open question argument

ethics

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July 1, 2026

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The "naturalistic fallacy," as termed by G.E. Moore, is the error of defining "good" as a natural property. Moore's "open-question argument" challenges any attempt to define "good" in terms of something else, whether natural (like pleasure) or supernatural (like divine will). The argument posits that if a definition of "good" were correct, asking "Is X good?" after defining "good" as X would be a meaningless question, akin to asking "Is an unmarried man a bachelor?". This highlights that "good" is a simple, unanalyzable quality. Ethical naturalism, conversely, holds that moral terms can be defined by natural facts.1234

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ethics
Moore and the naturalistic fallacy
”) The “open-question argument,” as it came to be known, was in fact used by Sidgwick and to some extent by the 18th-century intuitionists, but Moore’s statement of it somehow caught the imagination of philosophers during the first half of the 20th century. The upshot was that…
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”) The “open-question argument,” as it came to be known, was in fact used by Sidgwick and to some extent by the 18th-century intuitionists, but Moore’s statement of it somehow caught the imagination of philosophers during the first half of the 20th century. The upshot was that…
Read More