Counterfactual conditional

Examples An example of the difference between indicative and counterfactual conditionals is the following English minimal pair: • Indicative conditional: If Sally owns a donkey, then she rides it. • Simple past counterfactual: If Sally owned a donkey, she would ride it. These conditionals differ in both form and meaning. The indicative conditional uses the present tense form "owns" and therefore conveys that the speaker is agnostic about whether Sally in fact owns a donkey. The counterfactual example uses the fake tense form "owned" in the "if" clause and the past-inflected modal "would" in the "then" clause. As a result, it conveys that Sally does not in fact own a donkey. English has several other grammatical forms whose meanings are sometimes included under the umbrella of counterfactuality. One is the past perfect counterfactual, which contrasts with indicatives and simple past counterfactuals in its use of pluperfect morphology: • Past perfect counterfactual: If it had been raining yesterday, then Sally would have been inside. Another kind of conditional uses the form "were", generally referred to as the irrealis or subjunctive form. • '''Irrealis counterfactual': If it were raining right now, then Sally would be'' inside. Past perfect and irrealis counterfactuals can undergo conditional inversion: • Had it rained, Sally would have been inside. • Were it raining, Sally would be inside. Terminology The term counterfactual conditional is widely used as an umbrella term for the kinds of sentences shown above. However, not all conditionals of this sort express contrary-to-fact meanings. For instance, the classic example known as the "Anderson Case" has the characteristic grammatical form of a counterfactual conditional, but does not convey that its antecedent is false or unlikely. • Anderson Case: If Jones had taken arsenic, he would have shown just exactly those symptoms which he does in fact show. Such conditionals are also widely referred to as subjunctive conditionals, though this term is likewise acknowledged as a misnomer even by those who use it. Many languages do not have a morphological subjunctive (e.g. Danish and Dutch) and many that do have it do not use it for this sort of conditional (e.g. French, Swahili, all Indo-Aryan languages that have a subjunctive). Moreover, languages that do use the subjunctive for such conditionals only do so if they have a specific past subjunctive form. Thus, subjunctive marking is neither necessary nor sufficient for membership in this class of conditionals. Recently the term X-Marked has been proposed as a replacement, evoking the extra marking that these conditionals bear. Those adopting this terminology refer to indicative conditionals as O-Marked conditionals, reflecting their marking. The antecedent of a conditional is sometimes referred to as its "if"-clause or protasis. The consequent of a conditional is sometimes referred to as a "then"-clause or as an apodosis. ==Logic and semantics==

Counterfactuals were first discussed by Nelson Goodman as a problem for the material conditional used in classical logic. Because of these problems, early work such as that of W.V. Quine held that counterfactuals are not strictly logical, and do not make true or false claims about the world. However, in the 1960s and 1970s, work by Robert Stalnaker and David Lewis showed that these problems are surmountable given an appropriate intensional logical framework. Work since then in formal semantics, philosophical logic (especially conditional logic), philosophy of language, and cognitive science has built on this insight, taking it in a variety of different directions. Classic puzzles The problem of counterfactuals According to the material conditional analysis, a natural language conditional, a statement of the form "if P then Q", is true whenever its antecedent, P, is false. Since counterfactual conditionals are those whose antecedents are false, this analysis would wrongly predict that all counterfactuals are vacuously true. Goodman illustrates this point using the following pair in a context where it is understood that the piece of butter under discussion had not been heated. • If that piece of butter had been heated to 150°F, it would have melted. • If that piece of butter had been heated to 150°F, it would not have melted. More generally, such examples show that counterfactuals are not truth-functional. In other words, knowing whether the antecedent and consequent are actually true is not sufficient to determine whether the counterfactual itself is true. • If Caesar had been in command in Korea, he would have used the atom bomb. • If Caesar had been in command in Korea, he would have used catapults. Non-monotonicity Counterfactuals are non-monotonic in the sense that their truth values can be changed by adding extra material to their antecedents. This fact is illustrated by Sobel sequences such as the following: Belief revision 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 formulae, 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. == The grammar of counterfactuality ==

