastes and smells. It’s not unlikely that fried cabbage tastes differently to me because in the network of my experiences it has connections to experiences of my grandmother’s cooking that it does not have in your network.

Such a relationalism could help explain the wide variation in sensory preferences. We normally suppose that people disagree on which tastes they like and dislike. But what if they don’t? What if instead the phenomenal tastes are different? What if banana muffins, which I dislike, taste differently to me than they do to most people, because they have a place in a different network of experiences, and if banana muffins tasted to me like they do to you, I would like them just as much?

In his original Mary thought experiment, Jackson says that monochrome Mary upon experiencing red for the first time learns what experience other people were having when they saw a red tomato. If the above hypothesis is right, she doesn’t learn that at all. Other people’s experiences of a red tomato would be very different from Mary’s, because Mary’s monochrome upbringing would place the red tomato in a very different network of experiences from that which it has in other people’s networks of experiences. (I don’t think this does much damage to the thought experiment as an argument against physicalism. Mary still seems to learn something—what it is to have an experience occupying such-and-such a spot in her network of experiences.)

More fun with monochrome Mary

Here’s a fun variant of the black-and-white Mary thought experiment. Mary has been brought up in a black-and-white environment, but knows all the microphysics of the universe from a big book. One day she sees a flash of green light. She gains the phenomenal concept α that applies to the specific look of that flash. But does Mary know what green light looks like?

You might think she knows because her microphysics book will inform her that on such-and-such a day, there was a flash of green light in her room, and so she now knows that a flash of green light has appearance α. But that is not quite right. A microphysics book will not tell Mary that there was a flash of green light in her room. It will tell her that there was a flash of green light in a room with such-and-such physical properties. Whether she can deduce from these properties and her observations that this was her room depends on what the rest of the universe is like. If the universe contains Twin Mary who lives in a room with exactly the same monochromatically observable properties as Mary’s room, but where at the analogous time there is a flash of blue light, then Mary will have no way to resolve the question of whether she is the woman in the room with the green flash or in the room with the blue flash. And so, even though Mary knows all the microphysical facts about the world, Mary doesn’t know whether it is a green flash or a blue flash that has appearance α.

This version of the Mary thought experiment seems to show that there is something very clear, specific and even verbalizable (since Mary can stipulate a term in her language to express the concept α, though if Wittgenstein is right about the private language argument, we might require a community of people living in Mary’s predicament) that can remain unknown even when one knows all the microphysical facts and has all the relevant concepts and has had the relevant experiences: Whether it is green or blue light that has appearance α?

This seems to do quite a bit of damage to physicalism, by showing that the correlation between phenomenal appearances and physical facts is a fact about the world going beyond microphysics.

But now suppose Joan lives on Earth in a universe which contains both Earth and Twin Earth. The denizens of both planets are prescientific, and at their prescientific level of observation, everything is exactly alike between Earth and Twin Earth. Finer-grained observation, however, would reveal that Earth’s predominant surface liquid is H₂O while Twin Earth’s is XYZ, but currently there is no difference. Now, Joan reads a book that tells her in full detail all the microphysical structure of the universe.

Having read the book, Joan wonders: Is water H₂O or is it XYZ? Just by reading the book, she can’t know! The reason she doesn’t know it is because her prescientific observations combined with the contents of the book are insufficient to inform her whether she lives on Earth or on Twin Earth, whether she is Joan or Twin Joan, and hence are insufficient to inform her whether the liquid she refers to as “water” is H₂O or XYZ.

But surely this shouldn’t make us abandon physicalism about water!

Now Joan and Twin Joan both have concepts that they verbalize as “water”. The difference between these concepts is entirely external to Joan and Twin Joan—the difference comes entirely from the identity of the liquid interaction with which gave rise to the respective concepts. The concepts are essentially ostensive in their differences. In other words, Joan’s ignorance of whether water is H₂O or XYZ is basically an ignorance of self-locating fact: is she in the vicinity of H₂O or in the vicinity of XYZ.

Is this true for Mary and Twin Mary? Can we say that Mary’s ignorance of whether it is a green or a blue flash that has appearance α is essentially an ignorance of self-locating facts? Can we say that the difference between Mary’s phenomenal concept formed from the green flash and Twin Mary’s phenomenal concept formed from the blue flash is an external difference?

