Shape and parts

Alice is a two-dimensional object. Suppose Alice’s simple parts fill a round region of space. Then Alice is round, right?

Perhaps not! Imagine that Alice started out as an extended simple in the shape of a solid square and inside the space occupied by her there was an extended simple, Barbara, in the shape of a circle. (This requires there to be two things in the same place: that’s not a serious difficulty.) But now suppose that Alice metaphysically ingested Barbara, i.e., a parthood relation came into existence between Barbara and Alice, but without any other changes in Alice or Barbara.

Now Alice has one simple part, Barbara (or a descendant of Barbara, if objects “lose their identity” upon becoming parts—but for simplicity, I will just call that part Barbara), who is circular. So, Alice’s simple parts fill a circular region of space. But Alice is square: the total region occupied by her is a square. So, it is possible to have one’s simple parts fill a circular region of space without being circular.

It is tempting to say that Alice has two simple parts: a smaller circular one and a larger square one that encompasses the circular one. But that is mistaken. For where would the “larger square part” come from? Alice had no proper parts, being an extended simple, before ingesting Barbara, and the only part she acquired was Barbara.

Maybe the way to describe the story is this: Alice is square directly, in her own right. But she is circular in respect of her proper parts. Maybe Alice is the closest we can have to a square circle?
Here is another apparent possibility. Imagine that Alice started as an immaterial object with no shape. But she acquired a circular part, and came to be circular in respect of her proper parts. So, now, Alice is circular in respect of her proper parts, but has no shape directly, in her own right.

Once these distinctions have been made, we can ask this interesting question:

• Do we human beings have shape directly or merely in respect of our proper parts?

If the answer is “merely in respect of our proper parts”, that would suggest a view on which we are both immaterial and material, a kind of Hegelian synthesis of materialism and simple dualism.

Nitpicking about the causal exclusion argument

Exclusion arguments against dualism, and sometimes against nonreductive physicalism, go something like this.

1. Every physical effect has a sufficient microphysical cause.

2. Some microphysical effects have non-overdetermined mental causes.

3. If an event E has two distinct causes A and B, with A sufficient, it is overdetermined.

4. So, some mental causes are identical to microphysical causes.

But (3) is just false as it stands. It neglects such cases of non-overdetermining distinct causes A and B as:

5. A is a sufficient cause of E and B is a proper part of A, or vice versa. (Example: E=window breaking; A=rock hitting window; B=front three quarters of rock hitting window.)

6. A is a sufficient cause of B and B is a sufficient cause of E, or vice versa, with these instances of sufficient causation being transitive. (Example: E=window breaking; A=Jones throwing rock at window; B=rock impacting window.)

7. B is an insufficient cause of A and A is a sufficient cause of B, with these instances of causation being transitive. (Example: E=window breaking; B=Jones throwing rock in general direction of window; A=rock impacting window.)

8. A and B are distinct fine-grained events which correspond to one coarse-grained event.

To take care of (6) and (7), we could replace “cause” with “immediate cause” in the argument. This would require the rejection of causation by a dense sequence of causes (e.g., the state of a Newtonian system at 3 pm is caused by its state at 2:30 pm, its state at 2:45 pm, at 2:52.5 pm, and so on, with no “immediate” cause). I defend such a rejection in my infinity book. But the price of taking on board the arguments in my infinity book is that one then has very good reason to accept the Kalaam argument, and hence to deny (1) (since the first physical state will then have a divine, and hence non-microphysical, cause).

We could take care of (5) and (8) by replacing “distinct” with “non-overlapping” in (3). But then the conclusion of the argument becomes much weaker, namely that some mental causes overlap microphysical causes. And that’s something that both the nonreductive physicalist and hylomorphic dualist can accept for different reasons: the nonreductive physicalist may hold that mental causes totally overlap with microphysical causes; the hylomorphist will say that the form is a part of both the mental cause and of the microphysical cause. Maybe we still have an argument against substance dualism, though.

Another way out of the closure argument

Consider this standard closure of the physical argument for physicalism (Papineau gives one very close to this):

1. Our conscious states have physical effects.

2. All physical effects are fully caused by physical causes.

3. There is (typically) no overdetermination.

4. So, our conscious states are (at least typically) physical.

Many dualists question (2), and epiphenomenalists question (1). But there is another move that seems to me to be promising.

When we say that our conscious states have physical effects, we don’t mean that our conscious states are the full causes of physical effects. Descartes himself would say that the movements of the particles in the pineal gland are partly caused by the conscious choice and partly caused by the prior state of the particles.

