Wednesday, January 11, 2006

Brain in A Vat Drives Runaway Trolley

Consider the following case: A brain in a vat is at the wheel of a runaway trolley approaching a fork in the track. The brain is hooked up to the trolley in such a way that the brain can determine which course the trolley will take. There are only two options: the right side of the fork or the left side. There is no way to derail or stop the trolley and the brain is aware of this.

On the right side of the track there is a single railroad worker, Jones, who will definitely be killed if the brain steers the trolley to the right. If Jones lives he will go on to kill five men for the sake of thirty orphans (one of the five men he will kill is planning to destroy a bridge that the orphans' bus will be crossing later that night). One of the orphans who will be killed would have grown up to become a tyrant who made good, utilitarian men do bad things, another would have become John Sununu, and a third would have invented the pop-top can.

If the brain in the vat chooses the left side of the track, the trolley will definitely hit and kill another railman, Leftie, and will hit and destroy ten beating hearts on the track that would have been transplanted into ten patients at the local hospital who will die without donor hearts. These are the only hearts available, and the brain is aware of this. If the railman on the left side of the track lives, he, too, will kill five men--in fact, the same five that the railman on the right would kill.

However, Leftie will kill the five as an unintended consequence of saving ten men: he will inadvertently kill the five men as he rushes the ten hearts to the local hospital for transplantation. A further result of Leftie's act is that the busload of orphans will be spared. Among the five men killed by Leftie is the man responsible for putting the brain at the controls of the trolley. If the ten hearts and Leftie are killed by the trolley, the ten prospective heart-transplant patients will die and their kidneys will be used to save the lives of twenty kidney-transplant patients, one of whom will grow up to cure cancer and one of whom will grow up to be Hitler. There are other kidneys and dialysis machines available, but the brain does not know this.

Assume that the brain's choice, whatever it turns out to be, will serve as an example to other brains in vats, and thus the effects of its decision will be amplified. Also assume that if the brain chooses the right side of the fork, an unjust war free of war crimes will ensue, whereas if the brain chooses the left fork, a just war fraught with war comes will result. Furthermore, there is an intermittently active Cartesian demon deceiving the brain in such a way that the brain is never sure if it is being deceived. Question: Ethically speaking, what should the brain do? Justify your answer.

Harper's Magazine, May 1996, pp 26-30.


Blogger wiploc said...

1. Single railroad worker: that's a wash, since we kill one either way.

2. Five men: Another wash. Again, they die either way.

3. Thirty orphans: Same as above. If the same five men die, the orphans will live either way (and the Hitler, Sunnunu, and pop tops issues cancel out too).

4. Ten hearts and twenty livers, and the brain doesn't know about the extra livers: Tough one. I'll have to think about it.

5. Unintended consequence: Is it better to have Rightie kill five men on purpose (for a good cause) or to have Leftie kill them accidentally (for a good cause with bad side effects)? Again, difficult. I don't see any clear path through this thicket, so I'll hope that there's some other, clearer, way to make the choice.

6. Intermittently active Cartesian demon: I'm not sure what this means. Maybe it just means that we can never be sure that we don't live in the Matrix. The hypothetical situation gives the brain knowledge of the future that it couldn't really have, and now the demon, to an unknown degree, takes it away. I think utilitarianism is the basis of all viable moral systems; and I think that, in our ignorance about the effects of our actions, we have to be rule utilitarians. But a god, because of his omniscience, would be an act utilitarian. Perhaps this Cartesian demon's effect is to give the brain enough doubt that it has to be a rule utilitarian. A rule utilitarian isn't going to squash the hearts in order to distribute the livers any more than she would take the hearts out of healthy people in order to make their livers available. So the brain should, at this point in the analysis, turn right to save the hearts.

7. Just war with crimes versus unjust war without crimes: I'm hard pressed to figure out what a just war would be. One side or the other has to be in the wrong, so every war has to have at least one unjust participant. So maybe this issue is about whether the brain's team will be the just one. Let's say the brain is American, and America will either instigate an unjust war and behave with propriety or a just war and behave badly. When I was a kid, I'd have been horrified by us starting a war on false pretenses. But by now I'm used to that. It's not that I like it, but I consider it par. But I'm still not used to stuff like Abu Graib. I don't like Americans torturing and lying. I'd like to nip that in the bud. So, as long as there's going to be a war anyway, and as long as we don't have a track record of just wars to defend, I'd like try to recover the white hat when it comes to war crimes. Let's not be total monsters: let's turn right!

Luckily, the answers to six and seven don't conflict; we turn right both times. My answer is that the brain should turn right.


9:40 AM  
Blogger Josh said...

My question is this: If "the brain in the vat" is an example of some sort of physicalism, does it really even have a choice since it is nothing more than matter in motion and is subsequently forced to follow whatever causality requires of it?

P.S. I'm glad that my Intro. to Phil. prof. never popped this one or I would have probably changed my major!

5:17 PM  
Blogger Jill Pole said...

Chris - my brain exploded somewhere around the car accident! (Not really, a student came in with a question and I don't have time to think about this right now.) Okay - now I'm back... Interesting quandry. I have a question, however. Please take this in the spirit that it is meant and not as an attack. I am genuinely interested in the answer. Why is important? Is there an application in this to a genuine moral decision? Why should I care about the brain in the jar? (Again, NOT an attack here. Just an English major wondering how philosophy works.)

3:36 PM  
Blogger chris said...

This story is a big joke. I'm surprised how many people took it seriously. Your intuition (that it seemed silly) is absolutely correct. I guess only philosophy majors "get it."

4:10 PM  
Blogger Josh said...

where did you get this from anyway? Or did you just pluck it from the ether? I'm tutoring Phil. 101 students this semester and I think this would be fun to use on them :)

5:31 PM  
Blogger Jill Pole said...

Now that I know you meant the joke, I feel free to laugh. I was a little afraid to make a sarcastic comment in case I stepped on some serious-thinkin' toes. :-) I think it's the "brain in a jar" bit that did it for me. I almost would have bought it if there had been a man driving the train. :-) :-)

10:44 PM  
Blogger wiploc said...

I just want it on record that I understood the question to be a joke. It's a parody of complex moral questions. I thought it would be funny to answer a question that was never intended to be answered. What surprised me was that it turned out to be answerable.


10:15 AM  
Blogger chris said...


Don't worry, I took your Herculean attempt at solving the puzzle to be a joke as well.

10:48 AM  

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