Raven Paradox / Hempel's Paradox
Version 1.0.0 · Updated 2026-07-30
CORE DEFINITION
"All ravens are black" is logically equivalent to "All non-black things are not ravens." Therefore, seeing a green apple (non-black, non-raven) logically increases the credibility of "All ravens are black." This is intuitively absurd. Scaffold role: The blind spot of induction. It reminds us that mere accumulation of data (seeing green apples), while logically valid, may be ineffective noise in actual cognition. Verifying a theory requires "ravens" (relevant samples), not an endless stream of "non-ravens" (irrelevant samples).
SCAFFOLDING EFFECT
Reduce cognitive load
The blind spot of induction. It reminds us that mere accumulation of data (seeing green apples), while logically valid, may be ineffective noise in actual cognition. Verifying a theory requires "ravens" (relevant samples), not an endless stream of "non-ravens" (irrelevant samples).
Anchor fast decisions
Hempel proposed that the inductive statement confirming "All ravens are black" has a logically equivalent proposition "All non-black things are not ravens," which can also be confirmed by any green apple (non-black and non-raven), so irrelevant samples logically support the original hypothesis. The mechanism is: the conflict between the classical Nicod's criterion and the equivalence condition exposes the gap between "relevance of evidence" and "logical confirmation."
MINIMUM ACTION
In progress 0/4Practice this model in one real situation:
account_treeGenealogyexpand_more
menu_bookReferencesexpand_more
Source support: Explicit
- zh.wikipedia.orghttps://zh.wikipedia.org/wiki/%E4%B9%8C%E9%B8%A6%E6%82%96%E8%AE%BAverified
PRIVATE NOTES · Only visible to you
SAVED Q&A
ENTRY Q&A · Private saving available
Ask with a clear boundary
thinkingmodels answers from published entry context only.
Your question is sent to thinkingmodels. The answer uses public entry context only.
RELATED MODELS