What makes personal identity

As will become clear below, this reading dates back at least as far as Thomas Reid. Of course, it is the case that the way a person extends their consciousness backward is via memory. Nevertheless, as Margaret Atherton points out, Locke talks at length about forgetfulness, and if consciousness just is memory, then we cannot make sense of consciousness at any given moment where a person is not invoking memory — The identity of consciousness is what allows for the persistence of any person, just as the identity of life is what allows for the persistence of any animal.

No one else can have my consciousness any more than any organism can have my life. Atherton Under this reading, what Locke means when he says that sameness of person consists in sameness of consciousness, is that any person extends back only to those mental events or acts which they take to be their own.

There might be a worry that under this kind of reading, Locke gives persons too much authority. I do not willfully disown one act and appropriate another; instead I accept what my consciousness reveals to me.

There is also a severe limit on that authority, imposed by the transitivity of identity,. From these treatments it is still difficult to discern what consciousness is for Locke, however. Weinberg Thus, Weinberg contends that the identity, or continued existence, of consciousness consists in a metaphysical fact, rather than appropriation. Nevertheless, Weinberg additionally argues that the first personal conscious experience of our own mental states, whether those states are occurrent sensations, reflections, or via remembering is a necessary, but not sufficient, condition of personal identity.

In other words, to have the awareness or knowledge of an ongoing self—or 2 —we must have 1. There are those who take Locke to be truly agnostic. But, there are others who think that Locke overstates the probability that souls are immaterial substances, so as not to ruffle the feathers of Stillingfleet and other religious authorities. Some in the latter group think that Locke leans toward materialism.

This raises questions about how far Anthony Collins discussed below departs from the Lockean picture, or the degree to which Locke anticipates later materialist pictures of persons. Many such philosophers argue that numerical identity consists in no change at all , and the only kind of entity that allows for identity in this strict sense is an immaterial substance.

As Joseph Butler puts it,. This wonderful mistake may possibly have arisen from hence; that to be endued with consciousness is inseparable from the idea of a person, or intelligent being. For this might be expressed inaccurately thus, that consciousness makes personality: and from hence it might be concluded to make personal identity. One of the points that Locke emphasizes—that persistence conditions are determined via defining kind terms—is what, according to Butler, leads Locke astray.

Butler additionally makes the point that memory is not required for personal persistence. He says,. But though present consciousness of what we at present do and feel is necessary to our being the persons we now are; yet present consciousness of past actions or feelings is not necessary to our being the same persons who performed those actions, or had those feelings. The most popular, or well known, version of this line of objection comes from Thomas Reid He says:.

Suppose a brave officer to have been flogged when a boy at school for robbing an orchard, to have taken a standard from the enemy in his first campaign, and to have been made a general in advanced life; suppose, also, which must be admitted to be possible, that, when he took the standard, he was conscious of his having been flogged at school, and that, when made a general, he was conscious of his taking the standard, but had absolutely lost the consciousness of his flogging.

These things being supposed, it follows, from Mr. Whence it follows, if there be any truth in logic, that the general is the same person with him who was flogged at school. Therefore, the general is, and at the same time is not, the same person with him who was flogged at school. Reid [ —]. When we do, Reid expects we will conclude that the general C is the same person as he who took the standard from the enemy B because the general C remembers doing so.

Additionally he who took the standard from the enemy B is the same person as he who was flogged at school for robbing the orchard A because he B remembers that past traumatic experience. Thus C he who is was made general is identical to B he who took the standard and B he who took the standard is identical to A he who was flogged at school.

Given the law of transitivity which says that if C is identical to B and B is identical to A, then C is identical to A , we should conclude that C the general is identical to A the flogged school boy. This is because C the general has no consciousness or memory of having been flogged at school A.

This and other similar objections are meant to show that if we place the identity of persons in the identity of consciousness, as Locke suggests, then we run into a problem—namely one of contradiction—for we get the result that C and A both are, and are not, identical.

Importantly, these are objections to which sympathetic readers of Locke are still responding see Atherton , Weinberg , LoLordo , Thiel , Garrett , Schechtman , etc. One such philosopher is Catharine Trotter Cockburn. Cockburn pens her Defence of Mr. Specifically, these pamphlets charge Locke with not proving that the soul is immortal, or threatening proofs of the immortality of the soul.