Intuitively, the answer to both questions is negative. But the point is not all that clear to me. It could turn out that both Mary and Twin Mary have a purely comparative recognitive concept of “the same phenomenal appearance as that flash”, together with an ability to recognize that similarity, and with the two concepts being internally exactly alike. If so, then the argument is unconvincing as an argument against physicalism.

Physicalism and "pain"

Assuming physicalism, plausibly there are a number of fairly natural physical properties that occur when and only when I am having a phenomenal experience of pain, all of which stand in the same causal relations to other relevant properties of me. For instance:

1. having a brain in neural state N

2. having a human brain in neural state N

3. having a primate brain in neural state N

4. having a mammalian brain in neural state N

5. having a brain in functional state F

6. having a human brain in functional state F

7. having a primate brain in functional state F

8. having a mammalian brain in functional state F

9. having a central control system in functional state F.

Suppose that one of these is in fact identical with the phenomenal experience of pain. But which one? The question is substantive and ethically important. If, for instance, the answer is (c), then cats and computers in principle couldn’t feel pain but chimpanzees could. If the answer is (i), then cats and computers and chimpanzees could all feel pain.

It is plausible on physicalism (e.g., Loar’s version) that my concept of pain refers to a physical property by ostension—I am ostending to the state that occurs in me in all and only the cases where I am in pain, and which has the right kind of causal connection to my pain behaviors. But there are many such states, as we saw above.

We might try to break the tie by saying that by reference magnetism I am ostending to the simplest physical state that has the above role, and the simplest one is probably (i). I don’t think this is plausible. Assuming naturalism, when multiple properties of a comparable degree of naturalness play a given role, ostension via the role is likely to be ambiguous, with ambiguity needing to be broken by a speaker or community decision. At some point in the history of biology, we had to decide whether to use “fish” at a coarse-grained functional level and include dolphins and whales as fish, or at a finer-grained level and get the current biological concept. One option might be a little more natural than the other, but neither is decisively more natural (any fish concept that has a close connection to ordinary language is going to have to be paraphyletic), and so a decision was needed. And even if (i) is somewhat simpler than (a)–(h), it is not decisively more natural.

This yields an interesting variant of the knowledge argument against physicalism.

1. If “pain” refers to a physical property, it is a “merely semantic” question, one settled by linguistic decision, whether “pain” could apply to an appropriately programmed computer.

2. It is not a “merely semantic” question, one settled by languistic decision, whether “pain” could apply to an appropriately programmed computer.

3. Thus, “pain” does not refer to a physical property.

Something Mary doesn't know

Here is something our old friend Mary, raised in a black and white world, cannot know simply by knowing all of physics:

1. What are the necessary and sufficient physical conditions for two individuals to be in exactly the same phenomenal state?

Of course, her being raised in a black and white world is a red herring. I think nobody can know the answer to (2) simply by knowing all of physics.

Some remarks:

• Knowledge of the answer to (1) is clearly factual descriptive knowledge. So responses to the standard knowledge argument for dualism that distinguish kinds of knowledge have no effect here.

• The answer to (1) could presumably be formulated entirely in the language of physics.

• Question (1) has a presupposition, namely that there are necessary and sufficient physical conditions, but the physicalist can’t deny that.

• A sufficient conditions is easy given physicalism: the individuals have the exact same physical state.

• Dennettian RoboMary-style simulation does not solve the question. One might hope that if you rewrite your software, you can check if you have the same qualia before and after the rewrite. But the problem is that you can only really do exact comparisons of qualia that you see in a unified way, and there is insufficient unification of your state across the software rewrite.

The hand and the moon

Suppose Alice tells me: “My right hand is identical with the moon.”

My first reaction will be to suppose that Alice is employing some sort of metaphor, or is using language in some unusual way. But suppose that further conversation rules out any such hypotheses. Alice is not claiming some deep pantheistic connection between things in the universe, or holding that her hand accompanies her like the moon accompanies the earth, or anything like that. She is literally claiming of the object that the typical person will identify as “Alice’s hand” that it is the very same entity as the typical person will identify as “the moon”.

