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Counterfactual
Counterfactual conditionals (also ''contrafactual'', ''subjunctive'' or ''X-marked'') are conditional sentences which discuss what would have been true under different circumstances, e.g. "If Peter believed in ghosts, he would be afraid to be here." Counterfactuals are contrasted with indicatives, which are generally restricted to discussing open possibilities. Counterfactuals are characterized grammatically by their use of fake tense morphology, which some languages use in combination with other kinds of morphology including aspect and mood. Counterfactuals are one of the most studied phenomena in philosophical logic, formal semantics, and philosophy of language. They were first discussed as a problem for the material conditional analysis of conditionals, which treats them all as trivially true. Starting in the 1960s, philosophers and linguists developed the now-classic possible world approach, in which a counterfactual's truth hinges on its consequent holding at certain po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counterfactual Conditional
Counterfactual conditionals (also ''contrafactual'', ''subjunctive'' or ''X-marked'') are conditional sentences which discuss what would have been true under different circumstances, e.g. "If Peter believed in ghosts, he would be afraid to be here." Counterfactuals are contrasted with indicatives, which are generally restricted to discussing open possibilities. Counterfactuals are characterized grammatically by their use of fake tense morphology, which some languages use in combination with other kinds of morphology including aspect and mood. Counterfactuals are one of the most studied phenomena in philosophical logic, formal semantics, and philosophy of language. They were first discussed as a problem for the material conditional analysis of conditionals, which treats them all as trivially true. Starting in the 1960s, philosophers and linguists developed the now-classic possible world approach, in which a counterfactual's truth hinges on its consequent holding at certai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Causal Model
In metaphysics, a causal model (or structural causal model) is a conceptual model that describes the causal mechanisms of a system. Several types of causal notation may be used in the development of a causal model. Causal models can improve study designs by providing clear rules for deciding which independent variables need to be included/controlled for. They can allow some questions to be answered from existing observational data without the need for an interventional study such as a randomized controlled trial. Some interventional studies are inappropriate for ethical or practical reasons, meaning that without a causal model, some hypotheses cannot be tested. Causal models can help with the question of ''external validity'' (whether results from one study apply to unstudied populations). Causal models can allow data from multiple studies to be merged (in certain circumstances) to answer questions that cannot be answered by any individual data set. Causal models have found ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Lewis (philosopher)
David Kellogg Lewis (September 28, 1941– October 14, 2001) was an American philosopher. Lewis taught briefly at UCLA and then at Princeton University from 1970 until his death. He is closely associated with Australia, whose philosophical community he visited almost annually for more than 30 years. Lewis made significant contributions in philosophy of mind, philosophy of probability, epistemology, philosophical logic, aesthetics, philosophy of mathematics, philosophy of time and philosophy of science. In most of these fields he is considered among the most important figures of recent decades. Lewis is most famous for his work in metaphysics, philosophy of language and semantics, in which his books ''On the Plurality of Worlds'' (1986) and ''Counterfactuals'' (1973) are considered classics. His works on the logic and semantics of counterfactual conditionals are broadly used by philosophers and linguists along with a competing account from Robert Stalnaker; together the Stal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conditional Sentence
A conditional sentence is a sentence in a natural language that expresses that one thing is contingent on another, e.g., "If it rains, the picnic will be cancelled." They are so called because the impact of the sentence’s main clause is ''conditional'' on a subordinate clause. A full conditional thus contains two clauses: the subordinate clause, called the ''antecedent'' (or ''protasis'' or ''if-clause''), which expresses the condition, and the main clause, called the ''consequent'' (or ''apodosis'' or ''then-clause'') expressing the result. To form conditional sentences, languages use a variety of grammatical forms and constructions. The forms of verbs used in the antecedent and consequent are often subject to particular rules as regards their tense, aspect, and mood. Many languages have a specialized type of verb form called the conditional mood – broadly equivalent in meaning to the English "would (do something)" – for use in some types of conditional sentences. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Material Conditional
The material conditional (also known as material implication) is a binary operation commonly used in logic. When the conditional symbol \to is interpreted as material implication, a formula P \to Q is true unless P is true and Q is false. Material implication is used in all the basic systems of classical logic as well as some nonclassical logics. It is assumed as a model of correct conditional reasoning within mathematics and serves as the basis for commands in many programming languages. However, many logics replace material implication with other operators such as the strict conditional and the variably strict conditional. Due to the paradoxes of material implication and related problems, material implication is not generally considered a viable analysis of conditional sentences in natural language. Notation In logic and related fields, the material conditional is customarily notated with an infix operator \to. The material conditional is also notated using the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Possible World
