Probability is the mind, and beliefs are probabilities. It is perfectly rational to assign different probabilities to the same event given that you have different information about it (because probabilities are statements about your lack of information, not inherent properties of the event in question). In your example, someone who read the newspaper and did not know about the misprint has different information about who won the game than somebody who knows that there WAS a misprint; therefore, even if both apply the methods of epistemic rationality, they are bound to assign different probability to the event that United won i.e. they end up with different beliefs. In other words, the function for determining if a given agent’s belief is rational doesn’t just take an argument for the event it refers to, but also needs a parameter for the available information the agent has about said event.
Hence, you are confused because you are talking about situations with different states of information, where different beliefs about the same event may be rational. The quote is talking about single situation with a single state of information where somebody still speaks of the “rational” belief being X while the “true” belief is Y.
Probability is the mind, and beliefs are probabilities. It is perfectly rational to assign different probabilities to the same event given that you have different information about it (because probabilities are statements about your lack of information, not inherent properties of the event in question). In your example, someone who read the newspaper and did not know about the misprint has different information about who won the game than somebody who knows that there WAS a misprint; therefore, even if both apply the methods of epistemic rationality, they are bound to assign different probability to the event that United won i.e. they end up with different beliefs. In other words, the function for determining if a given agent’s belief is rational doesn’t just take an argument for the event it refers to, but also needs a parameter for the available information the agent has about said event.
Hence, you are confused because you are talking about situations with different states of information, where different beliefs about the same event may be rational. The quote is talking about single situation with a single state of information where somebody still speaks of the “rational” belief being X while the “true” belief is Y.