In other words, (1) just tells us that our conscious states are partial causes of physical effects. Given this, what (1)–(3) license us in concluding is only:

5. Our conscious states are (at least typically) parts of physical causes.

But to conclude from (5) that our conscious states are physical, it seems we need some premise like:

6. All the parts of physical things are physical.

But (6) is worth questioning. Note first that it is easier to find false than true cases of principles like:

7. All the parts of Fs are Fs

(E.g., electrons are parts of red things, but electrons aren’t red.) So why think (6) is true?

So, it seems that (6) needs some argument.

And in fact there are serious metaphysical views on which (6) is false. Consider, for instance, bundle theory: substances are bundles of properties. Well, rocks are physical objects, but a part of the bundle that makes up a rock will be the abstract entity of rockiness. But abstract entities aren’t physical.

Or take a reading (perhaps a misreading) of Leibniz on which physical objects are constituted by non-physical monads, and suppose that constituents count as parts.

Or, most promisingly, take Aristotle’s view on which all physical objects have form. Form is immaterial, and plausibly non-physical. Hylomorphism thus escapes the closure argument.

More generally, for all we know, the fundamental structure of reality is such that physically fundamental things are not ontologically fundamental but themselves have parts that are not physical.

Computer consciousness and dualism

Would building and running a sufficiently “smart” computer produce consciousness?

Suppose that one is impressed by the arguments for dualism, whether of the hylomorphic or Cartesian variety. Then one will think that a mere computer couldn’t be conscious. But that doesn’t settle the consciousness question. For, perhaps, if one built and ran a sufficiently “smart” computer (i.e., one with sufficient information processing capacity for consciousness), a soul would come into being. It wouldn’t be a mere computer any more.

Basically the thought here supposes that something like the following is a law of nature or a non-coincidental regularity in divine soul-creation practice:

1. When matter comes to be arranged in a way that could engage in the kind of information processing that is involved in consciousness, a soul comes into existence.

Interestingly, though, a contemporary hylomorphist has very good reason to deny (1). The contemporary
hylomorphist thinks that the soul of an animal comes into existence at the beginning of the animal’s existence as an animal. Now consider a higher animal, say Rover. When Rover comes into existence as an animal out of a sperm and an egg, its matter is not arranged in a way capable of supporting the kind of information processing involved in consciousness. Yet that is when it acquires its soul. When finally the embryo grows a brain capable of this kind of information processing, no second soul comes into existence and hence (1) is false. (I am talking here of contemporary hylomorphists; Aristotle and Aquinas both believed in delayed ensoulement which would complicated the argument, and perhaps even undercut it.) The same argument will apply to those Cartesian dualists who are willing to admit that they were once embryos without brains.

Perhaps one could modify (1) to:

2. When matter comes to be arranged in a way that could engage in the kind of information processing that is involved in consciousness and a soul has not already come into existence, then a soul comes into existence.

But notice now two things. First, (2) sounds ad hoc. Second, we lack inductive evidence for (2). We know of no cases where the antecedent of (2) is true. If we were to generate a computer with the right kind of information processing capabilities, we would know that the antecedent of (2) is true, but we would have no idea if the consequent is true. Third, our observations of the world so far all fit with the following generalization:

3. Among material things, consciousness only occurs in living things.

But a “smart” computer would still not be likely to be a living thing. If it were, we would expect there to be non-“smart” computers that are alive, by analogy to how just as there are conscious living things, there are unconscious ones. But it is not plausible that there would be computers that are alive but not “smart” enough to be conscious. One might as well think that the laptop I am writing this on will be conscious.

This isn’t a definitive refutation of (2). God has the power to (speaking loosely) provide an appropriately complex computer with a soul that gives rise to consciousness. But inductive generalization from how the world is so far gives us little reason to think he would.

Informed organs surviving the death of an individual

In my last post, I offered a puzzle, one way out of which was to accept the possibility of informed bits of an animal surviving the death of the animal. But the puzzle involved a contrived case--a snake that was annihilated.

But I can do the same story in a much more ordinary context. Jones is lying on his back in bed, legs stretched out, with healthy feet, and dies of some brain or heart problem. How does the form (=soul) leave his body? Well, there are many stories we can tell. But here's one thing that's clear: the form does not leave the toes before leaving the rest of the body. I.e., either the toes die (=are abandoned by the form) last or they die simultaneously with the rest. But in either case, then Special Relativity and the geometry of the body (the fact that one can draw a plane such that one or more toes are on one side of the plane, and the rest of the body is on the other) imply that there is a reference frame in which the form leaves one or more of the toes last. Thus, there will be a reference frame and a time at which only toes or parts of toes are informed. It is implausible to think that one is alive if all that's left alive are the toes. So organs can survive death while informed by the individual's form.

