One-thinker colocationism

Colocationists about human beings think that in my chair are two colocated entities: a human person and a human animal. Both of them are made of the same stuff, both of them exhibit the same physical movements, etc.

The standard argument against colocationism is the two thinkers argument. Higher animals, like chimpanzees and dogs, think. The brain of a human animal is more sophisticated than that of a chimpanzee or a dog, and hence human animals also have what it takes to think. Thus, they think. But human persons obviously think. So there are two thinkers in my chair, which is innately absurd, plus leads to some other difficulties.

If I were a colocationist, I think I would deny that any animals think. Instead, the same kind of duplication that happens in the human case happens for all the higher animals. In my chair there is a human animal and a person, and only the person thinks. In the doghouse, there is a dog and a “derson”. In the savanna, one may have a chimpanzee and a “chimperson”. The derson and the chimperson are not persons (the chimperson comes closer than the derson does), but all three think, while their colocated animals do not. We might even suppose that the person, the derson and chimperson are all members of some further kind, thinker.

Suppose one’s reason for accepting colocationism about humans is intuitions about the psychological components of personal identity: if one’s psychological states were transfered into a different head, one would go with the psychological states, while the animal would stay behind, so one isn’t an animal. Then I think one should say a similar thing about other higher animals. If we think that that an interpersonal relationship should follow the psychological states rather than the body of the person, we should think similarly about a relationship with one’s pet: if one’s pet’s psychological states are transfered into a different body, our concerns should follow. If Rover is having a vivid dream of chasing a ball, and we transfer Rover’s psychological states into the body of another dog, Rover would continue the dream in that other body. I don’t believe this in the human case, and I don’t believe it in the dog case, but if I believed this in the human case, I’d believe it in the dog case.

What are the reasons for the standard colocationist’s holding that the human animal thinks? One may say that because both the animal and the person have the same brain activity, that’s a reason to say that either both or neither thinks. But the brain also has the same brain activity, and so if this is one’s reason for saying that the animal thinks, we now have three thinkers. And, if there are unrestricted fusions, the mereological sum of the person with their clothes also has the same brain activity, thereby generating a fourth thinker. That’s absurd. Thus thought isn’t just a function of hosting brain activity, but hosting brain activity in a certain kind of context. And why can’t this context be partly characterized by modal characteristics, so that although both the animal and the person have the same brain activity, they provide a different modally characterized context for the brain activity, in such a way that only one of the two thinks?

This one-thinker colocationism can be either naturalistic or dualistic. On the dualistic version, we might suppose that the nonphysical mental properties belong to only one member of the pair of associated beings. On the naturalistic version, we might suppose that what it is to have a mental property is to have a physical property in a host with appropriate modal properties—the ones the person, the derson and the chimperson all have.

I think there is one big reason why a colocationist may be suspicious of this view. Ethologists sometimes explain animal behavior in terms of what the animal knows, is planning, and more generally is thinking. These explanations are all incorrect on the view in question. But the one-thinker co-locationist has two potential answers to this. The first is to weaken her view and allow animals to think, but not consciously. It is only the associated non-animal that has conscious states, that has qualia. But the conscious states need not enter into behavioral explanations. The second is to say that the scientists’ explanations while incorrect can be easily corrected by replacing mental properties with their neural correlates.

Sameness without identity

Mike Rea’s numerical-sameness-without-identity solution to the problem of material constitution holds that the statue and the lump have numerical sameness but do not have identity. Rea explicitly says that numerical sameness implies sharing of all parts but not identity.

Does Rea here mean: sharing of all parts, proper or improper? It had better not be so. For improper parthood is transitive.

Proposition. If improper parthood is transitive and x and y share all their parts (proper and improper), then x = y.

Proof: But suppose that x and y share all parts. Then since x is a part of x, x is a part of y, and since y is a part of y, y is a part of x. Moreover, if x ≠ y, then x is a proper part of y and y is a proper part of x. Hence by transitivity, x would be a proper part of x, which is absurd, so we cannot have x ≠ y. □

So let’s assume charitably that Rea means the sharing of all proper parts. This is perhaps coherent, but it doesn’t allow Rea to preserve common sense in Tibbles/Tib cases. Suppose Tibbles the cat loses everything below the neck and becomes reduced to a head in a life support unit. Call the head “Head”. Then Head is a proper part of Tibbles. The two are not identical: the modal properties of heads and cats are different. (Cats can have normal tails; heads can’t.) This is precisely the kind of case where Rea’s sameness without identity mechanism should apply, so that Head and Tibbles are numerically the same without identity. But Tibbles has Head as a proper part and Head does not have Head as a proper part. But that means Tibbles and Head do not share all their proper parts.

