3.a Materialism and compound dualism

Remember that according to compound dualism, we have material parts as well as an immaterial one. As far as compound dualism says, any of the leading materialist candidates for what we are could be parts of us. So, a certain kind of compound dualist could say that I have an entire human animal as a part. To reiterate what this implies: the fact that you visually represent me as being 5’ 6" is no threat to compound dualism. According to the animalist version of compound dualism, I am 5’ 6". Your experience isn’t going to be partial toward materialism (as against compound dualism) just in virtue of the fact that it represents my having sensible properties.Footnote ¹³

If it’s not going to be in virtue of representing one another as 5’ 6", how might our experience nonetheless fail to be neutral between materialism and compound dualism? I can think of two basic ways, one negative and one positive.Footnote ¹⁴

The negative way is so-called because it’s a matter of our representing an absence—a negative fact. When you look at me and I’m not wearing a cowboy hat, then if all is right with your vision, I won’t look to you like I’m wearing a cowboy hat. That is, your experience won’t have the content Aaron is wearing a cowboy hat. So much is obvious. But even more seems to be true. You’ll seem to see the absence of any cowboy hat atop my head. That is, your experience will have the content Aaron is not wearing a cowboy hat. If it turns out I am wearing a cowboy hat, and the angle at which the light reflected off the hat made it so that it looked to you just like it does when I’ve got no hat, then your experience will have been partially falsidical, rather than merely incomplete. It will have misrepresented the situation as one in which there’s no hat atop my head, when in fact there is.

Thus, one might suggest that our experiences (or some experiences, had by some of us) represent the world as lacking in immaterial things; or, at least as lacking in immaterial concrete things; or, at least as lacking in immaterial spirits, ghosts, and souls. More narrowly, you might suggest, our experience represents situations involving human organisms as lacking in any immaterial things “hooked up” to the relevant organism/part—as being the kind of situation in which there is no immaterial thing in the vicinity of the organism/part, or in causal contact, or harmonized with it.

My response to this is twofold. First, I doubt that we could really represent any of this visually—or any other experiential way. Start with an experience of another human organism that is “silent” on whether there is an immaterial soul “hooked up” to it. (I’m supposing that even someone who thinks that we can experientially represent the absence of an immaterial soul will concede that we can have an experience that is silent on the question.) Now: What can you add to the experience—more exactly, what can you change phenomenally—such that it’ll now represent the absence of an immaterial soul? Is there anything? If so, it’s very mysterious what it would be. Assuming that content supervenes on phenomenology, there doesn’t seem to be any way we could get the experience to represent the absence of an immaterial soul hooked up to the organism.

In addition to such appeals to mystery, we can give a more direct and positive argument that there’s no way for us to represent the absence of the soul—at least not without already representing the presence of something that would all by itself tell in favor of materialism. How do you manage to represent the absence of a cowboy hat atop my head? Why is it that you don’t also represent the absence of loads of subatomic particles whirling around?

A pretty plausible account (developed by Farennikova [Reference Farennikova2013]) of perceptually representing absence is that you match, or compare, an expected scene (a scene that includes a cowboy hat on top of my head) to the scene you actually meet (a scene in which you can look right above my head and see sky); and in (visually) representing the difference between the two scenes, you thereby (visually) represent the absence of a cowboy hat. If that account is right, in order to detect the absence of something, the absence of that thing has to make a discernible difference to something else in the scene, something that isn’t an absence (else the account will be circular). That is, representations of absences are parasitic on representations of differences between presences. But then this “negative way” for our experience to fail to be neutral between materialism and compound dualism doesn’t stand on its own; it requires a “positive way” for our experience to fail to be neutral. And we’ll get to that way next. For the moment, then, we can set this possibility aside.

But let’s grant that we can experientially represent the absence of a soul. Remember, though, that in order for such an experience to make us perceptually justified in believing that there’s no soul, it has to be the case that it’s possible to perceive the absence of a soul (more exactly, its being the case that there is no soul “hooked up” to this organism). (At least that’s what I’ve been assuming until now. I will return to a justification of this assumption.) And I think it’s pretty clear that we can’t possibly perceive that absence—not just given the perceptual faculties we have, but given any perceptual faculties we could have had.

