Raven paradox

A black raven, and a collection of non-black non-ravens. The raven paradox suggests that both of these images contribute evidence to the supposition that all ravens are black.

The raven paradox, also known as Hempel's paradox, Hempel's ravens, or rarely the paradox of indoor ornithology,^[1] is a paradox arising from the question of what constitutes evidence for the truth of a statement. Observing objects that are neither black nor ravens may formally increase the likelihood that all ravens are black even though, intuitively, these observations are unrelated.

This problem was proposed by the logician Carl Gustav Hempel in the 1940s to illustrate a contradiction between inductive logic and intuition.^[2]

^ Satosi Watanabe (1969). Knowing and Guessing: A Quantitative Study of Inference and Information. New York: Wiley. ISBN 0-471-92130-0. LCCN 68-56165.Sect.4.5.3, p.183
^ Fetzer, James (Winter 2016). "Carl Hempel". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University.

[1] Satosi Watanabe (1969). Knowing and Guessing: A Quantitative Study of Inference and Information. New York: Wiley. ISBN 0-471-92130-0. LCCN 68-56165.Sect.4.5.3, p.183

[2] Fetzer, James (Winter 2016). "Carl Hempel". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University.

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