Cockburn is quick to defend Locke, but proceeds carefully and thoroughly as she does so. Cockburn points out that Locke never sets out to prove the soul immortal, and Locke actually claims that it is more probable that the soul is immaterial, than material. Moreover, even if Locke is not committed to the soul being immaterial, this ought not threaten proofs of the immortality of the soul.

This is because what allows Locke to speculate that God could have superadded thinking to formerly inert systems of matter is that God is omnipotent, and surely an omnipotent being could make souls immortal even if they are material.

Of this she says,. If then this proposition, that the soul always thinks , does not prove, that it is immortal, the contrary supposition takes not away any proof of it; for it is no less easy to conceive, that a being, which has the power of thinking with some intervals of cessation from thought, that has existed here for some time in a capacity of happiness or misery, may be continued in, or restored to the same state, in a future life, than that a Being which always thinks, may be continued in the same state.

Cockburn, in Sheridan ed Additionally, there is ample evidence that Locke thinks the soul is immortal, and that persons will go on to receive divine punishment and reward in the next life for their deeds in this life. This comes through not just in L-N 2. Just as a body that was in motion and comes to rest does not become a new body once it starts moving again, a soul that was thinking and ceases to think does not become a new soul once thought is restored to it.

To this it might also be added that even if we awake with new souls each morning, it need not mean that we are new persons each morning, according to Locke. Moreover, the persistence of any person does not always align with the persistence of a human being or soul, as many assume.

Making this point is the purpose of those imaginary cases. Law moves from this point to the conclusion that Locke thinks persons are modes or attributes rather than substances or things in themselves. Now the word Person , as is well observed by Mr. Locke …is properly a forensick term, and here to be used in the strickt forensick sense, denoting some such quality or modification in man as denominates him a moral agent, or an accountable creature; renders him the proper subject of Laws , and a true object of Rewards or Punishments.

This is significant since whether Lockean persons are best thought of as substances, modes, or relations is something that is still debated amongst Locke scholars today. It still leaves important questions unanswered, however. Suppose we could somehow copy all the mental contents of your brain to mine, much as we can copy the contents of one computer drive to another, and that this erased the previous contents of both brains. Whether this would be a case of psychological continuity depends on what sort of causal dependence counts.

The resulting being with my brain and your mental contents would be mentally as you were before, and not as I was. He would have inherited your mental properties in a way—but a funny one. Is it the right way? Psychological-continuity theorists disagree Shoemaker —, says yes; Unger 67—71 says no; see also van Inwagen Schechtman gives a different sort of objection to the psychological-continuity strategy.

A more serious worry for psychological-continuity views is that you could be psychologically continuous with two past or future people at once. Any psychological-continuity view will imply that she would be you. If we destroyed one of your cerebral hemispheres, the resulting being would also be psychologically continuous with you. Hemispherectomy—even the removal of the left hemisphere, which controls speech—is considered a drastic but acceptable treatment for otherwise-inoperable brain tumors: see Rigterink What if we did both at once, destroying one hemisphere and transplanting the other?

Then too, the one who got the transplanted hemisphere would be psychologically continuous with you, and would be you according to the psychological-continuity view. But now suppose that both hemispheres are transplanted, each into a different empty head. The two recipients—call them Lefty and Righty—will each be psychologically continuous with you.

The psychological-continuity view as we have stated it implies that any future being who is psychologically continuous with you must be you. It follows that you are Lefty and also that you are Righty. But that cannot be: if you and Lefty are one and you and Righty are one, Lefty and Righty cannot be two. And yet they are: there are indisputably two people after the operation.

One thing cannot be numerically identical with two things that are distinct from each other. If you are Lefty, you are hungry at that time. If you are Lefty and Righty, you are both hungry and not hungry at once: a straight contradiction. Psychological-continuity theorists have proposed two different solutions to this problem. What we think of as you is really two people, who are now exactly similar and located in the same place, doing the same things and thinking the same thoughts.

