Editing Counterfactual conditional (section)

=== Other accounts ===

====Causal models====

{{Further|Causal model#Counterfactuals}}

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The ''causal models framework'' analyzes counterfactuals in terms of systems of [[structural equation model|structural equations]]. In a system of equations, each variable is assigned a value that is an explicit function of other variables in the system. Given such a model, the sentence "''Y'' would be ''y'' had ''X'' been ''x''" (formally, ''X = x'' > ''Y = y'' ) is defined as the assertion: If we replace the equation currently determining ''X'' with a constant ''X = x'', and solve the set of equations for variable ''Y'', the solution obtained will be ''Y = y''. This definition has been shown to be compatible with the axioms of possible world semantics and forms the basis for causal inference in the natural and social sciences, since each structural equation in those domains corresponds to a familiar causal mechanism that can be meaningfully reasoned about by investigators. This approach was developed by [[Judea Pearl]] (2000) as a means of encoding fine-grained intuitions about causal relations which are difficult to capture in other proposed systems.<ref name="Pearl2000">{{Cite book |last=Pearl |first=Judea |title=Causality |publisher=Cambridge University Press |year=2000 }}</ref>

====Belief revision====

{{Further|Belief revision#The Ramsey test}}
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In the [[belief revision]] framework, counterfactuals are treated using a formal implementation of the ''Ramsey test''. In these systems, a counterfactual ''A'' > ''B'' holds if and only if the addition of ''A'' to the current body of knowledge has ''B'' as a consequence. This condition relates counterfactual conditionals to [[belief revision]], as the evaluation of ''A'' > ''B'' can be done by first revising the current knowledge with ''A'' and then checking whether ''B'' is true in what results.  Revising is easy when ''A'' is consistent with the current beliefs, but can be hard otherwise. Every semantics for belief revision can be used for evaluating conditional statements.  Conversely, every method for evaluating conditionals can be seen as a way for performing revision.

====Ginsberg====

Ginsberg (1986) has proposed a semantics for conditionals which assumes that the current beliefs form a set of [[propositional formula]]e, considering the maximal sets of these formulae that are consistent with ''A'', and adding ''A'' to each. The rationale is that each of these maximal sets represents a possible state of belief in which ''A'' is true that is as similar as possible to the original one. The conditional statement ''A'' > ''B'' therefore holds if and only if ''B'' is true in all such sets.<ref name="rev. no. 03011">{{Citation |title=Review of the paper: M. L. Ginsberg, "Counterfactuals," Artificial Intelligence 30 (1986), pp. 35–79 |work=Zentralblatt für Mathematik |pages=13–14 |year=1989 | volume=30 |publisher=FIZ Karlsruhe – Leibniz Institute for Information Infrastructure GmbH | doi=10.1016/0004-3702(86)90067-6 |zbl=0655.03011 | last1=Ginsberg | first1=Matthew L. | s2cid=241535532 |doi-access=free }}.</ref>