I propose a way of thinking aboout content, and a related way of thinking about ontological commitment. (This is part of a series of four closely related papers. The other three are ‘On Specifying Truth-Conditions’, ‘An Actualist’s Guide to Quantifying In’ and ‘An Account of Possibility’.).

InSuppose and Tell, Williamson makes a new and original attempt to defend the material conditional account of indicative conditionals. His overarching argument is that this account offers the best explanation of the data concerning how people evaluate and use such conditionals. We argue that Williamson overlooks several important alternative explanations, some of which appear to explain the relevant data at least as well as, or even better than, the material conditional account does. Along the way, we also show that Williamson (...) errs at important junctures about what exactly the relevant data are. (shrink)

The paper reviews a number of approaches for handling restricted quantification in relevant logic, and proposes a novel one. This proceeds by introducing a novel kind of enthymematic conditional.

There is a new Bayesian, or probabilistic, paradigm in the psychology of reasoning, with new psychological accounts of the indicative conditional of natural language. In psychological experiments in this new paradigm, people judge that the probability of the indicative conditional, P(if A then C), is the conditional probability of C given A, P(C | A). In other experiments, participants respond with what has been called the 'de- fective' truth table: they judge that if A then C is true when A (...) holds and C holds, is false when A holds and C does not, and is neither true nor false when A does not hold. We argue that these responses are not 'defective' in any negative sense, as many psychologists have implied. We point out that a number of normative researchers, including de Finetti, have proposed such a table for various coherent interpretations of the third value. We review the relevant general tables in the normative literature, in which there is a third value for A and C and the logically compound forms of the natural language conditional, negation, conjunction, disjunction, and the material conditional. We describe the results of an experiment on which of these tables best describes ordinary people's judgements when the third value is interpreted as indicating uncertainty. (shrink)

This paper explores allowing truth value assignments to be undetermined or "partial" and overdetermined or "inconsistent", thus returning to an investigation of the four-valued semantics that I initiated in the sixties. I examine some natural consequence relations and show how they are related to existing logics, including ukasiewicz's three-valued logic, Kleene's three-valued logic, Anderson and Belnap's relevant entailments, Priest's "Logic of Paradox", and the first-degree fragment of the Dunn-McCall system "R-mingle". None of these systems have nested implications, and I investigate (...) twelve natural extensions containing nested implications, all of which can be viewed as coming from natural variations on Kripke's semantics for intuitionistic logic. Many of these logics exist antecedently in the literature, in particular Nelson 's "constructible falsity". (shrink)

Temporal necessity and the subjunctive conditional appear to be related by the principle of Past Predominance, according to which past similarities and differences take priority over future similarities and differences in determining the comparative similarity of alternative possible histories with respect to the present moment. R. H. Thomason and Anil Gupta have formalized Past Predominance in a semantics that combines selection functions with branching time; in this paper I show that Past Predominance can be formalized and axiomatized using ordinary possible (...) worlds semantics (without branching time). (shrink)

Anaphoric deflationism is a prosententialist account of the use of “true.” Prosentences are, for sentences, the equivalent of what pronouns are for nouns: as pronouns refer to previously introduced nouns, so prosentences like “that’s true” inherit their content from previously introduced sentences. This kind of deflationism concerning the use of “true” (especially in Brandom’s version) is an explanation in terms of anaphora; the prosentence depends anaphorically on the sentence providing its content. A relevant implication of this theory is that “true” (...) is not understood as a predicate and that truth is not a property. Primitivism, defended by Frege, Moore, and Davidson, is associated with two ideas: (1) that truth is a primitive and central trait of our conceptual system and (2) that truth, as such, cannot be defined. This second claim can be called “negative primitivism,” and it especially points out the facts about the “indefinability” of truth generally advocated by primitivists. In what follows, a connection is established between the deflationist’s rejection of the predicate and of the property and facts (and primitivist ideas) about the indefinability of truth. This connection establishes a common framework to lend further explanatory power to both options. According to the resulting view, this indefinability can explain the appeal and soundness of a deflationist dismissal of predicates and properties dealing with truth. (shrink)

The representation of propositional attitudes (beliefs, desires, etc.) and the analysis of natural-language, propositional-attitude reports presents difficult problems for cognitive science and artificial intelligence. In particular, various representational approaches to attitudes involve the incorrect “imputation,” to cognitive agents, of the use of artificial theory-laden notions. Interesting cases of this problem are shown to occur in several approaches to attitudes. The imputation problem is shown to arise from the way that representational approaches explicate properties and relationships, and in particular from the (...) way they explicate propositional attitudes themselves. Another factor contributing to imputation is the compositional nature of typical semantic approaches to propositional-attitude reports. Some strategies for avoiding undesirable imputation are examined. One of the main conclusions is that the importance of imputations that arise in a representation scheme depends strongly on the use to which the scheme is put -- on whether, for instance, the scheme is used as part of a formal, objective account of natural language, or is used rather as a representational tool within an agent. (shrink)

entry for the Entry for the Stanford Encyclopedia of Philosophy, 2007.