I think I would be a little stymied at this point. Suppose I expressed this puzzlement to Alice, and she said: “An oracle told me that over the next decade my hand will swell to enormous proportions, and will turn hard and rocky, the exact size and shape of the moon. Then aliens will amputate the hand, put it in a giant time machine, send it back 4.5 billion years, so that it will orbit the earth for billions of years. So, you see, my hand literally is the moon.”

If Alice isn’t pulling my leg, she is insane to think this. But now I can make some sense of her communication. Yes, she really is using words in the ordinary and literal sense.

Now, to some dualist philosophers the claim that a mental state of feeling sourness is an electrochemical process in the brain is about as weird as the claim that Alice’s hand is the moon. I’ve never found this “obvious difference” argument very plausible, despite being a dualist. Thinking through my Alice story makes me a little more sympathetic to the idea that there is something incredible about the mental-physical identity claim. But I think there is an obvious difference between the hand = moon and quale = brain-state claims. The hand and the moon obviously have incompatible properties: the colors are different, the shapes are different, etc. Some sort of an explanation is needed how that can happen despite identity—say, time-travel.

The analogue would be something like this: the quale doesn’t have a shape, while the brain process does. But it doesn’t seem at all clear to me that the quale positively doesn’t have a shape. It’s just that it is not the case that it positively seems to have a shape. Imagine that qualia turned out to be nonphysical but spatially extended entities spread through regions of the brain, kind of like a ghost is a nonphysical but spatially extended entity. There is nothing obvious about the falsity of this hypothesis. And on this hypothesis, qualia would have shape.

To be honest, I suspect that even if qualia don’t have a shape, God could give them the additional properties (say, the right relation to points of space) that would give them shape.

Motivating panpsychism

There is something attractive about an ontology where all the properties are powers, but it seems objectionable.

First, a power is partly defined by the properties it can produce. But if these in turn are powers, then we have a vicious regress or circularity.

At the same time, mental properties do not seem to be purely powers: they seem to have a categorical qualitative character that is not captured by the power to produce something else.

What is attractive about a pure powers ontology is the conceptual simplicity, and the fact that categorical properties seem really mysterious.

There is, however, a modification we can make to a pure powers ontology that gets us out of the problem. There are two kinds of properties: powers and qualia. The mysteriousness objection does not apply to qualia, because we experience them. On this ontology, powers bottom out in the ability to produce qualia.

For this to avoid implausible anthropocentrism, we need panpsychism—only then will there be enough qualia outside of living things for the powers of fundamental physics to bottom out in. So we have an interesting motivation for panpsychism: it yields an attractive ontology for reasons that have nothing to do with the usual concerns in the philosophy of mind.

It’s worth noting that this ontology is similar to Leibniz’s. Leibniz had two kinds of properties: appetitions and perceptions. The appetitions are (deterministic) powers. Perceptions are similar to qualia, but not quite the same, because (a) perceptions need not be conscious, and (b) perceptions are always representational. Unfortunately, the representational aspect leads to a regress or circularity problem, much as the power powers ontology did, since representationality will define a perception in terms of other appetitions and perceptions.

Forwards causal closure and dualist theories of perception

A standard dualist theory of perception goes like this:

1. You sense stuff physically, the data goes to the brain, the brain processes the data, and out of the processed data produces qualia.

There is a lot of discussion of the “causal closure” of the physical. What people generally mean by this is that the physical is causally backwards-closed: the cause of a physical thing is itself physical. This is a controversial doctrine, not least because it seems to imply that some physical things are uncaused. But what doesn’t get discussed much is a more plausible doctrine we might call the forwards causal closure of the physical: physical causes only have physical effects. Forwards causal closure of the physical is, I think, a very plausible candidate for a conceptual truth. The physical isn’t spooky—and it is spooky to have the power of producing something spooky. (One could leave this at this conceptual argument, or one could add the scholastic maxim that one cannot cause what one does not in some sense have.)

By forwards closure, on the standard dualist theory, the brain is not a physical thing. This is a problem. It is supposed to be one of the advantages of the standard dualist theory that it is compatible with property dualism on which people are physical but have non-physical properties. But if the brain is not physical, there is no hope for people to be physical! Personally, I don’t mind losing property dualism, but it sure sounds absurd to hold that the brain is not physical.