It’s hard enough to understand how we can perceive (as opposed to merely experientially represent) absences in general (if we can). After all, absences don’t seem to be the kinds of things that could cause anything.Footnote ¹⁵ And it’s relatively uncontroversial that in order to perceive X or p’s being the case, X or p has to stand in some causal relation to the perceiver. But whatever solution we propose to the general problem is not going to help us understand how we could perceive an absence of something that, were it present, would be imperceptible.

Suppose, for example, that we take our cue from Jonathan Schaffer’s solution to the puzzle of absence causation. Partly to address the puzzle of how there could be any such thing—given that absences, even if there are such things, don’t have any causal oomph—Schaffer (Reference Schaffer2005) puts forward a contrastive model of causation: causation “is a quaternary, contrastive relation: c rather than C* causes e rather than E*, where C* and E* are nonempty sets of contrast event.” In the case of causation by absences, C* is nonactual. Thus, the truth that the gardener’s failure to water the plant caused it to wilt is to be understood as follows (suppose he was napping instead): the gardener’s napping (c) rather than watering the plant (C*) caused the plant’s wilting (e) rather than blossoming (E*). And that’s true because c and e occurred, but if C* had occurred instead of c, then E* would have occurred instead of e. Thus, we can speak correctly of absences being causes without having to assume that absences really have any oomph.

We might extend this to account for perception of absences. Thus, we might say that you perceive the absence of (some nonactual state of affairs) just in case (a) you perceptually represent the absence of that state of affairs, and (b) were that state of affairs present, you would perceive it. Thus, we can speak correctly of absences being perceived, without having to assume that absences are really perceptible.

But this account will only allow us to speak correctly of the perceptible absence of things, like cowboy hats, which if they were present would be perceived in the straightforward sense. Souls are not like cowboy hats in this regard. You wouldn’t see or hear or smell them if they were present. Their absence literally makes no perceptible difference, and so their absence is imperceptible.Footnote ¹⁶ That’s true given the account we just suggested. But it seems like any account of absence perception should respect that truism: you can perceive the absence only of something you could perceive were it present. The soul’s absence is no more perceptible than its presence.

Concluding this discussion of the negative way, and putting matters in terms most relevant to representational neutrality: our perceptual experience is insensitive to this particular difference between materialism and compound dualism—the difference between the absence and presence of a soul—whether or not it is silent on that difference.

So much for the negative way. Now for the positive way. The positive way is so-called because it’s a matter of representing a presence—a positive fact—presumably, some fact having to do with thinking, consciousness, or personhood. But we need to be precise here. Remember, the fact that when looking “in my direction” you seem to see that there’s something that’s both 5’ 6" and conscious introduces no partiality toward materialism over compound dualism. According to compound dualism (at least those versions of compound dualism that says I have a whole human animal as a part) I am both 5’ 6" and conscious. So the experiential representation of material things as in some way mental has to be more specific in order to be partial toward materialism.

I can think of two ways our experiential content might be more specific in this respect. One way would be if our experiences represent some event, or activity, or process as both material (consisting in the activities of material objects) and mental (consisting in the activity of thinking). Thus, we might look at a brain and visually represent that there is thinking going on in that brain. This claim—that there is thinking going on in the brain—is inconsistent with dualism+. Again, no sane dualist of any stripe would think that that there are material processes that are themselves episodes of consciousness. There’d be too much consciousness about.

