I think the rational is the closest to true you can possibly [edit: justifiably] get from where you are.
Notice that in your example you introduce a third person perspective which is aware of the misprint. From Rob’s perspective the rational is to believe the newspaper. If he knew of the misprint as the third-person perspective seems to, the rational would be not to believe the news paper.
However, to reach a position where you can say “The rational belief is X, but the true belief is Y”, it means you are making this distinction from the same perspective, which you shouldn’t be able to do if you’re defining ‘rational’ as most of us do.
“I think the rational is the closest to true you can possibly get from where you are.”
The truth is the closest you can get to the truth. Suppose Rob reads the newspaper but then believes that City won because their his team and it would make him happy if they won. His belief would be closer to the truth, but it would not be rational.
That can be patched with editing to “the rational is the closest to true you can justifiably get from where you are”.
I’m taking a page from the definition of knowledge as ‘justified true belief’. The belief that his team won would be true but not justified. Just as a broken clock is right twice a day but that still doesn’t make it a reliable time measurement apparatus.
So I can use “unjustifiable” methods to get even closer to the truth? Screw “rationality”, then!
Yes, you can. But with a lower probability. At the limiting case you can add or subtract an epsilon from the ‘rational’ probability assignment and you will be closer to the truth (0.5 - _different_epsilon_) of the time.
This applies to instrumental rationality too. A lucky guess will win you the lottery. An expected utility calculation will not (except when extremely desperate and similarly lucky).
Did you see me mentioning methods anywhere? If a method can get you closer to truth, then that is its justification. But in the example given the method was “it would make him happy if they won”. This is not a reliable method for reaching truth and on average will get you farther from it.
I think the rational is the closest to true you can possibly [edit: justifiably] get from where you are.
Notice that in your example you introduce a third person perspective which is aware of the misprint. From Rob’s perspective the rational is to believe the newspaper. If he knew of the misprint as the third-person perspective seems to, the rational would be not to believe the news paper.
However, to reach a position where you can say “The rational belief is X, but the true belief is Y”, it means you are making this distinction from the same perspective, which you shouldn’t be able to do if you’re defining ‘rational’ as most of us do.
“I think the rational is the closest to true you can possibly get from where you are.”
The truth is the closest you can get to the truth. Suppose Rob reads the newspaper but then believes that City won because their his team and it would make him happy if they won. His belief would be closer to the truth, but it would not be rational.
That can be patched with editing to “the rational is the closest to true you can justifiably get from where you are”.
I’m taking a page from the definition of knowledge as ‘justified true belief’. The belief that his team won would be true but not justified. Just as a broken clock is right twice a day but that still doesn’t make it a reliable time measurement apparatus.
So I can use “unjustifiable” methods to get even closer to the truth? Screw “rationality”, then!
Not consistently, which is the point.
Yes, you can. But with a lower probability. At the limiting case you can add or subtract an epsilon from the ‘rational’ probability assignment and you will be closer to the truth (0.5 - _different_epsilon_) of the time.
This applies to instrumental rationality too. A lucky guess will win you the lottery. An expected utility calculation will not (except when extremely desperate and similarly lucky).
Did you see me mentioning methods anywhere? If a method can get you closer to truth, then that is its justification. But in the example given the method was “it would make him happy if they won”. This is not a reliable method for reaching truth and on average will get you farther from it.