Here may be what Rea should say: if x and y are numerically the same, then any part of the one is numerically the same as a part of the other. This does, however, have the cost that the sharing-of-parts condition now cannot be understood by someone who doesn’t already understand sameness without identity.

Self-colocation

Self-colocation is weird. An easy way to generate it is with time travel. You take a ghost or other aethereal object who time travels to meet his past self, and then walks into the space occupied by his past self--ghosts can walk into space occupied by themselves--so that he is exactly colocated with himself. If you don't like ghosts, time travel a photon--or any other boson--into the past and make it occupy the same place as itself. But time travel is controversial.

However, it occurs to me that one can get something a bit like self-colocation with an aethereal snake and no time travel. An aetherial snake can overlap itself. First, arrange the snake in spiral with two loops. Then gradually tighten the ring, so that the outer ring of the spiral overlaps the inner one, until the result looks like a single ring. Suppose that the snake exhibits no variation in cross-section. So we have a snake that is wound twice in the same volume of space. The whole snake occupies the same region as two proper parts of itself. [I'm not the only person in this room generating odd examples: Precisely as I write this, I hear our four-year-old remarking out of the blue that she wished she had two bodies, so she could be in two places at once. A minute or so later she is talking of twenty bodies.]

(The animation was generated with OpenSCAD using this simple code.)

So far it's not hard to describe this setup metaphysically: the whole overlaps two proper parts. But now imagine that our snake ghost is an extended simple. We can no longer say that the snake as a whole occupies the same region as a proper part of it does, as the snake no longer has any proper parts. But there seems to be a difference between the aethereal snake being wound twice around the loop and its being wound only once around it.

If we accept the possibility of aethereal objects that can self-overlap and extended simples, we need a way to describe the above situation. A nice way uses the concept of internal space and internal geometry. The snake's internal geometry does not change significantly as the spiral tightens. But the relationship between the internal space and the external space changes a lot, so that two different internal coordinates come to correspond to a each external coordinate. That's basically how my animation code works: there is an internal coordinate that ranges from 0 to 720 as one moves along the snake's centerline (backbone?), which is then converted to external xyz-coordinates. Initially, the map from the internal coordinate to the external one is one-to-one, but once things are completed, it becomes two-to-one (neglecting end effects).

The idea of internal and external space allows for many complex forms of self-intersection of extended simples. And all this is great for Aristotelians who are suspicious of parts of substances.

Fission and making the world have been a happier place

One theory about what happens in cases of personal fission is this. If a person is split, then there were two colocated people there all along. This fits best with four-dimensionalism. There are, in cases of fission, two people who overlap for a part of their four-dimensional career.

Here is a curious consequence. Suppose that Jim has led a very happy life. Then if I were to split him, I would bring it about that there have always been two happy colocated people there. But increasing the number of happy people makes the world a happier place. So, were I to split Jim, I would make the world have been a happier place. Surely, though, we don't have the power to make the world have been a happier place. So we should reject this four-dimensionalist solution to the problem of fission.

Transgender realism, abortion, animalism and colocationism

There are two major families of views on our relationship to the biological world. On animalism, we are animals of the species homo sapiens. Animalism comes in two varieties: physicalist animalism says that we are purely physical animals and dualist animalism says that some or all animals, including all of us, have non-physical features such as non-physical mental states or a soul (of a Cartesian or an Aristotelian sort). On colocationism, wherever one of us is present, there is an animal of the species homo sapiens present as well, but we are not identical to such an animal. There are multiple varieties of colocationism. On the constitution view, we are wholly constituted by our associated animals. Typically, such constitution theorists are physicalists—the animals are purely physical and hence so are we. The other main variety of colocationism is further-aspect dualist colocationism on which our associated animals are purely physical, but we are not. This includes a view on which we are souls (which count as located wherever the ensouled bodies are), a view on which we are a composite of an animal and a soul and a view on which we are partly constituted by an animal and partly constituted by a non-physical aspect. The debate on animalism versus colocationism is thus to a significant degree orthogonal to the debate between physicalists and dualists.