But I don’t think our sensory experiences represent that claim as being true. We need to keep in mind the distinction between genuine consciousness and functional indistinguishability from consciousness. (It goes without saying that a functionalist will deny that there’s any distinction here. I’m relying here on the falsity of functionalism. This is a legitimate assumption to make in this context: if functionalism is true, then evidently material things do think and are conscious, and so dualism+ is false. That is, if functionalism is true, there’s no need to rely on perceptual evidence to support materialism, since it just follows from the truth about what mentality is.Footnote ¹⁷ So my whole discussion can be seen as conducted under the supposition that functionalism is false.) It doesn’t seem to be the case that our sensory experience represents the presence of consciousness (as opposed to them representing the presence of either consciousness or functional indistinguishability from consciousness). It’s in fact commonplace in the philosophy of mind literature that we don’t seem to see consciousness when we look at things like brains, central nervous systems, and organisms. I suspect we don’t seem to see consciousness because we can’t, and that we can’t because of the chasm between the view from inside (which is how we can become acquainted with consciousness) and the view from outside (which is the only view that sensory experience can give us).Footnote ¹⁸ Thus, even when we look at ourselves—in the mirror, or even on a screen during brain surgery—we don’t seem to see the subjective awareness as much as see a thing, and be separately acquainted with its being a subjectively aware thing. This, of course, is the heart of Leibniz’s Mill argument.Footnote ¹⁹

There is another way that our experiential content might be more specific in mental respects, and in a way that is partial toward materialism. Suppose we experientially represent a certain material thing as itself having some mental feature or other. Thus, perhaps some of our sensory experiences have as content that dog over there is in pain. Maybe that’s just abstract enough that we can sensorily represent it as being the case, even though we can’t, as I’ve just argued, sensorily represent the undergoing of that pain, the subjective painful awareness.

The content in question—that the dog over there is in pain—may, or may not, be consistent with dualism+. It depends on what the content is exactly. If the content is that the canine animal over there—the organism over there, which has nothing but material parts—is in pain, then it’s indeed inconsistent with dualism+. As before, no sane dualist of any stripe would think that some wholly material object like a canine animal has genuine mental properties. If a canine animal has genuine mental properties, then so, presumably, does a human animal, and there’d be too many thinkers about. If, on the other hand, the content is more neutral about the bearer (how far it extends and what its parts are), then it might well be consistent with dualism+. So our experience will be partial toward materialism over compound dualism on these grounds only if we can be perceptually justified in believing a very specific claim about property bearers, such as that the canine animal itself feels pain—that the thing that instantiates the property of being in pain is a canine animal.

Now, I’m willing to grant that we can experientially represent such a thing. And I’m even willing to grant that we sometimes do experientially represent such a thing—although I doubt such a specific sensory representation is very common. But even if we sometimes do so, I don’t think that specific content is perceptible. It’s too specific to make any causal difference—and a fortiori any perceptible difference.

Suppose that as a matter of fact the thing that instantiates the property of being in pain is a canine animal. And now ask, under that supposition, if it hadn’t been true that the thing that instantiates the property of being in pain is a canine animal, what would have been the case? I don’t know. But I very much doubt that what would have instead been the case is something different enough that it would have looked or smelled different. Presumably the metaphysics of mental property bearers would have been slightly different, so that something else, bigger or smaller, would be the property bearer. And that situation would have looked and smelled just the same.Footnote ²⁰

Note that this is very different from our perception of far less specific content, such as there’s a tree out there. That’s sufficiently nonspecific so that in order to get to a situation in which it’s false with as little departure from actuality as possible, you’d have to go to a situation that is perceptibly different. In order to get back to a scenario in which things look and feel the same, we’d have to go much further—to some sort of skeptical scenario involving evil geniuses or BIVs. So nothing I’ve said rules out our perceiving that there’s a tree out there.Footnote ²¹

So much then for the positive way for our experience to be sensitive to the difference between materialism and compound dualism. This wraps up my case for the claim that our experience is perceptually neutral between materialism and compound dualism.

3.b Compound dualism and pure immaterialism

While it took some work to argue for that claim about materialism and compound dualism, I think it’s a relatively innocuous claim. But, as I said earlier, once we’ve taken that claim on board, my conclusion follows not too far behind. And that’s because, as I see it, our experience is perceptually neutral between compound dualism and pure immaterialism.

The difference between compound dualism and pure immaterialism, as you’ll recall, is a difference about which things we are. This difference leads to a number of other differences: especially regarding which things are conscious, and which are persons. But it’s important to note just how much common ground there is, or at least can be, between the two sides.