Recently, I have been thinking about a non-causal dualist theory that goes like this:

2. You sense stuff physically, the data goes to the brain, the brain processes the data, and the soul “observes” the brain’s processed data. (Or, perhaps more precisely, the person "feels" the neural data through the soul.)

To expand on this, what makes one feel pain is not the existence of a pain quale, but a sui generis “observation” relation between the soul and the brain’s processed data. This observation relation is not caused by the data, but takes place whether there is data there or not (if there isn’t, we have a perceptual blank slate). The soul is not changed intrinsically by the data: the “observation” of a particular datum—say, a datum representing a sharp pain in a toe—is an extrinsic feature of the soul. Note that unlike the standard theory, this up-front requires substance dualism of some sort, since the observing entity is not physical given the sui generis nature of the “observation” relation.

The non-causal dualist theory allows one to maintain forwards closure of the physical and the physicality of the brain. For the brain doesn’t cause a non-physical effect. The brain simply gets “observed”.

It is however possible that the soul causes an effect in the brain—for instance, the “observation” relation may trigger quantum collapse. Thus, the theory may violate backwards closure. And that’s fine by me. Backwards closure does not follow conceptually from the concept of the physical—a physical thing doesn’t become spooky for having a spooky cause.

There is a difficulty here, however. Suppose that the soul acts on the “observed” data, say by causing one to say “You stepped on my foot.” Wouldn’t we want to say that the brain data correlated with the pain caused one to say “You stepped on my foot”?

I think this temptation is resistable. Ridiculously oversimplifying, we can imagine that the soul has a conditional causal power to cause an utterance of “You stepped on my foot” under the condition of “observing” a certain kind of pain-correlated neural state. And while it is tempting to say that the satisfied conditions of a conditional causal power cause the causal power to go off, we need not say that. We can, simply, say that the causal power goes off, and the cause is not the condition, but the thing that has the causal power, in this case the soul.

On this story, if you step on my foot, you don’t cause me to say “You stepped on my foot”, though you do cause the condition of my conditional causal power to say so. We might say that in an extended sense there is a “causal explanation” of my utterance in terms of your stepping, and your stepping is “causally prior” to my utterance, even though this causal explanation is not itself an instance of causation simpliciter. If so, then all the stuff I say in my infinity book on causation should get translated into the language of causal explanation or causal priority. Or we can just say that there is a broad and a narrow sense of “cause”, and in the broad sense you cause me to speak and in the narrow you do not.

I think there is a very good theological reason to think this makes sense. For we shouldn’t say that our actions cause God to act. The idea of causing God to do anything seems directly contrary to divine transcendence. God is beyond our causal scope! Just as by forwards closure a physical thing cannot cause a spiritual effect, so too by transcendence a created thing cannot cause a divine effect. Yet, of course, our actions explain God’s actions. God answers prayers, rewards the just and punishes the unrepentant wicked. There is, thus, some sort of quasi-causal explanatory relation here that can be used just as much for non-causal dualist perception.

Fading knowledge of qualia

I am one of those people who do not have vivid memories of pains.

Suppose I stub my toe. While the toe is hurting, I know what the toe’s hurting feels like. After it stops hurting, for a while I still know what that felt like. But I know it less and less well as my memory fades, until eventually I know very little how it felt like. The whole process might take only a few minutes.

Thus, that mysterious “knowing what it’s like” involving qualia is something that comes with a parameter that varies as to how well you know it.

This should worry physicalists. Thin physicalists should worry because it doesn’t seem that the fading corresponds to any knowledge of the underlying physical reality. Thick physicalists who think that Mary just acquires a new recognitional concept when she sees red should worry, because it does not seem that there is any gradual loss of a concept. I continue to have the same “that experience” concept (the demonstrative “that” points to the same past experience, and does so in a first-personal way) and the recognitional abilities it enables (I can tell if another pain is like that one or not), even as my knowledge of what “that experience” is like fades.

It’s also not completely clear what a dualist should say about the fading of the knowledge. Normally, when knowledge fades, what happens is either that we lose details (as when I forget much of what I once learned in school about the Metis uprising), or we find the dispositional knowledge harder to make occurrent. But the fading is neither of these. Maybe what is happening is that our present knowledge becomes a less good representation of what it is the knowledge of.

