Monday, October 31, 2016

Realism and anti-reductionism

The ordinary sentence "There are four chairs in my office" is true (in its ordinary context). Furthermore, its being true tells us very little about fundamental ontology. Fundamental physical reality could be made out of a single field, a handful of fields, particles in three-dimensional space, particles in ten-dimensional space, a single vector in a Hilbert space, etc., and yet the sentence could be true.

An interesting consequence: Even if in fact physical reality is made out of particles in three-dimensional space, we should not analyze the sentence to mean that there are four disjoint pluralities of particles each arranged chairwise in my office. For if that were what the sentence meant, it would tell us about which of the fundamental physical ontologies is correct. Rather, the sentence is true because of a certain arrangement of particles (or fields or whatever).

If there is such a broad range of fundamental ontologies that "There are four chairs in my office" is compatible with, it seems that the sentence should also be compatible with various sceptical scenarios, such as that I am a brain in a vat being fed data from a computer simulation. In that case, the chair sentence would be true due to facts about the computer simulation, in much the way that "There are four chairs in this Minecraft house" is true. It would be very difficult to be open to a wide variety of fundamental physics stories about the chair sentence without being open to the sentence being true in virtue of facts about a computer simulation.

But now suppose that the same kind of thing is true for other sentences about physical things like tables, dogs, trees, human bodies, etc.: each of these sentences can be made true by a wide array of physical ontologies. Then it seems that nothing we say about physical things rules out sceptical scenarios: yes, I know I have two hands, but my having two hands could be grounded by facts about a computer simulation. At this point the meaningfulness of the sceptical question whether I know I am not a brain in a vat is breaking down. And with it, realism is breaking down.

In order for the sceptical question to make sense, we need the possibility of saying things that cannot simply be made true by a very wide variety of physical theories, since such things will also be made true by computer simulations. This gives us an interesting anti-reductionist argument. If the statement "I have two hands" is to be understood reductively (and I include non-Aristotelian functionalist views as reductive), then it could still be literally true in the brain-in-a-vat scenario. But if anti-reductionism about hands is true, then the statement wouldn't be true in the brain-in-a-vat scenario. And so I can deny that I am in that scenario simply by saying "I have two hands."

But maybe I am moving too fast here. Maybe "I have two hands" could be literally true in a brain-in-a-vat scenario. Suppose that the anti-reductionism consists of there being Aristotelian forms of hands (presumably accidental forms). But if, for all we know, the form of a hand can inform a bunch of particles, a fact about a vector or the region of a field, then the form of a hand can also inform an aspect of a computer simulation. And so, for all we know, I can literally and non-reductively have hands even if I am a brain in a vat. I am not sure, however, that I need to worry about this. What is important is form, not the precise material substrate. If physical reality is the memory of a giant computer but it isn't a mere simulation but is in fact informed by a multiplicity of substantial and accidental forms corresponding to people, trees, hands, hearts, etc., and these forms are real entities, then the scenario does not seem to me to be a sceptical scenario.


Heath White said...

This raises really interesting questions about what counts as a "skeptical scenario". Back in the heyday of verificationism, it was generally thought that Cartesian skeptical scenarios were cognitively synonymous with non-skeptical real life, so that "I am being deceived by an evil demon into thinking I have two hands" just meant the same thing as "I have two hands." And your strategy is somewhat similar.

Consider also that Berkeley's metaphysics is not all that far from being a brain in a vat (being a soul in the vat of divine stimulus). Yet that is not generally taken to be a _skeptical_ scenario.

And yet it sure does seem like, if I were a brain in a vat, I would not have two hands. Perhaps the difference is this: in the skeptical scenarios, there is the possibility of a perspective which (a) explains the sensations/beliefs we have, (b) gives some traction to the idea that these beliefs are in error, and (c) is such that the victim of the scenario does not know about this perspective. But if he did come to learn about this perspective, he would have the choice of whether to revise his beliefs, or reduce/analyze his beliefs into new terms.