The surgeons merely separate them Lewis , Noonan —42; Perry offers a more complex variant. For each person, there is such a thing as her first half: an entity just like the person only briefer, like the first half of a meeting. They are like two roads that coincide for a stretch and then fork, sharing some of their spatial parts but not others. At the places where the roads overlap, they are just like one road. Likewise, the idea goes, at the times before the operation when Lefty and Righty share their temporal parts, they are just like one person.

Whether we really are composed of temporal parts, however, is disputed. Its consequences are explored further in section 8. The other solution to the fission problem abandons the intuitive claim that psychological continuity by itself suffices for us to persist. It says, rather, that a past or future being is you only if she is then psychologically continuous with you and no other being is.

There is no circularity in this. We need not know the answer to the persistence question in order to know how many people there are at any one time; that comes under the population question. This means that neither Lefty nor Righty is you.

They both come into existence when your cerebrum is divided. If both your cerebral hemispheres are transplanted, you cease to exist—though you would survive if only one were transplanted and the other destroyed. Fission is death. Shoemaker 85, Parfit ; 6f. That looks like the opposite of what we should expect: if your survival depends on the functioning of your brain because that is what underlies psychological continuity , then the more of that organ we preserve, the greater ought to be your chance of surviving.

In fact the non-branching view implies that you would perish if one of your hemispheres were transplanted and the other left in place: you can survive hemispherectomy only if the hemisphere to be removed is first destroyed. This seems mysterious. Why should an event that would normally preserve your existence bring it to an end if accompanied by a second such event—one having no causal effect on the first?

If your brain is to be divided, why do we need to destroy half of it in order to save you? For discussion, see Noonan 12—15 and ch. The problem is especially acute if brain-state transfer counts as psychological continuity. In that case, even copying your total brain state to another brain without doing you any physical or psychological harm would kill you. The non-branching view makes the What matters? Faced with the prospect of having one of your hemispheres transplanted, there is no evident reason to prefer having the other destroyed.

Most of us would rather have both preserved, even if they go into different heads. Yet on the non-branching view that is to prefer death over continued existence.

This leads Parfit and others to say that that is precisely what we ought to prefer. We have no reason to want to continue existing, at least for its own sake. What you have reason to want is that there be someone in the future who is psychologically continuous with you, whether or not she actually is you. The usual way to achieve this is to continue existing yourself, but the fission story shows that this is not necessary.

Likewise, even the most selfish person has a reason to care about the welfare of the beings who would result from her undergoing fission, even if, as the non-branching view implies, neither would be her. In the fission case, the sorts of practical concerns you ordinarily have for yourself apply to someone other than you.

This suggests more generally that facts about who is who have no practical importance. All that matters practically is who is psychologically continuous with whom. Lewis and Parfit debate whether the multiple-occupancy view can preserve the conviction that identity is what matters practically. Another objection to psychological-continuity views is that they rule out our being biological organisms Carter , Ayers —, Snowdon , Olson 80f. This is because no sort of psychological continuity appears to be either necessary or sufficient for a human organism to persist.

Human organisms have brute-physical persistence conditions. If your brain were transplanted, the one who ended up with that organ would be uniquely psychologically continuous with you and this continuity would be continuously physically realized. On any psychological-continuity view, she would be you: the person would go with her transplanted brain. But no organism would go with its transplanted brain.

The operation would simply move an organ from one organism to another. So it seems, anyway. It follows that if you were an organism, you would stay behind with an empty head. Even though this is never going to happen, it shows that according to psychological-continuity views we have a property that no organism has, namely possibly moving from one organism to another by brain transplant. Again, a human organism could continue existing in an irreversible vegetative state with no psychological continuity.

If you were an organism, you could too. But according to psychological-continuity views you could not. It follows that human animals have a property that we lack, namely possibly surviving as a vegetable.

But a healthy, adult human organism seems a paradigm case of a thinking being. If human organisms can think, yet as psychological-continuity views imply we are not organisms, three difficulties arise. First, you are one of two intelligent beings sitting there and reading this entry. More generally, there are two thinking beings wherever we thought there was just one. Second, the organism would not merely think in some way or other, but would presumably be psychologically indistinguishable from you.

