Tuesday, December 8, 2009

Justification vs. Truth Puzzle

For the purposes of this post, I'm assuming something like the intuitive notion of justification makes sense.

Sometimes people say:

1. "You should believe what's true, and avoid believing what's false."

Other times they say:

2. "You should believe what's justified, and avoid believing what's unjustified."

But prima facie, these are incompatible demands, since there are many true propositions which I am not justified in believing, like statements of the form "Tommorrow's winning lottery number will be ....", and 1 seems to entail that I should believe these claims, while 2 seems to entails that I shouldn't.

Puzzle: Can these two claims be made compatible? What is the relationship between these them?

first pass- Maybe we want to widescope? e.g.
1 ='Should[(Ax) Believe(x) <--> Expresses-a-Truth(x)]
2 ='Should[(Ax) Believe(x) <--> You-are-justified-in-believing(x)]
Though this suggests the conclusion that you should bring it about (by some kind of superhuman feat of evidence gathering?) that you are justified in believing every truth. Which is, maybe, odd.

1 comment:

1. C'mon this isn't that puzzling.

So suppose we bet on the outcome of a roll of the dice. You get 100 bucks if you guess the sum of the dice and give me a blow job. I roll the dice under a cup and ask for your guess. Now supposing you would rather get the money than give me head both of the following statements would be true.

"You should guess the number that is the sum of the dice under the cup."

"You should guess the number 7"

These two statements aren't contradictory even when the number rolled is not 7. One of them makes a claim about the desired outcome while the other tells you what procedure would you most likely to achieve that outcome.

Now of course, and perhaps this is what you are really trying to ask, one can ask what makes one hypothesis more likely than another. However, that's just another way of asking for a solution to the problem of induction. You're well aware of what I think about induction but in either case once you grant certain background beliefs about the probability of various claims being true I don't see any additional puzzile here.