sam brown, explodingdog
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 refurbished ship the same ship as the original. Or we can decide to call the ship reconstructed out of the discarded pieces the same ship as the original. It’s up to us.
This kind of view may be called Conventionalism about identity, because it says that the facts in question are ones we choose, by adopting one convention (pattern) for how to count and talk about ships, rather than another. (Similar to how facts abiut what’s fashionable are up to us by our choosing to buy, wear, and approve such-and-such styles rather than others.)
As a view about things like ships and churches, this view has some appealing features. It also has some shortcomings. We won’t try to settle how satisfying we should find it as a proposal about those kinds of things. What we’ll consider instead is how to think about a parallel treatment of questions about the numerical identity of persons (you and me).
Let’s look at a few problem cases. We’ll see that the Conventionalist response to these problem cases is intuitively pretty unsatisfactory.
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 injuries. 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.
Further investigation reveals: the mad 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 nefarious 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 those terrible 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 crimes 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 mayhem and 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 liable for the damages your body caused on Monday? Should you be punishable?
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 somewhat 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 pre-existing fact of the matter about whether the person in the police holding cell is who’s responsible for the crimes, whether they are the same person who 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. They think there is a fact of the matter. They think they really are innocent. It was somebody else who committed those crimes. Regardless of what people decide to say about their case.
Here’s a third case. Forget about the crimes described above. 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 will it be the niece’s life?)
You don’t mind the prospect of losing your memories and personality so much, in themselves. But you do worry 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 and Conceptual Decisions met last week to discuss cases like yours. They decided that we will all call the person with 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. You’re worried about whether you will ever wake up after the procedure. This concern doesn’t seem to be addressed by decisions or conventions about how people will use the words “the same person.”
This is why Conventionalism seems an unsatisfactory picture of what being the same person consists in.