'Negation as failure' is Sakama's gloss, not Stenning & van Lambalgen's own term in their 2001 and 2004 papers

reasoning-psychologylogic-programmingnon-monotonic-logicnegation-as-failureclosed-world-assumptioncognitive-science

Both primary papers by Stenning and van Lambalgen (2001, 45 pp.; 2004, 49 pp. including references) were read in full. The literal AI/logic-programming phrase "negation as failure" does not occur in either text — nor do the variants "negation-as-failure" or "negation by failure". The vocabulary they do use is sparse rather than pervasive, and it is not evenly distributed across the two papers: "closed world" occurs twice in the 2004 paper and three times in the 2001 paper, while "non-monotonic" occurs five times in 2004 (including in its keyword list) and not once in 2001. The non-monotonic framing is therefore a 2004 development, not a constant: "The classical notion of validity may also give way to a non-monotonic notion of validity... One concrete instance of this is so-called 'closed world reasoning', in which one assumes (roughly speaking) that all statements are false which are not forced to be true by the premises." The 2004 reference list also does not cite Clark (1978) or Reiter (1978/1980) — the two papers usually credited for negation-as-failure and the closed-world assumption in logic programming — and neither does the 2001 list; neither paper cites any author named Clark or Reiter in any year.

This narrows a claim the vault inherited at second hand. Sakama (TPLP 2024) attributes "negation as failure" to this lineage when he redescribes it in Answer Set Programming (claim-conditional-reasoning-fallacies-as-closed-world-inference-in-asp, where Reiter is cited directly). The finding here is that the specific negation-as-failure operator is Sakama's translation of S&vL's account into logic-programming terms — layered onto an account these two S&vL papers state in the vocabulary of non-monotonic logic and closed-world reasoning. The two converge on the same underlying move (see claim-stenning-van-lambalgen-two-clause-exception-scheme-not-material-conditional) without the earlier authors naming it that way. This is the scope-limit on claim-stenning-van-lambalgen-model-wason-fallacies-as-closed-world-reasoning and the reason the bridge note claim-logic-programming-account-rivals-probabilistic-account-of-conditional-reasoning should attribute "negation as failure" to Sakama's layer, not S&vL's.

[unverified-mechanism — needs primary] Whether the literal phrase appears in the fuller, later development — the 2005 Cognitive Science suppression-task paper or the 2008 MIT Press book — was not checked this run; those texts were not obtained. See question-verify-stenning-van-lambalgen-closed-world-wason.