For example, Wittgenstein considers claims like "this table is solid." Well, physicists tell us it is mostly empty space. The physical theory nevertheless (a) explains why we think it is solid, but (b) gives us some reason to think our naive view of solidity was in error. However, once we take the new theory on board, we can decide whether we were wrong ("matter is mostly empty space, not solid") or analyze our terms a little more carefully ("the table is solid because it cannot be easily penetrated by macroscopic objects").

I can imagine making similar moves about my hands if I were to come to believe I am a computer program running on an alien's laptop.

Alexander R Pruss said...


I always thought that Berkeley's metaphysics *is* a sceptical scenario.

I think in the fundamental physics scenarios we have (a)-(c) as well, as long as we have reductionism in the sense that there is nothing in the fundamental ontology besides the fundamental physics.

Thanks for bringing up Eddington's table. I had forgotten about that.

"[I]f he did come to learn about this perspective, he would have the choice of whether to revise his beliefs, or reduce/analyze his beliefs into new terms."

This is too Hegelian for me.

But I am in principle OK with a similar move being made in *some* cases. I think it might have been vague in the 15th century whether "Dolphins are fish" is true. The word "fish" could then have been precisified according to the anatomy / genetics / history or it could have been precisified according to gross morphology and habitat or there could have come to be two communities of use. (Compare how "berry" was differently precisified by the overlapping(!) biological and culinary communities.) But it's not up to us whether a 15th century English speaker saying "Dolphins are fish" (or a cognate) is saying the truth. If it was vague at the time, it's still vague whether they were saying the truth. Rather, language has shifted--precisified--and what used to be vague is now non-vaguely false.

Could one make the same move wholesale, though, about all of the common sense world? I am not sure. I think that this might be cutting the branch we're sitting on, both evidentially and semantically.

By the way, a similar thing comes up with regard to eliminativism about the mental. There the branch-cutting danger is even more vivid.

Alexander R Pruss said...

Another related case is this: The disagreement between libertarians of whether, if we learned determinism is true, we would thereby learn that compatibilism is true or that we have no free will.

Michael Gonzalez said...

I'm surprised no one has mentioned Kripke or "rigid designators" yet... But, since I have very little use for Kripke, I'll leave well enough alone :-)

It seems to me that there is an issue right from the beginning. "There are four chairs in the room" presumes an accepted meaning of the terms "chair" and "room" (and "four", for that matter), and that it is now physically true that those actual objects are present within that other actual object. If a brain-in-vat scenario were true, then it would be false that there are any chairs at all, let alone 4 of them in a room. There are no rooms. It is all an illusion.

But, what about physical ontologies? Here is the key (I think): Any physical ontology which permits an object to actually possess the properties we associate with chairs is permissible. Brain-in-vat ontologies do not. And I am very skeptical as to how a Copenhagen, Many Minds, or flashy GRW interpretation of QM could permit this either. Therefore, quite simply, we ought to reject those interpretations unless they are rationally forced upon us. We should, indeed, hold back accepting that tables are mostly empty space until this fact is forced upon us. And even the "forcing" is via other things which we know to be true in the same general way that we know about chairs.

We are animals exploring a world of objects and communicating about them with languages. An existential sentence is only true if we agree about the minimum requirements for an object to qualify as X (say, a chair) and the object before us meets those minimum requirements. Everything else about the bits and pieces is irrelevant.

Now, if I claimed that a wooden chair is in the room, and it turned out to be plastic that just looks like wood, then I would have spoken falsely. But that's only because I actually ventured to make a statement about the physical pieces of which the chair is made. If I stop at "chair", then ANY material is fine and indeed any physical ontology so long as it permits the properties associated with chairs simpliciter.

Alexander R Pruss said...

One problem, though, is what these "properties associated with chairs" are. Take extension. We have many metaphysical theories of extension, with the main two being: (a) extension is occupation of the right kind of plurality of points; and (b) extension is a function of the right kinds of spatial relations between the parts of an object. And then there will be many theories of "points" and "spatial relations".

