Why is science so rare and faith so common in human history? Traditional cultures persist because it is subjectively rational for each maturing child to defer to the unanimous beliefs of his elders, regardless of any personal doubts. Science is possible only when individuals promote new theories (which will probably be proven false) and forgo the epistemic advantages of accepting established views (which are more likely to be true). Hence, progressive science must rely upon the epistemic altruism of experimental thinkers, (...) while traditions of faith depend on the epistemic self-interest of their followers. (shrink)

It is obvious that we would not want to demand that an agent' s beliefs at different times exhibit the same sort of consistency that we demand from an agent' s simultaneous beliefs; there' s nothing irrational about believing P at one time and not-P at another. Nevertheless, many have thought that some sort of coherence or stability of beliefs over time is an important component of epistemic rationality.

Given common priors, no agent can publicly estimate a non-zero sign for the difference between his estimate and another agent’s future estimate. Thus rational agents cannot publicly anticipate the direction in which other agents will disagree with them.  2002 Elsevier Science B.V. All rights reserved.

It is argued that we need a richer version of Bayesian decision theory, admitting both subjective and objective probabilities and providing rational criteria for choice of our prior probabilities. We also need a theory of tentative acceptance of empirical hypotheses. There is a discussion of subjective and of objective probabilities and of the relationship between them, as well as a discussion of the criteria used in choosing our prior probabilities, such as the principles of indifference and of maximum entropy, and (...) the simplicity ranking of alternative hypotheses. (shrink)

A pluralistic scientific method is one that incorporates a variety of points of view in scientific inquiry. This paper investigates one example of pluralistic method: the use of weighted averaging in probability estimation. I consider two methods of weight determination, one based on disjoint evidence possession and the other on track record. I argue that weighted averaging provides a rational procedure for probability estimation under certain conditions. I consider a strategy for calculating ‘mixed weights’ which incorporate mixed information about agent (...) credibility. I address various objections to the weighted averaging technique and conclude that the technique is a promising one in various respects. (shrink)

Why is common priors are implicit or explicit in the vast majority of the differential information literature in economics and game theory? Why has the economic community been unwilling, in practice, to accept and actually use the idea of truly personal probabilities in much the same way that it did accept the idea of personal utility functions? After all, in, both the utilities and probabilities are derived separately for each decision maker. Why were the utilities accepted as personal, and the (...) probabilities not? (shrink)

Consider two agents who want to be Bayesians with a common prior, but who cannot due to computational limitations. If these agents agree that their estimates are consistent with certain easy-to-compute consistency constraints, then they can agree to disagree about any random variable only if they also agree to disagree, to a similar degree and in a stronger sense, about an average error. Yet average error is a state-independent random variable, and one agent's estimate of it is also agreed to (...) be state-independent. Thus suggests that disagreements are not fundamentally due to differing information about the state of the world. (shrink)

If voters accord evidentiary value to one another's reports, revising their own views in the light of them as Bayesian rationality requires, then even relatively small electoral majorities ought to prove rationally compelling and opposition ought rationally to vanish. For democratic theory, that is a jarring result. While there are no resources for avoiding that result within the Bayesian model itself, there are various aspects of the political process lying outside that model which do serve to underwrite the rationality of (...) persistent opposition to majority opinion. Key Words: Bayesian rationality • consensus • political opposition. (shrink)

In standard belief models, priors are always common knowledge. This prevents such models from representing agents’ probabilistic beliefs about the origins of their priors. By embedding standard models in a larger standard model, however, pre-priors can describe such beliefs. When an agent’s prior and pre-prior are mutually consistent, he must believe that his prior would only have been different in situations where relevant event chances were different, but that variations in other agents’ priors are otherwise completely unrelated to which events (...) are how likely. Due to this, Bayesians who agree enough about the origins of their priors must have the same priors. (shrink)