Phil 89: Conventionalism about Identity

One view about the Ship of Theseus is that there is no answer yet to the question which ship is identical to the original ship. There is no answer yet because our concept of a ship hasn’t been designed to give answers to problem cases of that sort. But we can just decide to extend our concept of a ship, in either direction. We can decide to call the carefully repaired ship the same ship as the original. Or we can decide to call the ship built out of the discarded pieces the same ship as the original. It’s up to us.

We will not address the merits or demerits of this view as a view about ships. However, we will be concerned with whether this is a satisfactory line to take on questions about personal identity.

Let’s look at a few problem cases. We’ll see that the conventionalist response to these problem cases is intuitively pretty unsatisfactory.

Amnesia and Memory Implants

Can you survive total and irreversible amnesia? There is some temptation to say that we’d still have the same person, after the amnesia. After all, we’d still have the same body. But there is also some temptation to say that, because the person’s personality and memories have been “wiped clean,” now we’re dealing with a new person, who is numerically different from the person who existed before the amnesia.

Consider the following story. You wake up on Tuesday morning and find yourself in jail. You learn you were arrested for blowing up Davis Library on Monday, causing millions of dollars of damage and several deaths. But you have no memory at all of what happened on Monday. The last thing you remember is going to bed Sunday night. Yet there are videotapes which clearly show you setting the bomb off on Monday, and you were arrested at the scene of the crime.

sam brown, explodingdog

Further investigation reveals: the evil scientist Dr Evil has discovered a way to temporarily implant his personality and plans into other people’s brains. He kidnapped you on Sunday night and did this to you. On Monday, your body awoke with Dr Evil’s personality. Knowing that the effect would last only 24 hours, this person — whoever it was — spent all day carrying out evil deeds, culminating in the destruction of Davis Library. After this person was arrested, he or she fell into a coma, and awoke on Tuesday with all of your old personality traits and complete amnesia about what happened on Monday.

Now you’re on trial. There is no dispute that it was your body that did all the evil deeds on Monday. So that person — the one who committed the acts on Monday — deserves to be punished. But you think you should go free, because that person was somebody else. It wasn’t you.

Could you appeal to temporary insanity as a defense? This is not clear. The person who committed the evil deeds on Monday knew very clearly what he or she was doing. In fact this person delighted in the fact that he or she was causing so much suffering. If Dr Evil had merely molded you into a disciple, and then you went and committed those deeds in the same way, that wouldn’t have excused you or let you avoid punishment. (Of course, Dr Evil should also be punished — if only the authorities could catch him! But his deserving some blame doesn’t make you innocent.)

What do you think? Should you be punished for the acts on Monday?

Here’s a second case. Suppose the jury lets you go free. Then you think, hey maybe this is a good way to get rid of my mean professor. You attempt to build a device that works just like Dr Evil’s device, but your device ends up working a bit differently. Its effects are always permanent. So what you do is this. You “store” some innocent person’s personality into the device. Then you go and finish off your professor. Then you sit down, right at the scene of the crime, and run the device on yourself. Now all your memories are permanently erased, you get a new personality, and so on. This is the way you plan to escape punishment.

What do you think? Should the person who’s discovered at the scene of the crime be allowed to go free?

How would the conventionalist respond to these questions? He’d say, in each case, we just have to get together and decide whether we’re going to call the person who committed the crimes “the same person” as the person the police have in their custody. That’s all there is to it. There is no fact of the matter about whether the person in the police holding cell is responsible for the crimes, or whether this person ought to be punished. Whatever we decide to say will be alright.

This won’t sound very fair to the person in the police holding cell. He thinks there is a fact of the matter. He thinks he really is innocent. It was somebody else who committed those crimes. Regardless of what people decide to say about his case.

Here’s a third case. Forget about the crimes we just described. Suppose you’re out hiking in the Smokies, and you come across Dr Evil’s secret hideout. His henchmen capture you and put you in a cell. Dr Evil tells you that he needs to test out a new memory implant device, so that tomorrow morning he’s going to “erase” all your current memories and personality, and implant new ones. (Perhaps the memories and personality of Dr Evil’s young niece.) Then he’ll set you free, to go about your life (or the niece’s life)?

You don’t mind the prospect of losing your memories and personality so much, in themselves. But you worry about whether the person with the new memories and personality will be you. You fear that it won’t be you, but rather a new person in your body. You fear that undergoing this procedure will be the end for you.

It doesn’t seem like it would be much comfort if your jailer told you, “Don’t worry. The Committee on Linguistic Reform met to discuss such cases last week. They decided that we will all call the person with the new memories and personality ‘the same person’ as you.”

As you’re sitting in your cell in Dr Evil’s hideout, you have a concern for your own continued existence. This concern doesn’t seem to be addressed by linguistic decisions about how people will use the words “the same person.” This is why conventionalism seems an unsatisfactory answer about what the identity of persons consists in.