And many of these theories are compatible with realism about chairs. But it seems that not all. Consider this theory: spatial relations are constituted by relative distance data in the alien's laptop's file constituting the chair.

But why would many but not all candidates for spatial relations--yet all of which have the same formal and functional properties--make for realism about extended objects? What is the difference?

Alexander R Pruss said...


Here's what I am currently thinking. If it turns out that there is nothing like forms at the macroscopic level and that none of the concepts of the common-sense world except for minds cut at the fundamental joints, then we are living in a sceptical hypothesis. It doesn't matter if the substrate of that hypothesis is the alien's laptop, or a demon inducing experiences, or a bunch of particles behaving according to Newtonian or quantum laws. All these are sceptical hypotheses.

On the other hand, if it turns out that enough of the concepts of the common-sense world genuinely cut at the fundamental joints, say because there fundamentally are forms that define such joints, then we are not living in a sceptical hypothesis. It doesn't matter if the substrate is the alien's laptop, or a demon inducing experiences, or a bunch of particles behaving according to Newtonian or quantum laws, as long as somehow enough of our common-sense concepts cut at the fundamental joints.

This all stands orthogonally (literally orthogonally on the two-dimensional semantics picture) to the Kripkean rigidity concerns.

Michael Gonzalez said...

But am I really making a statement about the metaphysics of extension if I just say "a chair should be shaped such that humans of the right size, relative to it, should be able to sit on it?" I mean, at some point, most (if not all) of the descriptions we give for things will be ostensive. A chair looks like *that*, more or less. The fact that it needs to have lots of other properties in order to be that way (extension, wave/particle arrangement, whatever) is really kind of irrelevant. A chair could be made magically out of nothing at all, and it would still be a chair.

But, if there is just the illusion of a chair (as in skeptical scenarios), then there is no chair, and the statement that there is a chair becomes false.

I think part of the issue with your thought experiment is that you are taking for granted that seeing a chair has anything to do with "data"... but then, ALL brain-in-vat scenarios take something like this for granted, which is part of why I find them all completely uncompelling....

Heath White said...


I am not sure, but I think I am less anxious about the "fundamental" part than you.

I can see the utility of having a set of concepts that identifies metaphysically fundamental realities, for purposes of ultimate scientific explanations and so on. But it does not seem to me required that ALL of our concepts share in THIS kind of fundamentality or reducibility to it.

So, for example, I do not think anybody is going to ever define "chair" in terms of fundamental physics. On the other hand, for practical human purposes of sitting down, there is a very serviceable, albeit vague, definition. (Something similar for "berries" and the practical purpose of cooking.) This does not at all seem to me to show that chairs and culinary-berries are "not real" or that we are living in skeptical conditions with respect to them.

(And here I would locate the use of 'form' you seem to be employing--it's a way to shoehorn practical concepts into fundamental concepts, by claiming that forms are metaphysically fundamental. But I just don't feel the need for the shoehorn.)

I think I reason this way ... I am more sure that there are (say) three chairs in my office than I am of any metaphysical theories. So if I have a metaphysical theory that tells me there are no chairs, that is a reductio of the theory, not proof of skepticism about chairs.

Now, the interesting thing about the OP is that (I think) I can imagine skeptical scenarios in which I am wrong about the chairs in my office (the evil demon, the Matrix). But I could also say that, if I learned that one of these scenarios obtained, what I would have found out is that chairs were not what I thought they were. And I am not sure how to draw the line here. I *think* it has something to do with whether I would conclude that the purposes served by my chair-concept would either be (i) frustrated or (ii) worthless if the skeptical scenario were true. For example, if it turned out that chairs were holograms and would not support my weight, that would be frustrating to the whole purpose of identifying chairs. And if I concluded that sitting down was not worth doing any longer, because the whole physical world was an illusion and no physical activity had any point, I might stop saying there were chairs. (I think this is part of what Buddhists mean when they say the world is an illusion.) When neither of these things obtain--which is how Berkeley interpreted his own metaphysics--I am inclined to say that the scenario is not skeptical after all.