Snake annihilation and partial death

The following five principles seem to be rationally incompatible:

1. Every part of a living organism is informed by its form.

2. If any part of an organism is informed by its form, the organism is alive.

3. An snake would be dead if everything but the tailmost one percent of its length were annihilated.

4. Simultaneity is relative, as described by Special Relativity.

5. Being informed by a form is not relative to a reference frame.

To see the incompatibility, consider this case. A snake of ordinary proportions is lying stretched out in a line and is then instantaneously completely annihilated. Notice an interesting fact about this snake:

6. Every bit of this snake is informed by the form of the snake whenever it exists.

This follows from (1) and the setup of the situation. Note that (6) will not be true in the case of snakes that meet a more ordinary end than by complete instant annihilation: those snakes leave behind parts that are no longer informed (they may be parts only in a manner of speaking, but I think nothing in my argument hangs on this). It is to make (6) true that I supposed the snake annihilated instantaneously.

Now, by (4), the claim that the snake is must have been said with respect to some reference frame F₁. But it follows from Special Relativity and the geometry of linear snakes that there will be a reference frame F₂ relative to which the snake is annihilated gradually from the head to the tail rather than simultaneously. There will thus be a time t₂ such that relative to F₂ at t₂ the snake has been annihilated except for the tailmost one percent. At t₂ relative to F₂, that tailmost one percent is informed by the form of the snake by (5) and (6). By (2), the snake is alive at t₂ relative to F₂. But by (3), it is dead at t₂ relative to F₂. So, the snake is both alive and dead at t₂ relative to F₂, which is absurd.

I am not sure what to do about this argument. I feel pushed to deny (2). Perhaps something could be dead simpliciter but still have living parts. But that’s an uncomfortble position.

Immaterial body parts

Here’s a difficult question: Does an artificial heart literally become a body part of the patient?

And here’s a line of thought suggestive of a negative answer.

1. Necessarily, all our body parts are material.

2. If one could have an artificial heart as a body part, one could have an immaterial artificial heart as a body part.

3. So, one cannot have an artificial heart as a body part.

Why accept 2? Because presumably what makes an artificial heart suitable for being a body part is that it does the job of a heart. But we could imagine an immaterial being which does the job of a heart. For instance, an angel could move blood around the body, and do so in response to electrical activity in the brain stem. Perhaps one could say that an angel couldn't be a body part, because it is already an intelligent being. But we could then imagine something that moves blood around like the angel but doesn’t have a mind.

I am not so confident of premise 1, however. One could, I suppose, turn the argument around: An artificial heart could be a body part, so possibly some of our body parts are immaterial. And if that’s right, then given a view on which body parts are informed by the form of the person, we would have the further interesting conclusion that a form can inform something that isn’t matter.

Particles

I used to worry for Aristotelian reasons about the particles making up my body. The worry went something like this: Elementary particles are fundamental entities. Fundamental entities are substances. But no substance has substances as parts. The last is, of course, a very controversial bit. However there are good Aristotelian reasons for it.

But I shouldn't have worried much. Elementary particles are not all that likely to be fundamental entities. Quantum mechanics, after all, allows all sorts of superpositions between different particles. But substances either simply exist or simply don't. In the superposition case, they don't simply exist. So they simply don't. But I would expect that the superposition case is more the rule than the exception (if only with small coefficients for all but one one state). I guess we could think that when the wavefunction is in a pure state with respect to the existence of a particle, the particle then pops into existence, and when the state becomes mixed, it pops right out. But notice that the physics behaves in much the same way when we have a pure state and when we have a mixed state that is to a very high approximation pure. So whatever explanatory role the particles play when they pop into existence can be played, it seems, by the wavefunction itself when the particles aren't around. This suggests that the wavefunction is the more explanatorily fundamental entity, not the particles. Of course, the above relies on denying the Bohmian interpretation of quantum mechanics. But it's enough, nonetheless, to establish that elementary particles aren't all that likely to be fundamental entities. And hence they aren't all that likely to be substances.

Of course, it may be that the things that are fundamental physical entities will turn out to be just as problematic for the Aristotelian as the particles were...

An argument against materialism and composite substance dualism

Let composite substance dualism be the doctrine that I am composed of two distinct substances: my soul and my body. I find compelling the following argument, though I think my opponents will simply deny premise 1.