Two common intuitions

Here are two very common intuitions in the philosophy of mind:

1. Our experiences of the same things are approximately qualitatively the same: your perceptual experiences of white, or squareness, or the beat of a drum are approximately like mine.

2. It is metaphysically possible to remap all of one’s qualia, so that one could have had all the color perceptions in one’s life rotated by 120 degrees, say.

I find myself somewhat sceptical of each. Moreover, each claim makes the other less likely, so the probability that both are true is less than the product of the probabilities of each.

Of the two claims, the first seems fairly plausible to me, because I am attracted to the idea that the qualitative properties of my perceptions arise from typical interconnections (including, but perhaps not limited to, inferential ones) between them, and we all have roughly the same ones. But this line of thought, while supporting (1) also supports the denial of (2).

Moreover, our use of the same word “red” for your and my experiences of red tomatoes suggests that (1) is a part of our ordinary pre-theoretic beliefs. And I am inclined to trust our ordinary pre-theoretic beliefs.

On the other hand, it could turn out that (1) is false because it could turn out that how red things look is partly a function of features of brain organization that differ from individual to individual (and in the same individual over time). If so, then we might want to disambiguate ordinary language’s “looks the same” relation to mean either having the same qualitative experience or having an experience with the same representative content, so that we could continue to say that when you and I are looking at a red tomato, it looks the same to us in the representative but not qualitative sense.

But in any case all this is deeply mysterious stuff. I am strongly inclined to the idea that we should try to figure out the best theory of mind and perception we can, and then use that to figure out if (1) and (2) are true, rather than using (1) and (2) as constraints.

Second-order perception and the knowledge argument

Here’s something odd in the knowledge argument as usually formulated. According to the knowledge argument, Mary who was raised in a black and white argument but knew all of science came to know what it is like to see red by seeing red, despite having known all the physical facts first.

But note that one cannot simply come to know what it is like to see red by seeing red. One knows what it is like to see red by having the second-order perception of oneself seeing red. When one has the first-order perception without the second-order one, one doesn’t directly know that one has the first-order perception. (One may be able to infer it, of course: Here is a tomato, my eyes are open and are pointed towards it, so I am seeing it.) Of course, typically when one has the first-order perception, one also has the second-order perception (but typically not the third-order one), but the point remains is that it is not by the first-order perception, but by the second-order one, that one learns what it is like to see red.

Presumably, any ordinary human perception can be mistaken: it can occur in the absence of its object. Thus it is possible to have the second-order perception without the first-order one. It follows that it is possible for Mary to know what it is like to see red without ever seeing red: all she needs is the second-order perception.

This does not seem to me to damage the knowledge argument as such, but merely to tweak it. For even after the above reflection, it still seems plausible that one doesn’t know what it is like to see red on the basis of physical facts, but by means of a second-order perception. Moreover, we now have an answer to the memory objection to the knowledge argument, namely that just as you and I can know what it is like to see red by having true memories of seeing red, so too someone could know what it is like to see red by having false memories of seeing red, and so actual perception of red is not needed. But this does not affect the argument once we have realized it’s about the second-order perception. For memories, true or false, of seeing red are a kind of temporally backwards second-order perception.

More on the non-causal dualist theory of perception

In a recent post, I offered a non-causal dualist theory of sensory awareness on which when I see a red cube, there is a state r_b of my brain representing the red cube, and a relation V of perception between r_b and my soul, which relation is external to the soul. As a result, there need be no intrinsic difference between my soul when I am perceiving red cube and my soul when I am not perceiving a red cube.

I want to make a few more notes on this theory, for it seems to me that it is worth taking seriously.

1. This theory is very close to Aquinas’. Aquinas thought that sensory awareness was constituted by the reception of sensory data (“phantasms”) by sense organs. The sense organs, and not the soul, are modified by the sensory awareness. Of course, it was crucial to this that the sense organs be informed by the form of the animal, and the form of an animal is the soul. So we have a similar structure: there is a relation of the soul and the sense organs, and the sense organs are then modified by the sensory data. If we neglect the difference between the brain in my theory and the sense organs in Aquinas’s, then Aquinas’s theory is just an expansion on my theory. The state r_b is the state of the sense organs having their sensory data, and my external relation V of perception on Aquinas’s view is simply constituted by a pair of relations on Aquinas’s: the informing relation of the soul to the organ, and the sensory-data-possession relation between the organ and its sensory data.