A possible world is a complete and consistent way the world is or could have been. Possible worlds are widely used as a formal device in logic, philosophy, and linguistics in order to provide a semantics for intensional and modal logic. Their metaphysical status has been a subject of controversy in philosophy, with modal realists such as David Lewis arguing that they are literally existing alternate realities, and others such as Robert Stalnaker arguing that they are not. Logic Possible worlds are one of the foundational concepts in modal and intensional logics. Formulas in these logics are used to represent statements about what ''might'' be true, what ''should'' be true, what one ''believes'' to be true and so forth. To give these statements a formal interpretation, logicians use structures containing possible worlds. For instance, in the relational semantics for classical propositional modal logic, the formula \Diamond P (read as "possibly P") is actually true if and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indicative Conditional
In natural languages, an indicative conditional is a conditional sentence such as "If Leona is at home, she isn't in Paris", whose grammatical form restricts it to discussing what could be true. Indicatives are typically defined in opposition to counterfactual conditionals, which have extra grammatical marking which allows them to discuss eventualities which are no longer possible. Indicatives are a major topic of research in philosophy of language, philosophical logic, and linguistics. Open questions include which logical operation indicatives denote, how such denotations could be composed from their grammatical form, and the implications of those denotations for areas including metaphysics, psychology of reasoning, and philosophy of mathematics. Formal analyses Early analyses identified indicative conditionals with the logical operation known as the material conditional. According to the material conditional analysis, an indicative "If A then B" is true unless A is true and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indicative Conditionals
In natural languages, an indicative conditional is a conditional sentence such as "If Leona is at home, she isn't in Paris", whose grammatical form restricts it to discussing what could be true. Indicatives are typically defined in opposition to counterfactual conditionals, which have extra grammatical marking which allows them to discuss eventualities which are no longer possible. Indicatives are a major topic of research in philosophy of language, philosophical logic, and linguistics. Open questions include which logical operation indicatives denote, how such denotations could be composed from their grammatical form, and the implications of those denotations for areas including metaphysics, psychology of reasoning, and philosophy of mathematics. Formal analyses Early analyses identified indicative conditionals with the logical operation known as the material conditional. According to the material conditional analysis, an indicative "If A then B" is true unless A is true and B i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subjunctive
The subjunctive (also known as the conjunctive in some languages) is a grammatical mood, a feature of an utterance that indicates the speaker's attitude toward it. Subjunctive forms of verbs are typically used to express various states of unreality, such as wish, emotion, possibility, judgment, opinion, obligation, or action, that has not yet occurred. The precise situations in which they are used vary from language to language. The subjunctive is one of the irrealis moods, which refer to what is not necessarily real. It is often contrasted with the indicative, a realis mood which principally indicates that something is a statement of fact. Subjunctives occur most often, although not exclusively, in subordinate clauses, particularly ''that''-clauses. Examples of the subjunctive in English are found in the sentences "I suggest that you ''be'' careful" and "It is important that she ''stay'' by your side." Indo-European languages Proto-Indo-European The Proto-Indo-European lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grammatical Aspect
In linguistics, aspect is a grammatical category that expresses how a verbal action, event, or state, extends over time. For instance, perfective aspect is used in referring to an event conceived as bounded and unitary, without reference to any flow of time during the event ("I helped him"). Imperfective aspect is used for situations conceived as existing continuously or habitually as time flows ("I was helping him"; "I used to help people"). Further distinctions can be made, for example, to distinguish states and ongoing actions ( continuous and progressive aspects) from repetitive actions ( habitual aspect). Certain aspectual distinctions express a relation between the time of the event and the time of reference. This is the case with the perfect aspect, which indicates that an event occurred prior to but has continuing relevance at the time of reference: "I have eaten"; "I had eaten"; "I will have eaten". Different languages make different grammatical aspectual disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Stalnaker
Robert Culp Stalnaker (born 1940) is an American philosopher who is Laurance S. Rockefeller Professor Emeritus of Philosophy at the Massachusetts Institute of Technology. He is a Fellow of the American Academy of Arts and Sciences and a Corresponding Fellow of the British Academy. Education and career Stalnaker was born on January 22, 1940. He earned his BA from Wesleyan University, and his PhD from Princeton University in 1965. His thesis advisor was Stuart Hampshire, though he was strongly influenced by another faculty member, Carl Hempel. Stalnaker taught briefly at Yale University and the University of Illinois, and then for many years at the Sage School of Philosophy at Cornell University before joining the MIT faculty in 1988. He retired from MIT in 2016. His many students include Jason Stanley, Zoltán Gendler Szábo, and Delia Graff Fara. In 2007, Stalnaker delivered the John Locke Lectures at Oxford University on the topic of "Our Knowledge of the Internal World". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
