John Locke says that his version of a personal identity criterion is necessary for just reward and punishment. Is a criterion really necessary? If so, is Locke's the criterion we should use?

        Reward works similarly.  Locke says, “happiness and misery being that for which every one is concerned for himself, and not mattering what becomes of any substance not joined to, or affected with that consciousness.” (Page 46) Just as we want to punish the very same person who robs a bank or kicks an old lady, we also want to make sure the Purple Heart medal goes to the very same person who was injured in battle.  Does Locke’s criterion help us accomplish this? It seems like it doesn’t.  In the actual practice of administering justice, memory links rarely enter the picture.

        On Locke’s view, though, if a person performs an action, commendable or criminal, and later is unable to remember it, then he is not responsible for the action.  If a person can’t remember doing something, then it was not he who did it.  This claim naturally perks the interest of the man in jail for crimes committed while so intoxicated that he presently can’t remember doing what landed him behind bars.  Locke predicts an objection, “But is not a man drunk and sober the same person?” (Page 48)  Locke’s expert testimony won’t help the jailbird in trial, though, because Locke explicitly says we should punish a sober man for his drunken actions, “Human laws punish both, with a justice suitable to their way of knowledge.” (Page 48) Locke supports justice systems set up by humans because there’s no practical way to administer memory tests to find out who remembers committing a crime and who doesn’t, “because the fact is proved against him, but want of consciousness cannot be proved for him.” (Page 48)  Imperfect though the results may be, it’s the most pragmatic thing to do with the available resources.

        Locke saves himself from contradiction, though, by appealing to the difference between the practical matter of society enforcing laws and the divine justice that can come from an omniscient deity: “But in the great day, wherein the secrets of all hearts shall be laid open, it may be reasonable to think, no one shall be made to answer for what he knows nothing of; but shall receive his doom, his conscience accusing or excusing him.” (Page 48) So Locke condones human laws that punish someone for doing something they can’t recall, but he believes in the end some sort of divine power will justly excuse them.  Locke alludes to a Judgment Day when (presumably) God will evaluate a person’s life and no one will be damned for anything he can’t remember anymore.

        But if Locke’s criterion is only to be used in divine justice, then why is it necessary?  He doesn’t think it needs to be included in human systems of law.  Presumably, any God who’s doling out ultimate reward and punishment wouldn’t need instructions from Locke.  The omniscient God Locke brings up would know how to administer reward and punishment without a litmus test for personal identity.

        It’s strange that Locke is willing to pardon the drunken actions of a man who can’t remember them later for two reasons: First, because the sober person after the drunken incidents seems to be the same person as the sober person as before the drunken incidents, and second, because the drunken person and the earlier sober person both seem to be able to reasonably anticipate being the same person as the later person.  Reid’s brave officer objection makes a similar point about memory links: If a General remembers being a young man in battle from some years ago, and when he was at that battle he remembered being flogged as a boy, but the General now has no memory of being flogged, are the boy and the General the same person?  It seems as if the boy and the young man are the same person and the young man and the General are the same person, then the answer is yes.  Locke denies this, saying there is no law of transitivity for personal identity.

         But does chronology make a difference?  It can seem reasonably possible to say that things that happened in youth that you can’t remember aren’t really attributable to you.  It’s much more absurd to say that dancing on the bar at 10:30 last night wasn’t you, but that doing the keg stand one hour earlier and throwing up the next morning was.  What happened in between?  Surely identity can’t pop in and out of existence.  If it did, what ramifications would it have on reward and punishment?  Should someone only be imprisoned until they can’t remember their crime anymore?

        If there exists a person whose memory links could be represented by the diagram below, then a few premises seem immediately clear on Locke’s account:

1. A=B, because B can remember the experiences of A.
2. A=C, because C can remember the experiences of A

Locke would want to say that C is not the same person as B, because C doesn’t have any memories of B’s experiences, and to him C equals B if and only if C does have memories of B’s experiences.  This contradicts the law of transitivity of identity, though, the logical principle that if A = B, and B = C, then A = C.  Locke denies that the logical law applies to personal identity, but it still seems intuitively like it should apply. Locke’s view would only hold if the intoxication (or insanity) of B was so severe that B at time t2 couldn’t have memories of A at time t1. To escape this objection, Locke can reformulate his view in three ways.  Otherwise, his criterion seems off, and so unfit for determining any kind of justice.

        The first thing he could say is that A is equal to B if and only if either A and B satisfy his memory criterion or A=C and B=C for some C.  The second way he could restructure his claim is to say that A=B if and only if either A and B satisfy his memory criterion or if B and A satisfy an anticipation criterion.  An anticipation criterion would allow B to count as the same person as A if B could reasonably anticipate experiencing the future actions of A.  The third way he could amend his statements is to say that rather than direct memory connection establishing identity, it could also be done through a series of memory links.  This would mean, for example, that the General would count as the flogged boy because the General remembers being the young man and the young man remembers being the boy.