## Monday, May 11, 2015

### Quick puzzle

You will be paid oodles of money if and only if your next decision is irrational. What should you do?

(There are standard cases in the literature where you lose a lot unless you become irrational, say by taking an irrationality potion. The case at hand differs significantly from those, because it concerns the next decision. You can't just rationally decide to take an irrationality potion, because doing so would constitute your next decision and that would be rational.)

Heath White said...

Cale said...

That's actually a good answer. More generally, make your own next decision without considering the money in your decision-making process.

Cale said...
This comment has been removed by the author.
Mark Rogers said...

I don't know Cale. That seems to me an infinite regress. It seems to me that the safest course would be to decide that you yourself can make the world a better place.

Cale said...

I don't see why it would be an infinite regress. If we just want a safely irrational decision, though, simply decide to believe the wrong answer for any math problem. Leverage some sense of "rational" other than the one implied (but not stated) in the question.

qwerty said...

To answer your question of what you should do: if you want the money then your next decision should be an irrational one.

How would you go about doing that I don't think it's possible because it seems that you'd have to be irrational to begin with.

Anonymous said...

Contracept.

Alexander R Pruss said...

I like the suggestion that if you're perfectly rational, there is nothing you can do. You could make yourself irrational by taking an irrationality pill or by self-hypnosis, but the decision to do so would be rational. So you're just stuck not getting the payoff.

So there are situations where the perfectly rational don't do as well as the imperfectly rational. You and I could probably just do something crazy.

This in turn puts into question common arguments of the form: "If you follow decision theory D, then in such-and-such circumstances you will do less poorly than someone who doesn't follow D. Thus, D isn't something a perfectly rational agent would follow." For there are cases where the irrational do better than the rational. (This isn't an original remark, just more grist.)

Cale said...

Though, of course, these situations only arise when *other* people are being irrational.

Rob S said...

Since sin is necessarily irrational, it seems as though you ought to get get the money if your next action is murder. Of course, that's not what one 'ought' to do, but it is something that would get you the money.

Would vowing to give all the money away to a random person count?

Alexander R Pruss said...

Depends on the view of rationality.

Dagmara Lizlovs said...

Feel the fear and do it anyway. :-)

Anonymous said...

Surely one’s next act should be to say, “no, thanks” and turn down the offer.
Of course, NiqDan35’s answer is trenchant. If we put them together, we are reminded of the old Russian folktale of Ivan and the Devil.

One day, Ivan was out walking when he met the Devil.
“Make the next thing you do an irrational act,” proclaimed the Devil, “and I will make you rich!”
Ivan thought about this, for he was sorely in need of money. “I have not much in the way of education,” he admitted. “I’m not a professor of philosophy or anything… so I don’t think I know how to be deliberately irrational.”
The Devil dismissed this objection airily. “Nothing could be easier! Don’t think about it to much. In fact the less thinking the better!”
But Ivan paid no heed to the Devil’s encouragement. “In fact,” he continued slowly, “man is a rational animal, is he not? So to act irrationally would be a quintessential violation of Natural Law.”
The Devil scowled. “Where are you getting this? Indeed you have not been studying philosophy lately. Forget about all that, don’t you want the money? You’d be a fool to pass up such easy wealth!”
“I suppose I would,” replied Ivan steadfastly. “No doubt you think me quite unreasonable to pass up the opportunity for riches.”
“That I do!” sputtered the Devil. “In which case,” Ivan retorted, “you owe me untold treasures…”
“Shut up,” said the Devil, and vanished, leaving Ivan not a ruble richer. For he was, after all, a liar since the beginning.

Kevin Megill said...

Doesn't it generate a paradox if I do anything at all (such as asking for the money) with the expectation that I will get the money as a result? After all, it would be irrational for me to expect to get the money. Therefore ...

Anonymous said...

Solution: Your next decision should be rational.

Explanation: Assuming you want to be paid oodles of money, then deciding to do the opposite of what guarantees you the money is the worst strategy to get what you want; in other words, if your next decision is rational, then it's irrational. However, since it's irrational, you'll get the money; indeed you're guaranteed to get it.

Thoughts?