1. I am only agentially responsible for an event E if I non-derivatively cause E.
2. If composite substance dualism is true, everything I cause is caused by me derivatively from causation by my soul and I am not my soul.
3. If materialism is true, everything I cause is caused by me derivatively from causation by proper parts of me (e.g., particles, neurons) and/or things outside of me (e.g., fields).
4. So, if materialism or composite substance dualism is true, I am not agentially responsible for any event.
5. But there are events are I am agentially responsible for.
6. So, composite substance dualism and materialism are false.

An argument against physicalism in biology

1. (Premise) Every biologically significant purely physical event happens at the same time as a chemically significant purely physical event.
2. (Premise) No chemically significant purely physical event takes less than 10⁻²² seconds (it takes 1.7x10⁻²⁰ seconds for light to cross the Bohr radius of the hydrogen atom).
3. (Premise) The coming into existence of an animal is a biologically significant event.
4. (Premise) There is no vague existence at a time.
5. (Premise) If there is no vague existence at a time, transitions between non-existence and existence are instantaneous.
6. (Premise) Instantaneous events take less than 10⁻²² seconds.
7. Transitions between existence and non-existence do not happen at the same time as a chemically significant purely physical event. (2, 4, 5 and 6)
8. If the coming into existence of an animal is a purely physical event, it happens at the same time as a chemically significant purely physical event. (1 and 3)
9. The coming into existence of an animal is not a purely physical event. (7 and 8)

Vagueness about existence of substances

I suspect that pressure to believe in vagueness about the existence of material substances comes from a belief that facts about the existence of material substances supervene on facts about the physical arrangement of matter in the universe. The most plausible arguments for such vagueness is questions like this: What time t₀ in the history of the union of the gametes of Bambi's parents is such that were the world annihilated at t, Bambi would not have existed? Given that the union of gametes is a physically continuous process, there seems to be an interval of time (perhaps several hours long) such that drawing a line at a particular point of that interval and asserting that it is precisely at that time that Bambi came into existence seems arbitrary.

But if one does not believe that facts about when Bambi came into existence supervene on facts about the physical arrangement of matter in Bambi's history, then an epistemic solution on which some particular point in that interval that we cannot scientifically determine exactly has the property of being such that Bambi came into existence precisely at that point is not that implausible. The fact that points slightly before and slightly t₀ would seem to be just as physically fitting for Bambi's existence is irrelevant, since Bambi's existence does not supervene on whether there is a physical state fitted out for Bambi's existence. Compare the fact that when an atom decays at t₀, it could just as easily have decayed shortly before t₀ or shortly after t₀—there is a real sense in which its decaying at t₀ rather than shortly before or after (or maybe even a long time before or after) was arbitrary (unless Providence has some special reason for t₀, which quite possibly it does). That doesn't trouble us that much, I suspect because we accept that when the atom decays is contingent. Well, likewise, if we accept that even given all the physical facts, it is contingent when Bambi comes into existence, we shouldn't be worried about the fact that nearby times are such that they would have done just as well as far as we can tell (though Providence might have some special reason for choosing one time rather than another).

The same issue comes up with regard to those like Trenton Merricks who believe in limited composition theories: some bunches of things compose a whole but not all bunches of things compose wholes. There seems to be vagueness as to composition. We can imagine a continuous sequence of hypothetical biological/physical situations, starting with what are clearly two trees and ending with what is clearly one tree (with in-between cases which, depending on whom you ask, look like two trees grown together or one tree with a bit of a divide down its trunk). It seems arbitrary to suppose that at some point in the sequence we have one tree, and very shortly before in that sequence we had two. But again, this intuition depends on a supervenience claim: the supervenience of facts about composition on facts about physical arrangement of matter. Granted such supervenience, we do seem to get arbitrariness. But why not, instead, deny supervenience, and simply say that what we get is contingency: given given a particular biological/physical arrangement of matter, there is a contingent fact whether all this matter composes a whole or not.

Of course one might worry about the Principle of Sufficient Reason (PSR) here. But if we believe in quantum mechanics (QM), then presumably we either think the PSR is compatible with QM or we deny the PSR. If we deny the PSR, then the problem that the story I gave is alleged to be incompatible with the PSR shouldn't worry us. But if we think that the PSR is compatible with QM, then I suspect that whatever story we give about the compatibility of QM and the PSR will also have an analogue here. (I defend the compatibility of QM and the PSR in my book on the PSR.) For instance, if we say that God providently chooses which otherwise random results of a quantum experiment will happen, then we can say the same here: God providently chooses when exactly Bambi comes into existence and whether there is one tree or a pair of trees. Or if we say that effects caused stochastically under probabilistic laws are not violations of the PSR, then we can say that there are probabilistic laws about the arising of substances or about composition.