(Something to think about: suppose you agree with me that there is a puzzle about whether to say--if Berkeley is right--there are chairs or not. You might settle this by appeal to whether there are FORMS of chairs. But can't we just raise the same question about forms? Suppose forms are just ideas projected from the mind of God we have to ask whether these are real forms or we are in a form-skeptical scenario. That is, we have just moved the bump under the rug from chairs to forms-of-chairs. Reply: hey, you can't do that with forms; skeptical scenarios aren't possible with them. --I think that shows that forms are doing your unexplained-explainer work for you.)

Good puzzle. Lots to think about.


What is the difference between a magical chair made out of nothing at all, and the (very convincing) illusion of a chair?

Alexander R Pruss said...


I don't think one needs forms or fundamentality for everything. Only for enough to bootstrap oneself. Here's a toy example. The legs of a chair are understood analogously to my legs. My legs, let's suppose, have forms. The legs of a chair, let's suppose, do not. But the legs of a chair are, nonetheless, physically similar to my legs: they hold up a weight by means of matter arranged in a columnar fashion. And whatever the fundamental physics -- be it particles, fields or even the universe being a simulation -- it's going to be relevantly similar in the case of my legs and the chair's legs. And that's enough to make true ordinary statements about the chair's legs.

Of course, that's a particularly neat case. But I can generalize it. What counts as matter? The kind of stuff that I am made of (terminology: I have soul, but am made of matter). If I (qua embodied -- not just qua Cartesian soul) fundamentally have a body, that ensures realism about my body. And anything sufficiently similar in physical constitution to my body then counts as material and not illusory.

So I am thinking that a fundamentality in semantically central cases -- say, those of the human body -- will anchor many other cases.

Alexander R Pruss said...

Learning that I am in the Matrix would teach me that my body never sits on a chair--rather, my body is being used in some weird energy-production system. It would also teach me that the visual impressions I have as of hands are not actually visual impressions of hands--my hands are attached to my body, which I never see.

Michael Gonzalez said...

Heath: The difference is that I can sit in an actual chair. It's a real object. That it isn't composed of any smaller pieces seems utterly incidental.

I think "made of nothing at all" is a bit prejudicial, since it sounds like it is unsubstantial or ephemeral. It is a solid chair on which people can sit; it just happens to not be composed of anything more fundamental. I'm not even saying such a thing could exist; merely that we would still regard it as a chair. But illusions aren't objects at all.

Alexander R Pruss said...

Here's a thought I had about the alien's laptop. The thought falls apart, but maybe you have a way of making it work? If our world is simulated inside an alien's laptop, perhaps our "matter" language picks out the alien's world as "material", and hence picks out our world as non-material. Perhaps the physically most fundamental stuff, and the stuff made out of that, is what matter is? And so the alien's body will be matter, while our body won't be matter since it's not *made* out of the physically most fundamental stuff; rather, it's *constituted* by it.

The problem, though, is that one some of the metaphysical renderings of physics, we aren't made out of the physically most fundamental stuff, but only constituted by it. For instance, if the world is a world of global fields, we aren't made of the global fields, but are constituted by them.

Michael Gonzalez said...

I guess my fundamental point (pun intended) is that we are not usually making statements about the composition of a thing when we call it that sort of thing. So, any physical ontology which permits a thing to exist and meet all of our minimum criteria for it to qualify as a chair is acceptable. If we found out it was differently-composed than we had supposed, so what? That would be like finding out it was made of plastic rather than wood. If we found out there is no object there AT ALL, then THAT is significant and alters our worldview.

Interestingly, I think discussions of consciousness and free will often suffer from a failure to understand this same simple point. Just because I say that a human organism can be conscious or can have free will (no non-physical parts required) does NOT mean that I'm explaining either of those phenomena in light of the physical constituents we happen to be composed of. ANY being that was sufficiently like us on the macro scale, and interacted with the world as we do, would be conscious of it. If cells were the smallest bits of matter (replicating and sustaining themselves by magic)), I would still be able to perceive the world and make Libertarian free choices.