Languages use different strategies for expressing counterfactuality. Some have dedicated counterfactual morphemes, while others recruit morphemes which otherwise express tense, aspect, mood, or a combination thereof. Since the early 2000s, linguists, philosophers of language, and philosophical logicians have intensely studied the nature of this grammatical marking, and it continues to be an active area of study. Fake tense Description In many languages, counterfactuality is marked by past tense morphology. Since these uses of the past tense do not convey their typical temporal meaning, they are called fake past or fake tense. English is one language which uses fake past to mark counterfactuality, as shown in the following minimal pair. In the indicative example, the bolded words are present tense forms. In the counterfactual example, both words take their past tense form. This use of the past tense cannot have its ordinary temporal meaning, since it can be used with the adverb "tomorrow" without creating a contradiction. Palestinian Arabic is another: Formal analyses In formal semantics and philosophical logic, fake past is regarded as a puzzle, since it is not obvious why so many unrelated languages would repurpose a tense morpheme to mark counterfactuality. Proposed solutions to this puzzle divide into two camps: past as modal and past as past. These approaches differ in whether or not they take the past tense's core meaning to be about time. In the past as modal approach, the denotation of the past tense is not fundamentally about time. Rather, it is an underspecified skeleton which can apply either to modal or temporal content. For instance, the particular past as modal proposal of Iatridou (2000), the past tense's core meaning is what is shown schematically below: • The topic x is not the contextually-provided x Depending on how this denotation composes, x can be a time interval or a possible world. When x is a time, the past tense will convey that the sentence is talking about non-current times, i.e. the past. When x is a world, it will convey that the sentence is talking about a potentially non-actual possibility. The latter is what allows for a counterfactual meaning. The past as past approach treats the past tense as having an inherently temporal denotation. On this approach, so-called fake tense is not actually fake. It differs from "real" tense only in how it takes scope, i.e. which component of the sentence's meaning is shifted to an earlier time. When a sentence has "real" past marking, it discusses something that happened at an earlier time; when a sentence has so-called fake past marking, it discusses possibilities that were accessible at an earlier time but may no longer be. Fake aspect Fake aspect often accompanies fake tense in languages that mark aspect. In some languages (e.g. Modern Greek, Zulu, and the Romance languages) this fake aspect is imperfective. In other languages (e.g. Palestinian Arabic) it is perfective. However, in other languages including Russian and Polish, counterfactuals can have either perfective or imperfective aspect. Fake imperfective aspect is demonstrated by the two Modern Greek sentences below. These examples form a minimal pair, since they are identical except that the first uses past imperfective marking where the second uses past perfective marking. As a result of this morphological difference, the first has a counterfactual meaning, while the second does not. This imperfective marking has been argued to be fake on the grounds that it is compatible with completive adverbials such as "in one month": In ordinary non-conditional sentences, such adverbials are compatible with perfective aspect but not with imperfective aspect: ==Psychology==

People engage in counterfactual thinking frequently. Experimental evidence indicates that people's thoughts about counterfactual conditionals differ in important ways from their thoughts about indicative conditionals. Comprehension Participants in experiments were asked to read sentences, including counterfactual conditionals, e.g., "If Mark had left home early, he would have caught the train". Afterwards, they were asked to identify which sentences they had been shown. They often mistakenly believed they had been shown sentences corresponding to the presupposed facts, e.g., "Mark did not leave home early" and "Mark did not catch the train". In other experiments, participants were asked to read short stories that contained counterfactual conditionals, e.g., "If there had been roses in the flower shop then there would have been lilies". Later in the story, they read sentences corresponding to the presupposed facts, e.g., "there were no roses and there were no lilies". The counterfactual conditional primed them to read the sentence corresponding to the presupposed facts very rapidly; no such priming effect occurred for indicative conditionals. They spent different amounts of time 'updating' a story that contains a counterfactual conditional compared to one that contains factual information and focused on different parts of counterfactual conditionals. Reasoning Experiments have compared the inferences people make from counterfactual conditionals and indicative conditionals. Given a counterfactual conditional, e.g., "If there had been a circle on the blackboard then there would have been a triangle", and the subsequent information "in fact there was no triangle", participants make the modus tollens inference "there was no circle" more often than they do from an indicative conditional. Given the counterfactual conditional and the subsequent information "in fact there was a circle", participants make the modus ponens inference as often as they do from an indicative conditional. Psychological accounts Byrne argues that people construct mental representations that encompass two possibilities when they understand, and reason from, a counterfactual conditional, e.g., "if Oswald had not shot Kennedy, then someone else would have". They envisage the conjecture "Oswald did not shoot Kennedy and someone else did" and they also think about the presupposed facts "Oswald did shoot Kennedy and someone else did not". According to the mental model theory of reasoning, they construct mental models of the alternative possibilities. ==See also==