Peter Klein

Peter Klein was an American epistemologist who taught at Rutgers University. Early work defended knowledge against scepticism and developed a defeasibility analysis of knowledge; he is best known for reviving infinitism. Faced with the regress of reasons, he argued that justification requires an infinite, non-repeating chain of available reasons, since both foundationalism and coherentism fail.

Key ideas

• Infinitism: a belief is justified only if there is an infinite, non-repeating series of reasons available for it.
• Foundationalism makes stopping points arbitrary, while coherentism makes reasoning circular.
• Justification comes in degrees and grows as reasons are added, rather than being transmitted from a foundation.
• Knowledge is justified true belief whose justification is not defeated by any further truth.

Major works

• Certainty: A Refutation of Scepticism (1981)
• Human Knowledge and the Infinite Regress of Reasons (1999)

In the conversation

• Debate An infinite chain of reasons is not a defect: the case for infinitism deserves more than a smirk Tomasz Szewczak · 5 replies