Thus, the main difference between my theory and Aquinas’s is that I replace the sensory organs with parts of the brain. And there is good reason to think that if Aquinas had the empirical data we do, he would think of the phantasms as in the brain rather than in the eyes, ears, etc. For we have good reason to think direct neural stimulation of the visual center of the brain could produce the same visual experience as gazing upon a red cube. Thus, the only difference between Aquinas and the theory—apart from Aquinas offering more detail on the relation V—is that on the theory, the sensory organs in Thomas’s sense are all inside the skull.

2. What we should say about qualia on this theory? The analogue to the visual quale of my perceiving a red cube on this theory consists of V and r_b. That’s a pair of things rather than one thing. One of these two things, the brain state r_b, is physical, but the other thing, the relation V, is a non-physical relation between a non-physical thing, the soul and a brain state r_b. Thus qualia are partly non-physical and partly physical.

3. It seems the theory contradicts the knowledge argument. Consider the brain state r_b representing a red cube and the brain state g_b representing a green cube. It seems that on the basis of seeing a green cube, I can get to know the relation V obtaining between my soul and g_b. And on the basis of neuroscience, I can get to know r_b. Thus, without ever seeing anything red, it seems I can know what it’s like to see red.

I am not strongly attached to the knowledge argument in its standard form. I kind of like the radical variant on which a never conscious person could never get to know what consciousness is like. And that variant fits with the theory, since a never conscious person has never experienced the relation V. (You might say: A never conscious person couldn’t know anything. I think it is a mistake to require consciousness for knowledge. First, one can have non-occurrent knowledge without consciousness—I know my multiplication tables even when asleep. Second, the unconscious vampires in Watts’ Blindsight clearly have knowledge.)

That said, I do not think it is obvious that just by knowing what the ingredients are like one knows what the whole is like. Thus, knowing what r_b and V are like may not be enough to know what it is like to have one’s soul stand in V to r_b. (Compare: Alice knows what it is like to be married to Bob, and she knows Carl, but it doesn’t follow that she knows what it is like to be married to Carl.)

A weird escape from the Knowledge Argument?

Take Jackson’s story about Mary who grows up in a black-and-white room, but learns all the science there is, including the physics and neuroscience of color perception. One day she sees a red tomato. The point of the story is that in seeing the red tomato, she has learned something, even though she already knew all the science, so the science is not all the truth there is, and hence physicalism is false.

This story is generally told in the context of the philosophy of mind, and the conclusion drawn is that physicalism about the mind is false. But that does not actually follow without further assumptions. As far as the argument goes, perhaps Mary didn’t learn anything about herself that she didn’t already know, but has learned something about tomatoes, and so we should conclude that physicalism about tomatoes is false.

Let’s explore that possibility and see if this hole in the argument can be filled. I will assume (though I am suspicious of it) that indeed the kind of knowledge gap that Jackson identifies would imply an ontological gap. Thus, I will accept that Mary has learned what it is like to see the red of a tomato, and that the knowledge of what it is like to see the red of a tomato is not a knowledge of physical fact.

Can one say this and yet accept physicalism about the mind? The one story I can think of that would allow that is a version of Dretske’s qualia externalism: just as most of us think that the content of our thoughts is partly constituted by external facts, so too the qualitative character of our perceptions is partly constituted by external facts. But in fact for the story to work as a way of blocking the inference to non-physicalism about the mind, the qualia (understood as that in the experience that cannot be known by Mary by mere book-learning) would need to be entirely constituted by extra-mental facts.

I think this kind of qualia externalism is not all that crazy. Divine simplicity requires that all of God’s knowledge of contingent fact be partly constituted by states of affairs outside God. But it is plausible that God has something like contingent qualia: that were God to contemplate a world with unicorns, it would “look” different to God than our world. On divine simplicity, we would need to have externalism about these qualia.

That said, the above affords no escape from literal anti-physicalism about the mind. If physicalism about the mind is true, then minds are brains. But if we accept that colored things have a nonphysical component that partly constitutes the perceiver’s qualia, then brains have a nonphysical component, since brains are colored things, namely pinkish (here is a description of their color in vivo, though I cannot vouch for its accuracy).