In that case it cannot be true that all people or even all human people persist by virtue of psychological continuity. Some—those that are organisms—would have brute-physical persistence conditions. Third, it becomes hard to see how you could know whether you were a nonanimal person with psychological persistence conditions or an animal person with brute-physical ones.

If you thought you were the nonanimal, the organism would use the same reasoning to conclude that it was too. For all you could ever know, it seems, you might be the one making this mistake. We can make this epistemic problem more vivid by imagining a three-dimensional duplicating machine.

The process causes temporary unconsciousness but is otherwise harmless. Two beings wake up, one in each box. The boxes are indistinguishable. Because each being will have the same apparent memories and perceive identical surroundings, each will think, for the same reasons, that he or she is you.

But only one will be right. Suppose the technicians who work the machine are sworn to secrecy and immune to bribes. Did I do the things I seem to remember doing? Am I a nonanimal that would go with its transplanted brain, or an animal that would stay behind with an empty head?

The most popular defense of the psychological-continuity view against this objection is to say that, despite sharing our brains and showing all the outward signs of consciousness and intelligence, human organisms do not think and are not conscious. Thinking animals are not a problem for psychological-continuity views for the simple reason that there are none Shoemaker 92—97, Lowe 1, Johnston 55; Baker is a subtle variant.

If human organisms cannot be conscious, it would seem to follow that no biological organism of any sort could have any mental properties at all. Shoemaker argues that this follows from the functionalist theory of mind , , Another option is to concede that human organisms are psychologically indistinguishable from us, but try to explain how we can still know that we are not those organisms.

The best-known proposal of this sort focuses on personhood and first-person reference. It says that not just any being with mental properties of the sort that you and I have—rationality and self-consciousness, for instance—counts as a person. A person must also persist by virtue of psychological continuity.

It follows that human animals are not people thus solving the second problem, about personhood. So the organism is not mistaken about which thing it is: it has no first-person beliefs about itself at all. And you are not mistaken either. You can know that you are not the animal thinking your thoughts because it is not a person and personal pronouns never refer to nonpeople thus solving the third, epistemic problem.

See Noonan , , Olson ; for a different approach based on epistemic principles see Brueckner and Buford Or one could say that human organisms have psychological persistence conditions. Despite appearances, the transplant operation would not move your brain from one organism to another, but would cut an organism down to the size of a brain, move it across the room, and then give it new parts to replace the ones it lost—presumably destroying the animal into which the brain is implanted.

This may be the view of Wiggins , and McDowell , and is unequivocally endorsed by Madden ; see also Langford , Olson — None of these objections arise on animalism, the view that we are organisms. This does not imply that all organisms, or even all human organisms, are people: as we saw earlier, human embryos and animals in a persistent vegetative state may not count as people.

Being a person may be only a temporary property of you, like being a student. Nor does animalism imply that all people are organisms. It is consistent with the existence of wholly inorganic people: gods or angels or conscious robots. It does not say that being an animal is part of what it is to be a person a view defended in Wiggins and Wollheim ch.

Animalism leaves the answer to the personhood question entirely open. Assuming that organisms persist by virtue of some sort of brute-physical continuity, animalism implies a version of the brute-physical view.

Some endorse a brute-physical view without saying that we are animals. They say that we are our bodies Thomson , or that our identity through time consists in the identity of our bodies Ayer This has been called the bodily criterion of personal identity. It is obscure, and its relation to animalism is uncertain. Olson, Eric T. Edited by Edward N. Usefully distinguishes seven separate problems of personal identity, then focuses on identity over time, with particular attention to different versions of the question.

Penelhum, T. Edited by Paul Edwards, 95— New York: Macmillan, A sophisticated discussion of Locke, Hume, and the debates of their day about evidential criteria of personal identity over time. Perry, John. Edited by John Perry, 3— Berkeley: University of California Press, A lively and accessible introduction to traditional debates on personal identity over time.

Originally published in Users without a subscription are not able to see the full content on this page. But if my sister does exist, then what is she, and what makes that thing that she now is identical with the beautiful girl laughing at her little sister on that forgotten day? Alan Watts had an answer , but Goldstein is more interested in the question itself as a gateway to our deepest humanity:.

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