The issue isn't composition.

Michael Gonzalez said...

I have no idea what it means to be "constituted" of matter, but not made of it....

Alexander R Pruss said...

The shape of a rock is constituted by the matter, but isn't made of matter. If it were made of matter, it would make sense to ask how much the shape of the rock weighs, what color it is, etc.

Money is constituted by social convention, but isn't made of it.

Heath White said...


So, my first thought is that 'matter' has a well-defined theoretical role in Aristotelian physics but not such a well-defined role in modern physics and maybe no role at all. We can use 'matter' to mean "the most fundamental physical stuff" but that assumes (a) there is a most fundamental layer, and (b) it's *stuff*, not e.g. fields. So one cannot assume that "the most fundamental physical stuff" has a referent.

But if those assumptions hold, and we decide to use 'matter' with that definition, then it would follow that the alien turns out to be made of matter and we do not. That would be remarkable.

On the other hand we could decide to use 'matter' to mean something like "the occupant of the theoretical role of most fundamental stuff for the theory that presents itself to our apparent reality." Then we turn out to be made of matter and (I guess) the alien does not. But in this case it is remarkable that apparent reality is not much like real reality.

So my point is that if we find out that we are running on an alien's laptop, we have found out something remarkable in either case. There is a "skeptical" reading on which we learn that we are not made out of matter, and a "reductionist" reading on which we learn that matter is not fundamental. But it seems to me that this is something of a choice, and maybe we can describe the situation either way.

Anonymous said...

What counts as a skeptical scenario? In the post, you seem to define it as something that implies that Aristotelian philosophy is false. But that can't be right: a skeptical scenario should be one in which common sense is false. Whether your philosophy is true or false should be secondary. And that is true even if you think your philosophy is just a thinking through of common sense.

Certainly according to common sense I have two hands. And I think situations that imply that I do not currently have two hands are skeptical scenarios.

Consider the brain in a vat scenario. By the reasoning in the first part of the post, you could say that the scenario does not imply that I do not have two hands, and therefore it is not a skeptical scenario.

There is a problem, however. According to common sense, a brain is not a human body and does not have hands. And if I am a brain in a vat, then I am a brain. And that means I do not have two hands. And so the situation is skeptical after all.

But if we stop to think about it, we can easily see the problem. "I am a brain in vat," formulated just like that, is indeed a scenario that implies that common sense is false. And since I do know that I have two hands, I know that I am not a brain in a vat. However, there is a different situation, and I do not know that I am not in it. It is this: "I am something analagous to a brain in something analagous to a vat." Obviously, if I am in such a thing, or if I in a computer simulation, or whatever, then just as the words "hands" refer to something in the brain or simulation or whatever, so the words "brain" and "vat" refer to something in the same situation. So the sentence "I am a brain in a vat" is still false, just as it is still false that "I do not have two hands."

But the new formulation, "I am something analagous to a brain in something analagous to a vat," escapes that difficulty. But it is not a skeptical scenario, since it does not imply that common sense is false.

I am not sure about the rest of your argument about reductionism and forms and so on. In particular, I am not yet clear on the distinction between a reductionist position and an anti-reductionist one. Does the reductionist say, "nothing exists except fundamental things. Nothing can be made out of fundamental particles, since it would be something other than a fundamental particle, and there can be nothing except fundamental things?"

If the reductionist asserts this, it is clearly false and opposed to common sense, since it means that "I have two hands" is false, because a hand is not a fundamental particle. If anti-reductionism simply means the above reductionism is false, it does not seem necessary to say that it requires an Aristotelian account of forms and so on, but just "more than fundamental particles exist, since hands and chairs and tables and so on also exist."

Alexander R Pruss said...

I agree that it is very hard to formulate the question.