If animalism is true, then a normal adult, say Sally, used to be a fetus, and to have killed that fetus would have been to kill Sally, and it would have deprived Sally of even more than killing Sally now would. Thus, animalism strongly suggests that abortion is wrong, though violinist-type arguments could be used to try to resist that conclusion. On the other hand, colocationist views are much more congenial to pro-choice philosophers, and hence appear to be somewhat dominant in the pro-choice moral philosophy scene. For if colocationism is true, then it could be that the human animal existed significantly before Sally came to be colocated with it, and if so, then killing that human animal in abortion would not have been a killing of Sally. Though, a colocationist could also think that colocation started at fertilization and hence a killing of the fetus would also be a killing of the colocated Sally.

So whether animalism or colocationism is the right metaphysics of us is very relevant to the moral status of abortion.

Now I will cautiously wade into waters that are rather unfamiliar to me, and I apologize if I use terminology in non-standard ways. The question of animalism versus colocationism appears to be very relevant to the question of transgender realism. Let Type I Transgender Realism (1TR) be the view that some people literally are men in female bodies or women in male bodies. Let Type II Transgender Realism (2TR) be the claim that some people who had female bodies and felt that they were or should be men are now, after gender reassignment surgery and hormonal treatment, literally men, and some people who had male bodies and felt that they were or should be women are now, after gender reassignment surgery and hormonal treatment, literally women. If 1TR is true, so is 2TR: surely a man in a female body does not cease to be a man after the body is surgically modified to be more male-like. But at the same time, the law in a number of jurisdictions tracks 2TR but not 1TR, requiring surgery for legal classification as male or female.

Now, it seems very plausible that whether a human animal is male or female (or hermaphrodite) depends on biological criteria very much like those by which we ask whether an elephant or a gecko or maybe even a plant is male or female (or hermaphrodite). These criteria do not depend on psychological states but on whether the organism is such that it should produce its own sperm or such that should produce its own eggs (or both). It is also very plausible that men are male (though they may be more or less feminine) and women are female (though they may be more or less masculine). So if we are human animals, then whether we are male or female, and hence whether we are men or women, depends solely on biological criteria, and 1TR is false.

Moreover, if we are human animals, then 2TR is also false, at least given the current surgical methods. If we remove a mouse's female reproductive system and reshape what remains to look like male genitalia, and treat with hormones, what we have is a female mouse that has lost its reproductive system and behaves like a male. It might be more complicated if a functioning male reproductive system is transplanted. But I think it would still be true that the resulting mouse isn't such that it should produce sperm. Moreover, the mouse doesn't produce its own sperm—it produces the donor's sperm. Here's another route to the conclusion that even a functioning male reproductive transplant doesn't turn the female mouse male. After mere removal of a female (respectively, male) mouse's reproductive system, what we have is a female (respectively, male) mouse that is missing a reproductive system. But now imagine two identical twin female mice, A and B. Both have their female reproductive systems removed. But B then has a male reproductive system added, and then removed. If B became male upon addition of the male reproductive system, then B should still be male after removal thereof—a male does not cease to be a male after losing the reproductive system, but becomes a mutilated male. But A and B may be exactly alike at the end of suffering all this cruelty. It would then be odd to say that of two exactly similar mice, one is male and one is female. So we should say that they are both female, and hence B was female all along, even while having the male reproductive system.

Maybe an animalist could get out of this argument by distinguishing between sex and gender, and denying the idea that a man is an adult male human and a woman is an adult female human. Instead, perhaps, a man is an adult masculine human and a woman is an adult feminine human. The appeal to non-human animals in my argument then becomes irrelevant because only human animals can be men and women. On this story, there will be a disnalogy between the triple of terms "human", "woman" and "man" and triples like "chicken", "hen" and "rooster". A hen is a female chicken, but a woman need not be a female human. While this animalist-compatible view would let one preserve 1TR and 2TR, it would not be compatible with the aspiration that "a woman in a man's body" may have to be really female. It is my impression it is more the genderqueer than the transgendered who use phrases like "male woman" or "female man". Besides the idea of literally male women and female men seems problematic.