Maybe, though, this misses the point in the debate. The typical dualist thinks that there is something different about minds and other physical things. If it turns out that minds are just brains, but that they are not physical simply because their pinkness is not entirely a physical property, that’s really not what the dualist was after. The dualist’s intuition is that there is something radically different in the human brain, something not found in a pink sunset cloud (unless it turns out that panpsychism is true!).

Maybe this works to save a more robust dualist conclusion: Plausibly, one doesn’t need a tomato to make Mary have a red sensation. All one needs is to do is to induce in her brain’s visual centers the same electrical activity as normally would result from her seeing a red tomato. And the equipment inducing that electrical activity need not be red at all.

Reid's critique of Aristotelian accounts of perception

Reid thinks that the Aristotelians make the same mistake as the Lockeans and Berkeleians: they all think that the phenomenal qualities or “ideas” (in the Lockean sense) in our minds are similar to the properties of physical objects. Thus, the sensation of hardness when I press my hand on the table is supposed to be similar to the physical hardness of the table. But Reid thinks that a bit of reflection shows that the mental entity is quite different from the physical entity.

Presumably, the reason the Aristotelian is accused of this mistake is that the Aristotelian is supposed by Reid to think that a single objectual quality, such as hardness, is found in the table and in the mind (presumably in different ways).

However, I think the criticism of the Aristotelian fails. Let’s take the Aristotelian theory to be as Reid seems to think of it. We still have a choice as to what item in the Aristotelian view we identify with the phenomenal qualities. There is

1. the hardness itself

and

2. the sort-of-but-not-quite-inherence relation between the mind and the hardness.

Which one of these is the phenomenal quality or “idea”? The difficulty here is that Reid seems to accept two claims about Lockean “ideas”:

3. we always have immediate awareness of “ideas”

and

4. “ideas” are the states of awareness.

On the Aristotelian view in question, (1) satisfies (3) and (2) satisfies (4). But (1) does not satisfy (4), and I don’t think the Aristotelian should allow that (2) satisfies (3).

The Aristotelian can now give this story in response to Reid. If we identify (1) as the phenomenal quality, the “what I feel”, then there is nothing absurd about saying that what I feel—namely, hardness—is what is in the extramental table. If we identify (2) as the phenomenal quality, on the other hand, then the Aristotelian will agree with Reid that the phenomenal quality is not found in the extramental object, because the inherencish relation is only found in the mind.

In fact, the Aristotelian’s refusal to accept that there is a single sense of “ideas” that satisfies (3) and (4) is a very good thing. For if we accept both (3) and (4), then for anything we are aware of, our state of awareness will itself be something we are aware of, and any awareness will immediately imply infinitely many levels of higher-order awareness, which is empirically false.

I am not a Reid scholar, however. I might be badly misreading Reid.

A tale of two universes

Suppose that Mary lives in a universe whose physics is radically different from ours. She loves mathematics and is amazingly good at it. She has very little knowledge of biology, beyond what little superficial information she can glean by turning her eye-stalks on herself while spending all her life suspended in a vortex of Z-force. One day, she is given a complete description of the physical state of the laws of our universe and of the physical arrangement of matter in the Solar System over the past billion ears. She thinks this is really cool mathematically, and thinks through all the mathematico-physical facts involved.

Here is the question: Does Mary have enough information to know that the Solar System contains conscious life?

If not, physicalism seems to be in trouble.

Another variant of the knowledge argument

We don’t have anybody like Mary who knows all of physics and yet has not yet seen color, and as Dennett has pointed out, it is hard to imagine what things look like from the point of view of someone who knows so much more than we do.

But here is a variant that may be easier for us to wrap our minds about: Imagine two people, one a completely colorblind early 21st century neuroscientist specializing in the visual system and the other a completely colorblind ordinary person. Suppose both receive color vision. If physicalism is true, the neuroscientist knows a lot more about what seeing red is like, even though (because we’re still in the early days of neuroscience) they don’t know that much about it overall. Thus, if physicalism is true, the neuroscientist would learn less by seeing red the first time, and should be less surprised. But would we really expect them to learn less and be less surprised than the ordinary person?

This variant is inspired by a remark I heard Brandon Rickabaugh give in a conference talk, that consciousness only seems more mysterious when one knows more neuroscience.