But I think we can think through some of these things by use of analogy and a reference / attribution distinction. Whether or not we are brains in vats, there is an aspect of reality that I manage to refer to when I say "My right hand is open", just as in Donnellan's example there is a person one manages to refer to when one says "The man drinking champagne in the corner is a senator", whether or not it is champagne or ginger-ale that the senator is drinking. The question, however, is whether it is correct to attribute being a hand or drinking champagne to the objects in question.

Now consider the simulated-by relation between virtual reality and a computer. This relation can be nested. If I run a Mac emulator on my PC, and I run a ZX81 emulator on the emulated Mac, the ZX81 stands in the simulated-by relation to the Mac, and the Mac stands in the simulated-by relation to the PC. Notice that the concept of the simulated-by relation does not depend on any thick concept of "unsimulated reality". Intuitively, the PC is real and the Mac and ZX81 are virtual, but it doesn't matter for the simulated-by relation. If the PC were itself a simulation, it would still be true that the ZX81 is simulated by the Mac and the Mac by the PC.

We can easily grasp the simulated-by relation. So now I can meaningfully ask the question: Does the aspect of reality I refer to by the phrase "my right hand" stand in a simulated-by relation to anything?

Now note an important point: There is a difference between reference and attribution. Attributive failure is not referential failure. The person who sees me from a distance and thinks I am a woman and says "That woman is probably a graduate student" is making a mistake about *me*, and hence is succeeding in referring to me, even though I am neither a woman nor a graduate student. (There is a further Donnellan question whether her sentence would be true if I were a graduate student but not a woman. But I don't need a resolution to that.) Likewise, then, when I say "My right hand is dominant", I am succeeding in referring to an aspect of reality whether or not I have any hands (unless I am completely delusional).

And so it makes sense to ask whether the referent of "my right hand" is simulated or not. This is a perfectly meaningful question.

And there is a second question. Suppose that the referent of "my right hand" is a simulated thing. Then is that referent a hand? I think the answer to that question is negative. It's only instrumentally bad for me to lose a simulated "hand" (scare quotes are a nice way to indicate purely referential use), but it's non-instrumentally bad for me to lose a hand. Furthermore, a simulated "hand" is not a part of an individual but a hand is.

But I could see someone disagreeing, and holding that even if the referent is something simulated, it could still be a hand. In that case, our normative view that it's intrinsically bad to lose a hand is incorrect.

We now have something like a concept of the "real". A necessary condition for being real is not being simulated by anything. A real ZX81 isn't simulated by a Mac or a PC or anything else.

A sceptical hypothesis is a hypothesis that common-sense things aren't real. Interestingly, this means that you could in principle believe a sceptical hypothesis about your hands even though you think you have two hands, though you would have to revise some normative and metaphysical views.

In this terminology we can put the question of the post as follows: Why is it that the necessary conditions for being real rule out being simulated but do not rule out the various physics hypotheses?

Michael Gonzalez said...

Pruss: Shapes and monetary value are not things. We are. So the alien laptop scenario has a pretty glaring hole in the middle of it, if it entails that we are not things.... I wonder if some QM interpretations have the same problem....

To answer your overall question, there is a good chance that some of the physics hypotheses do indeed suffer the same fatal flaw that simulation/brain-in-vat scenarios have, and therefore should be abandoned. Too bad the zeitgeist is currently to think that the barest whisper from a scientist drowns out the loudest shouts from an entire faculty of philosophers.

Michael Gonzalez said...

entirelyuseless makes an entirely useful point: We are manifestly not brains in vats, but could be we be something analogous to a brain in something analogous to a vat in the relevant senses? My answer is resolutely "no", since only things which are sufficiently similar to animals, in settings where they engage with objects sufficiently similar to the real world objects, could actually be conscious at all.

In any case, simulations convey things to outside observers only. You cannot be a part of the simulation and yet observe it. That would be meaningless.

Heath White said...


