Rational beliefs

To the extent that a belief is rational, it ought to be held, other things being equal; irrational beliefs should not be held. From traditional epistemological perspectives, the obligation here is narrow, concerning only good reasons for acceptance that constitute sufficient justification or warrant. Recent epistemological trends broaden the viewpoint to include also practical considerations that enter into other rational decisions, such as best use of the agent’s limited resources.

A related but weaker conception of rationality appears in philosophy of mind as a necessary coherence requirement on personal identity – roughly, ‘No rationality, no agent’. Such agent-constitutive rationality standards are more lenient than normative epistemic standards, since agents’ belief sets can and often do fall short of epistemically uncriticizable rationality without the agents thereby ceasing to qualify as having minds.

Finally, at the widest perspective, long-standing sceptical lines of challenge to rationality of the entire structure of human belief-forming procedures conclude that we can never have the slightest good reason to accept even our most central beliefs. Recent approaches that ‘naturalize’ epistemology into a branch of science tend to exclude such general doubts as insignificant or meaningless; but if distinctively philosophical questions in fact do not fully reduce to regular scientific ones, sceptical-type rationality challenges may instead remain a permanent part of the human condition.