For one thing, they need not differ over any ‘ontological’ question—any question about what there is or how many things there are of a given kind. They will both agree about the existence of immaterial souls, and how many there are. They can both agree about the existence of material things, and how many and which ones there are. And, what may not be as obvious but is still true, they can even agree about which material/immaterial amalgams there are. Compound dualism is committed to there being such amalgams, because it identifies each of us with some one of them. But pure immaterialism is also consistent with there being such amalgams—and even with there being exactly the same ones as there must be according to compound dualism. Pure immaterialism says that you and I are wholly immaterial; it doesn’t say that everything is either wholly material or wholly immaterial, and it’s consistent with me and my body composing something further.

For another thing, they’ll agree about all of the basic qualitative facts: this includes facts about the size and shape and weight and color of human bodies and brains, and it includes facts about where (or, in which things) there is mental activity going on.Footnote ²² And for one final thing, they can agree about all of the causal facts: this includes facts about the interaction between the immaterial thinking things and material things such as human brains.

So the facts over which the two views will differ are rather limited, and seem to be of just two kinds: ‘conceptual’ facts and ‘haecceitistic’ facts. The conceptual facts are things like: given that the basic qualities are distributed over things in such a pattern, and there are mental processes going on over here and there, and these things stand in causal relations to those things, then such-and-such counts as a conscious being, and a person. The haecceitistic facts are things like: given that the basic qualities are distributed over things in such a pattern, and there are mental processes going on over here and there, and these things stand in causal relations to those things, then so-and-so is Abe, or you.

Now, I’m willing to grant that we can experientially represent such things. And I’m willing to grant that we sometimes do experientially represent such things.Footnote ²³ But I don’t think that these facts are perceptible. They’re too metaphysical to make any perceptible difference. They’re just not the kinds of things that our perceptual faculties can detect.

Suppose, per impossibile, God tells you he’s created two planets as much like Earth as the following stipulations allow. One is inhabited by human people whose nature is the same as what compound immaterialism says our nature is, and the other is inhabited by human people whose nature is what pure immaterialism says our nature is. (If materialism is true, neither of these planets is exactly like Earth. And I say “per impossibile” because I assume that whatever the truths are about the concept person won’t vary from world to world, let alone planet to planet.) On both of these planets, whenever and wherever there is a human person, there is an immaterial soul and a body that are intimately connected with one another: there is a two-way, direct, and immediate causal connection between the soul and the body. And the causal connection between them is exactly the same on the two planets. Moreover, on both planets the same number of total objects exist, located in the same places; and basic qualities, both physical and mental, are distributed in the very same way on both.

And then suppose God tells you that you and your friend Abe are human persons who inhabit one of these two planets, but He doesn’t tell you which one. Would you be able to tell by looking—whether at Abe or at yourself—which planet you’re on? I don’t see how you possibly could. No difference between the two scenarios would be picked up by your visual, or olfactory, or whatnot perceptual system.

This wraps up my case for the claim that our experience is perceptually neutral between compound dualism and pure immaterialism.

3.c Transitivity of perceptual neutrality

As I already noted in section 3, the final step of the argument is to bring these two claims of perceptual neutrality together so as to yield the conclusion that our experience is perceptually neutral as between materialism and pure immaterialism as well.

1. 1. Our experience is perceptually neutral between materialism and compound dualism.

2. 2. Our experience is perceptually neutral between compound dualism and pure immaterialism.

Therefore,

1. 3. Our experience is perceptually neutral between materialism and pure immaterialism.

From which premises and conclusion it follows that: if our experience represents matters in a perceptible way that’s inconsistent with pure immaterialism, that can only be because it represents it in a perceptible way that’s inconsistent with our existing. So we’re perceptually justified in believing something incompatible with pure immaterialism only if we’re perceptually justified in denying our existence. It’s fairly obvious that we’re not perceptually justified in denying our existence. So we get my conclusion that we’re not perceptually justified in believing anything incompatible with pure immaterialism.Footnote ²⁴