This article begins by outlining some of the history—beginning with brief remarks of Quine's—of work on conditional assertions and conditional events. The upshot of the historical narrative is that diverse works from various starting points have circled around a nexus of ideas without convincingly tying them together. Section 3 shows how ideas contained in a neglected article of de Finetti's lead to a unified treatment of the topics based on the identification of conditional events as the objects of conditional bets. (...) The penultimate section explores some of the consequences of the resulting logic of conditional events while the last defends it. (shrink)

Psychological research on people’s understanding of natural language connectives has traditionally used truth table tasks, in which participants evaluate the truth or falsity of a compound sentence given the truth or falsity of its components in the framework of propositional logic. One perplexing result concerned the indicative conditional if A then C which was often evaluated as true when A and C are true, false when A is true and C is false but irrelevant“ (devoid of value) when A is (...) false (whatever the value of C). This was called the “psychological defective table of the conditional.” Here we show that far from being anomalous the “defective” table pattern reveals a coherent semantics for the basic connectives of natural language in a trivalent framework. This was done by establishing participants’ truth tables for negation, conjunction, disjunction, conditional, and biconditional, when they were presented with statements that could be certainly true, certainly false, or neither. We review systems of three-valued tables from logic, linguistics, foundations of quantum mechanics, philosophical logic, and artificial intelligence, to see whether one of these systems adequately describes people’s interpretations of natural language connectives. We find that de Finetti’s (1936/1995) three-valued system is the best approximation to participants’ truth tables. (shrink)

Defenders of the prosentential theory of truth claim that the English language contains prosentences which function analogously to their better known cousins – pronouns. Statements such as ‘That is true’ or ‘It is true’, they claim, inherit their content from antecedent statements, just as pronouns inherit their reference from antecedent singular terms. Prosentential theorists claim that the content of these prosentences is exhausted by the content of their antecedents. They then use the notion of the inheritance of content from an (...) antecedent to explain the various functions of the predicate ‘. . . is true’. Defenders of the prosentential theory of truth are mistaken, I claim, in thinking that in order to oppose the view that ‘. . . is true’ is used to ascribe a substantive truth property to propositions they need to claim that no uses of ‘. . . is true’ ever attribute any property. I identify an ‘attributive’ use of prosentences in which reliability is implicitly attributed to a subject. I then use the capacity of prosentences to serve as implicit attributions of reliability as a basis for explicating the logical structure of explicit attributions of reliability. The identification of an attributive use of prosentences does not constitute a fundamental change in the prosentential theory. (shrink)

This paper presents, in a more general setting, a simple approach to ‘relevant restricted generalizations’ advanced in previous work. After reviewing some desiderata for restricted generalizations, I present the target route towards achieving the desiderata. An objection to the approach, due to David Ripley, is presented, followed by three brief replies, one from a dialetheic perspective and the others more general.

In this paper the informativeness account of assertion (Pagin in Assertion. Oxford University Press, Oxford, 2011) is extended to account for inference. I characterize the conclusion of an inference as asserted conditionally on the assertion of the premises. This gives a notion of conditional assertion (distinct from the standard notion related to the affirmation of conditionals). Validity and logical validity of an inference is characterized in terms of the application of method that preserves informativeness, and contrasted with consequence and logical (...) consequence, that is defined in terms of truth preservation. The proposed account is compared with that of Prawitz (Logica yearbook 2008, pp. 175-192. College Publications, London, 2009). (shrink)

