Wednesday, April 6, 2022

Consequentialism and probability

Classic utilitarianism holds that the right thing to do is what actually maximizes utility. But:

  1. If the best science says that drug A is better for the patient than drug B, then a doctor does the right thing by prescribing drug A, even if due to unknowable idiosyncracies of the patient, drug B is actually better for the patient.

  2. Unless generalized Molinism is true, in indeterministic situations there is often no fact of the matter of what would really have happened had you acted otherwise than you did.

  3. In typical cases what maximizes utility is saying what is true, but the right thing to do is to say what one actually thinks, even if that is not the truth.

These suggest that perhaps the right thing to do is the one that is more likely to maximize utility. But that’s mistaken, too. In the following case getting coffee from the machine is more likely to maximize utility.

  1. You know that one of the three coffee machines in the breakroom has been wired to a bomb by a terrorist, but don’t know which one, and you get your morning coffee fix by using one of the three machines at random.

Clearly that is the wrong thing to do, even though there is a 2/3 probability that this coffee machine is just fine and utility is maximized (we suppose) by your drinking coffee.

This, in turn, suggests that the right thing to do is what has the highest expected utility.

But this, too, has a counterexample:

  1. The inquisitor tortures heretics while confident that this maximizes their and others’ chance of getting into heaven.

Whatever we may wish to say about the inquisitor’s culpability, it is clear that he is not doing the right thing.

Perhaps, though, we can say that the inquisitor’s credences are irrational given his evidence, and the expected utilities in determining what is right and wrong need to be calculated according to the credences of the ideal agent who has the same evidence.

This also doesn’t work. First, it could be that a particular inquisitor’s evidence does yield the credences that they actually have—perhaps they have formed their relevant beliefs on the basis of the most reliable testimony they could find, and they were just really epistemically unlucky. Second, suppose that you know that all the coffee machines with serial numbers whose last digit is the same as the quadrilionth digit of π have been rigged to explode. You’ve looked at the coffee machine’s serial number’s last digit, but of course you have no idea what the quadrilionth digit of π is. In fact, the two digits are different. You did the wrong thing by using the coffee machine, even though the ideal agent’s expected utilities given your evidence would say that you did the right thing—for the ideal agent would know a priori what the quadrilionth digit of π is.

So it seems that there really isn’t a good thing for the consequentialist to say about this stuff.

The classic consequentialist might try to dig in their heels and distinguish the right from the praiseworthy, and the wrong from the blameworthy. Perhaps maximizing expected utility is praiseworthy, but is right if and only if it actually maximizes utility. This this still has problems with (2), and it still gets the inquisitor wrong, because it implies that the inquisitor is praiseworthy, which is also absurd.

The more I think about it, the more I think that if I were a consequentialist I might want to bite the bullet on the inquisitor cases and say that either the inquisitor is acting rightly or is praiseworthy. But as the non-consequentialist that I am, I think this is a horrible conclusion.

7 comments:

Walter Van den Acker said...

Alex

Why wouldn't the inquisitor's actions be right or praiseworthy if God is said to be right and praiseworthy for doing exactly thé same?

Tomasz M. said...

What about this: "the expected utilities in determining what is right and wrong need to be calculated according to the credences of the ideal agent who has the COMPLETE evidence"?

Walter Van den Acker said...

Tomasz

I wonder whether they inquisitor would be considered praiseworthy if it is actually true that their actions maximize their and other's chances of Hettinga into heaven.

Tomasz M. said...

Walter,

if it were the case that 1) the inquisitor's actions ACTUALLY maximized his and others' chances of getting into heaven, AND 2) the inquisitor tortured heretics while confident that this maximizes his and others’ chance of getting into heaven, AND 3) the inquisitor formed his credences on the basis of the most reliable testimony he could find, THEN I'm sure the inquisitor should be considered praiseworthy.
It would seem to me that all the 3 conditions should be satisfied for the action to be praiseworthy. Although maybe -- in some restricted sense -- it could be still argued that the inquisitor is praiseworthy only if his action meets 2) and 3). But in this case he would be not so much praiseworthy for the actual upshot but rather for following the rule to maximize the net expected utility.

Tomasz M. said...

This is of course what -- as I suppose -- a consequentialist could say ;)

Walter Van den Acker said...

Tomasz

I guess meeting the 3 conditions would come down to ... The credences of the ideal agent who has the complete evidence.

Tomasz M. said...

Walter,

Not necessarily. Consider this example given by Alexander Pruss:

You have unconscious miners trapped in one of two tunnels. You don't know which tunnel. They have air for six hours. It takes five hours to clear the way to one of the tunnels. There is only enough manpower to clear the way to one tunnel. You know that miners spend 75% of their time in tunnel A and 25% in tunnel B.

So to maximize the expected utility, we should dig to tunnel A. Consequently, I instruct the head of the rescue squad to dig to tunnel A. It turns out, however, that the head of the rescue squad misunderstood my words and -- believing that the miners spend 25% of their time in tunnel A and 75% in tunnel B -- ordered his squad to dig to tunnel B.

Fortunately, when the collapse happened, the miners were in tunnel B. In this case, I suppose a consequentialist would say that the head of the rescue squad is praiseworthy. I am also praiseworthy. Yet, neither I, nor head of the squad are ideal agents with complete evidence, even though we both meet the 3 conditions.