Your last comment was definitely very helpful. I think I am different from you in questioning the clarity of the “simulated by” relation. In particular, how is “X is simulated by Y” different from “X is composed of [parts of] Y.” My worry is that if, say, phenomenalism were true, I am not sure whether sense data would compose my hands (which is what phenomenalists want to say) or merely simulate them (the skeptical interpretation).

This matters because you endorse

If X is real then X is not simulated by anything

which I can see the sense of, but I would strenuously deny (would you?)

If X is real then X is not composed of anything.

Question: does my PC run a real calculator or a simulated one? The case for simulated: we know what a real calculator looks like, this is just imitating that in a computer program. The case for real: a calculator is nothing but (is essentially) its function; its realization is irrelevant. The difference between these views seems to be over whether a real calculator is essentially embodied in hardware.

Corollary: If we thought Macs were essentially embodied in hardware—not unreasonable, because ‘Mac’ seems to refer to the hardware instruction set rather than the operating system or anything else— that would explain why a PC emulating a Mac was not a real Mac, as what does the emulation is software rather than hardware.

Corollary: If we thought human beings, or human hands, were essentially embodied, i.e. their "realization" is not irrelevant, then that would explain why we might think running on an alien laptop, or being composed of sense data, was not a case of a real human being but only a simulated one.

Suggestion: those who think human beings are essentially defined in terms of their mental or psychological attributes—Lockeans about personal identity, Cartesians about egos (maybe), those who emphasize our projects or purposes or values as what is really important about us, etc.—are going to think that existing on an alien laptop is a case of composition, not simulation, so we can still be real. Those who think of us as essentially embodied, e.g. animalists and Aristotelians, will think of the alien laptop case as mere simulation and not real.

Alexander R Pruss said...

I would think that the calculator program on my laptop isn't a calculator. However, the laptop qua equipped with the calculator program is a calculator (as well as being a word-processor, a communications device, etc.)

On the other hand, on my phone I have an emulator of a TI-89 calculator. I think my phone is a calculator, indeed in virtue of that emulator. But my phone is not a *TI-89* calculator, and the "TI-89" that is running on the phone is simulated by the phone.

Likewise, my Windows laptop isn't a Mac laptop. That has legal considerations. I have MacOS 7.5.3 installed in an emulator (or at least did--I am not sure it's on right now), with MacOS legally downloaded from the Apple ftp server. But I cannot legally run any version of MacOS later than 7.5.5 because the EULA for MacOS 7.6 and higher only licenses the OS for Apple-branded hardware. But a Mac is Apple-branded hardware.

I think it's incorrect to say that if x is simulated by y, then x is composed of parts of y. It seems to be a category mistake to say that, say, a Minecraft house has a computer chip or a physical piece of a hard drive as a part of it. Rather, x is constituted by y or its parts. (Composition may be a special case of constitution.) I am not sure this affects any of your points.

If I learned that I live fully in a computer simulation, I would definitely say that *I* am real. But I am a firm dualist: being minded requires something like a soul. So I couldn't be *wholly* constituted by the computer simulation, just as I couldn't be wholly constituted by particles, or fields, or anything like that.

What about my body? I think it would depend on what the metaphysics turned out to be like. I think there are two possible stories.

First, my metaphysics could be Cartesian. In that case, I would just *be* an immaterial soul, and I think my virtual body wouldn't be real. I would be an angel who gets input from a computer.

Second, my metaphysics could be Aristotelian. In that case, my form (=my soul) could perhaps inform aspects of the computer. If it did that, it could form aspects of the computer into a real body, with a heart, lungs, etc., albeit differently constituted ones from the ones we think we have. In such a case, I could have a real body.

If I learned that I am living as a brain in a vat being fed sensory data by a computer, I would say:
1. I am real.
2. I have a real body and an unreal body. My real body consists solely of a brain. My unreal body consists of various unreal things like unreal hands, unreal legs, unreal heart, unreal brain, etc.

If I learned that my situation was as in the Matrix, I would say:
1. I am real.
2. I have a real body and an unreal body. My real body is lying somewhere and energy is being collected from it. It has a brain, hands, legs, heart, etc. My unreal body is moving through the virtual world, and has an unreal organs.