Anaphoric deflationism is a kind of prosententialist account of the use of “true.” It holds that “true” is an expressive operator and not a predicate. In particular, “is true” is explained as a “prosentence.” Prosentences are, for sentences, the equivalent of what pronouns are for nouns: As pronouns refer to previously introduced nouns, so prosentences like “that’s true” inherit their semantic content from previously introduced sentences. So, if Jim says, “The candidate is going to win the election,” and Bill replies (...) “that’s true,” the real meaning of Bill’s statement is “It is true that the candidate is going to win the election.” This kind of prosententialist deflationism around the use of “true,” especially in Robert Brandom’s version, is an explanation given in terms of anaphora. The prosentence is an anaphoric dependent of the sentence providing its content. Båve (Philosophical Studies, 145, 297-310. 2009) argued that the anaphoric account is not as general as prosententialists claim, and that the analogy between prosentences and pronouns is explanatorily idle because it does not do any real explanatory work. The two criticisms are connected: The lack of unity within the anaphoric theory can be used to show its poor explanatory value. The plurality of uses of “is true” exceeds the anaphoric account indeed. Therefore, prosententialism is just a superficial re-description and the real work is done by means of more general semantic terms, namely “semantic equivalence and consequence” between “p” and ““p” is true.” I analyze Båve’s arguments and highlight that he fails to acknowledge the importance of a pragmatic and expressive dimension explained by the anaphoric account, a dimension that semantic “equivalence” and “consequence” are not capable of explaining. I then show that the anaphoric account can actually explain semantic equivalence and consequence, and this is crucial because equivalence and consequence do not explain anaphoric dependence. This reverses the allegation of generality: The anaphoric account is more general. Again, the cases typically used to defend prosententialism, if correctly described, show a unitary structure: They are all versions of lazy anaphoric dependence. Therefore, the unifying principle performing the explanation here is lazy anaphora. (shrink)

Drawing upon Martin-Löf’s semantic framework for his constructive type theory, semantic values are assigned also to natural-deduction derivations, while observing the crucial distinction between consequence among propositions and inference among judgements. Derivations in Gentzen’s format with derivable formulae dependent upon open assumptions, stand, it is suggested, for proof-objects, whereas derivations in Gentzen’s sequential format are proof-acts.

Generalized Quantifier Theory defines superlative quantifiers at most n and at least n as truth-conditionally equivalent to comparative quantifiers fewer than n+1 and more than n \1. It has been demonstrated, however, that this standard theory cannot account for various linguistic differences between these two types of quantifiers. In this paper I discuss how the distinction between assertibility and truth-conditions can be applied to explain this phenomenon. I draw a parallel between the assertibility of disjunctions and superlative quantifiers, and argue (...) that those assertibility conditions are essentially modal. I use epistemic logic to formalize the assertibility conditions and revisit some of the linguistic puzzles related to superlative quantification. (shrink)

Intervals in boolean algebras enter into the study of conditional assertions (or events) in two ways: directly, either from intuitive arguments or from Goodman, Nguyen and Walker's representation theorem, as suitable mathematical entities to bear conditional probabilities, or indirectly, via a representation theorem for the family of algebras associated with de Finetti's three-valued logic of conditional assertions/events. Further representation theorems forge a connection with rough sets. The representation theorems and an equivalent of the boolean prime ideal theorem yield an algebraic (...) completeness theorem for the three-valued logic. This in turn leads to a Henkin-style completeness theorem. Adequacy with respect to a family of Kripke models for de Finetti's logic, Łukasiewicz's three-valued logic and Priest's Logic of Paradox is demonstrated. The extension to first-order yields a short proof of adequacy for Körner's logic of inexact predicates. (shrink)

I defend the correspondence theory of truth, according to which a statement’s truth consists in a relation of correspondence with extralinguistic fact. There are well-known objections to this view, which I consider and rebut, and also important rival accounts, principal among which are so-called deflationist theories and epistemic theories. Epistemic theories relate the concept of truth to our state of knowledge, but fail, I argue, to respect the crucial distinction between a criterion of truth and the meaning of truth: the (...) view that one cannot do semantics, or metaphysics, without addressing epistemic issues is rejected by this work. Against epistemic theories, I illustrate how truth is independent of epistemic considerations. Deflationism is the more popular of the rival accounts and has gained considerable momentum over the past two decades. It is therefore dealt with in greater detail by this work. Deflationist theories exploit the paradigmatic ‘“Snow is white” is true iff snow is white’ biconditional to argue for an insubstantialist account, according to which truth is conservative with respect to non-semantical facts. On this view, truth’s raison d’être is merely to perform the useful expressive function of generalising over possibly infinite sets of assertions. Against deflationist theories, I claim that the work done by Jeffrey Ketland and Stewart Shapiro conclusively demonstrates how truth is informationally additive over non-semantic facts, while deflationism itself is also an excessively impoverishing theory, inadequate to the tasks it purports to accomplish. This work also defends the thesis that Alfred Tarski’s well-known theory of truth is an authentic correspondence theory. To say this is to say that the clauses of a Tarskian truth-definition can be interpreted in terms of a relation of correspondence that holds between true sentences and the states of affairs they describe. I provide a precise account of what the correspondence in question consists in, claiming that true sentences are homomorphic images of facts, i.e. a true sentence represents, in a form-preserving manner, the truth-making facts in it. This gives precise expression to Wittgenstein’s thesis that true sentences picture the world. (shrink)