On the other hand, if colocationism is true, it is much easier to hold to 1TR and 2TR. Sure, Sally's associated animal (the animal that she is partly or wholly constituted by) may be male, but perhaps maleness and femaleness in a human person is not simply determined by whether the human animal is male or female. Colocationism could allow one to hold to 1TR without revisionary biology and without the oddness of saying that Sally is a male woman. Moreover, colocationism makes it plausible that sexual reassignment surgery could be a valuable thing: it is fitting that a man be associated with a male animal and a woman with a female animal, and while my arguments above suggest that surgery will not change the sex of the associated animal, it could somewhat improve the fit between the person and the associated animal.

Of course, colocationism by itself does not imply 1TR or 2TR: one could still think that a person is a man if and only if the person is associated with an adult male human animal and that a person is a woman if and only if the person is associated with an adult female human animal. But colocationism opens options beyond that.

So the debate between animalism and colocationism is not only highly relevant to the abortion debate but also to the question of transgender realism. Settling the question between the animalists and colocationists would not completely settle the latter two questions, but it would lead to significant progress.

Let me end by saying, without argument, that we are primates and all primates are animals. Hence animalism is true.

Colocationism and the Incarnation

According to abundant forms of colocationism, where I sit, there sit an infinity of other individuals. One of these individuals is a human-shaped mound of flesh and blood. Another is a philosopher. Yet another is something one might call a "rigid human figure" (which I will explain below). These individuals are all related to me in having the same matter. Their distinctness can be seen from the fact that they have different persistence conditions. Thus, the mound of flesh and blood can survive my death, while the philosopher came into existence significantly after I did. The rigid human figure does not survive changes in the orientation of bodily parts. According to sparser forms of colocationism, we may have a more limited number of individuals present here—only the objects that fulfill some philosophically explanatory role will be posited. Thus, the sparse colocationist will probably admit the human-shaped mound of flesh and blood, but probably will not admit the philosopher or the rigid human figure.

Colocationism, whether abundant or sparse, multiplies individuals where there is a multiplicity of what one might with significant propriety call "natures". This creates a prima facie problem for the Incarnation. For if such things as being a human and being a mound of flesh and blood count as individual-defining natures, surely so will being a human and being divine. But then the colocationism seems to imply that where Jesus is, there are two distinct individuals, one of whom is human and the other of whom is divine. This is Nestorianism. (We are used to formulations of Nestorianism that use the word "person" instead of "individual". But we could also have used "individual" as our gloss on "hupostasis"—the Greek does not have the personal implications of the Latin. In any case, both of the individuals will be persons, so there will be two persons.)

This is a prima facie problem for colocationism (I assume, of course, that the orthodox doctrine of the Incarnation is true). Colocationism's multiplication of individuals seems to multiply Jesus into at least two individuals. One attempted solution to the problem might be to say that there is only one nature there, maybe "Godhumanhood". But that, of course, threatens monophysitism, unless one can argue that the sense of "nature" here is sufficiently different from that of the Council of Chalcedon. Maybe if one makes the right distinctions, one can get out of this problem. But it's going to be hard (every account of the Incarnation is hard, but here there seems to be an additional difficulty).

Abundant colocationism has a further problem. There will be an infinitude of individuals where Jesus is. A human, a teacher, a carpenter, the King of Israel, the Messiah, etc. Even if somehow we manage to collapse the human and the divine individuals into one—if not, we get Nestorianism—what do we say about all these other individuals? Are they, for instance, individuals worthy of our worship? Presumably not all—for only three individuals in existence are worthy of worship (in the sense of latria): the Father, the Son and the Holy Spirit. The carpenter, the teacher, the King of Israel, the Messiah and the mound of flesh and blood all share the matter of the (incarnate) Son, but are distinct from the Son, and a fortiori from the Father and the Holy Spirit. But there is something more than a little odd about saying that the Messiah is not to be worshiped. Moreover, while this particular multiplication of individuals may not violate the letter of the Council of Ephesus, it seems to be very much in the Nestorian spirit. If it was bad to have two individuals, having an infinitude surely is also problematic. We want to be able to say that the individual that Jesus' disciples were taught by was the Son of God. But when Jesus' disciples were taught by the teacher (whom else do we attribute teaching to in the primary sense but the teacher?), then it seems they were taught by someone other than the Son of God on the colocationist view.

The sparse colocationist has less trouble, perhaps. She might only have the flesh and blood and the human being to deal with. To avoid literal Nestorianism, she will say that the human being is the same individual as the Logos. The mound of flesh and blood will still be problematic, though, in light of the fact that we are told by Scripture that the Logos became flesh. We do not want to leave the flesh and blood too far outside the bounds of the Incarnation.