But the inference of (3) from (1) and (2) is valid only if perceptual neutrality (relative to some set of experiences) is transitive. Or, at least I see no way to vindicate the validity of that inference unless we can assume that it’s transitive. But is it? The intuitive gloss on perceptual neutrality—as a matter of being insensitive to the difference between the two claims—might initially make it seem obvious that it’s transitive. But for those of us familiar with sorites series of phenomenal indiscernibility, the gloss might instead give us pause. After all, isn’t a failure of transitivity exactly what we have regarding the relation of phenomenal indiscernibility? (The claims that the truck looks red_1,238,987 and that it looks red_1,238,988 are phenomenally indiscernible; and more generally, for any n, the claims that the truck looks red _n and that it looks red _n+1 are phenomenally indiscernible; and yet the claims that the truck looks red₁ and that it looks red_1,238,988 are not phenomenally indiscernible.) Isn’t that at least one of the lessons of the phenomenal sorites? And isn’t phenomenal indiscernibility just a matter of our perceptual experience being insensitive to the difference between the claims?

Fair question. First, it’s worth noting that not everyone agrees that the failure of transitivity of looking the same, or phenomenal indiscernibility, is the right lesson to draw. Some philosophers (Fara Reference Fara2001; Raffman Reference Raffman2000) take its transitivity as a truism, or at least as true, and so deduce that there can’t really be any genuine cases of a phenomenal sorites (only ones that we mistake for a phenomenal sorites).

Second, the relation could be restrictedly transitive. That is, it could be that there is some rather natural/simple condition φ such that if p and q are phenomenally indiscernible, and q and r are phenomenally indiscernible, and φ (p, q, r), then p and r are indiscernible. Perhaps φ is a condition that rules out vagueness as an explanation of the twin phenomenal indiscernibilities. Since vagueness seems not to be part of the explanation for the perceptual neutrality (of our experience) between materialism and compound dualism, and seems not to be part of the explanation for the perceptual neutrality (of our experience) between compound dualism and pure immaterialism, we could rely on such a restricted transitivity principle to license the inference in the above argument.

But third and most importantly, even opponents of the transitivity of phenomenal indiscernibility acknowledge that there are several relations in the vicinity, some of which are demonstrably transitive. And the relation I have in mind is demonstrably transitive. It’s a matter of our perceptual experience failing to pick up on any fact that speaks in favor, so to speak, of one over the other. Here’s a more careful definition:

1. 1. r entails p iff r entails q, and

2. 2. r is consistent with p iff r is consistent with q, and

3. 3. r is inconsistent with p iff r is inconsistent with q.

As can be easily verified, this relation is transitive.Footnote ²⁵

In the case where p and q are incompatible (as in our hypotheses about human ontology), p ~_E q implies that for any perceptible proposition r such that E represents r as being true, (a) r entails neither p nor q, and (b) either r is consistent with both p and q or it’s inconsistent with both p and q. This is exactly why I said that from the premises and conclusion of my argument it follows that: if our experience represents matters in a perceptible way that’s inconsistent with pure immaterialism, that can only be because it represents it in a perceptible way that’s inconsistent with our existing. If there is some perceptible proposition r such that our experience represents r as being true, and r is inconsistent with pure immaterialism, then it follows (given the premises and conclusion of perceptual neutrality) that there is a perceptible proposition (i.e., r itself) that is inconsistent with pure immaterialism, materialism, and compound dualism. But it is a logical truth that if we exist, then either we are wholly material, or wholly immaterial, or some amalgam of material and immaterial parts. So then there is a perceptible proposition that is inconsistent with our existing.

One last point on this issue: one can in principle dispense with transitivity, and just argue directly that our experience is perceptually neutral between materialism and pure immaterialism. It’s not that the arguments above for each of the premises won’t come in handy. They will, since they’ll help us see, regarding various candidate contents that might be partial to materialism over pure immaterialism, either that they are not perceptible, or that our experience doesn’t represent them as being the case. Indeed, we could in principle dispense entirely with the two premises, seeing them as ladders to be kicked away when we get to the end. That is, we could just examine a slew of candidate propositions, which are inconsistent with pure immaterialism, and argue that none is both perceptible and such that we represent it in experience as being true. One could give either one of those more piecemeal arguments. To my mind they’re less compelling, and less illuminating, than the original two-step argument. But they’re available if needed.