Anonymous said...

This question might not be totally relevant to the thread, but what exactly do you know about particles or fields or whatever that would prevent them from wholly constituting you? It seems like the only difference between immaterial and material things that we can be sure of is that material things are quantitative. But you have said yourself that the quantity of particles might not be fundamental, in which case how can we even distinguish between the soul and the body? Is it just that there is one part which is more important than any of the other parts?

I think I understand the point about simulating. The idea is that if something is simulated, it is not there to do anything, but the thing which is simulating does what that thing would normally do. Which means that if my arm is simulated, I do not have an arm, since it is not an arm doing those things, but something else.

But then someone could say that my arm is something simulated by something else, but that it is not a simulated arm, but a real one, because "to be an arm" in our world is to be the simulation of something (that is, of something other than an arm.) In terms of my analogy before, if I am something analagous to a brain in something analagous to a vat, my arm is a real arm, but it is a simulation of something analagous to an arm. I don't see how your argument can refute this, and I don't see any reason to call the scenario skeptical, rather than just saying that if that were true, there would be parts of reality which we don't currently know. Which is the case anyway.

Heath White said...

I think I can see the motivation for that set of views. They have the consequence that computer programs aren't real. But neither are they simulated. What do you want to say of them... are they properties of computers?

In that case, is it possible that I (or my body) am a property and not a substance?

Alexander R Pruss said...

The best theory of mind on which I'm wholly constituted by particles or fields is functionalism. And functionalism fails, except in an Aristotelian setting, and that probably requires forms.

Anonymous said...

"And functionalism fails, except in an Aristotelian setting, and that probably requires forms."

That may be right but having a form isn't the same as dualism since presumably you would not be a dualist about rocks or bananas, but those things would still have forms.

I think something like functionalism together with forms may be true, in this sense: according to St. Thomas, on account of God's "benevolence," every disposed matter receives the form to which it is disposed. And it seems to me that something that is disposed to behave in a rational way is disposed to be a rational being, and therefore it will have the corresponding form.

It is just not clear to me how you can get from that to dualism. I have seen the arguments. The problem, it seems to me, is that matter is virtually unknown to us, and in order to get dualism, we need to know something about matter that makes it especially incapable of receiving a rational form in the way it receives other forms (unless you are going to be dualist about everything.) I don't know what that could be, or how you could know it was true about matter.

Michael Gonzalez said...

I'm completely ignorant here, but I'm curious: Is the following view "functionalist"? If so, does it require "forms"?

Perception and consciousness are capacities of particular sorts of organisms. We engage with objects in the world in particular skillful ways which bring them into focus for us. This set of capacities is built on top of our already distinctive "nutritive psyche". The higher functions are capacities built a further step up and they are heavily predicated on being language-using creatures.

This is the roughest, barest sketch I could manage of my view on consciousness, but I'm just curious whether it is considered "functionalist" and why it would require the addition of "forms"....

Michael Gonzalez said...

The "nutritive psyche" part is just to indicate what makes living creatures distinct from non-living objects. I only brought it up because it means we are already engaging with the world in a dynamic way, and then our consciousness of it is built on top of that with particular sorts of skillful interactions.

Alexander R Pruss said...


I am a dualist about oak trees in exactly the same sense that I am a dualist about people: each has to have a form. I do not, however, think that rocks have forms. I suppose a banana attached to a banana plant has an accidental form qua part of the banana plant, but a detached banana fruit is not an organism or a part thereof, and probably lacks form. However, the seeds in the banana, if there are any, do have form, as they are tiny banana plants, I think.

The forms of people induce causal powers that the forms of oak trees do not--they induce the power of thought. On the other hand, the forms of oak trees induce causal powers that the forms of people do not--say, the power to photosynthesize.

Michael Gonzalez said...

But what explanatory work is "form" doing in those examples (banana seeds; humans; etc)?