Metaphysical modalities are definable from counterfactual conditionals, and the epistemology of the former is a special case of the epistemology of the latter. In particular, the role of conceivability and inconceivability in assessing claims of possibility and impossibility can be explained as a special case of the pervasive role of the imagination in assessing counterfactual conditionals, an account of which is sketched. Thus scepticism about metaphysical modality entails a more far-reaching scepticism about counterfactuals. The account is used to question the (...) significance of the distinction between a priori and a posteriori knowledge. (shrink)

Conducted 2 experiments with undergraduates which demonstrated that, in a recognition memory task, Ss recognized the negated antecedent and consequent propositions of previously encountered counterfactual conditionals significantly more often than control items, the latter effect being distinctly stronger (Exp I, n = 110). A similar result was obtained for causals related to previously encountered counterfactual conditionals and counterfactual conditionals related to previously encountered causals, the latter being the stronger effect (Exp II, n = 92). Results are discussed in the context (...) of the observation that a counterfactual conditional (a) presupposes the negation of its antecedent proposition, (b) strongly suggests the negation of its consequent proposition, and (c) is intimately related to a causal in which (a) and (b) are conjoined, with (a) taken as the grounds for (b). (PsycINFO Database Record (c) 2000 APA, all rights reserved) (unassigned). (shrink)

We report two new phenomena of deontic reasoning: (1) For conditionals with deontic content such as, "If the nurse cleaned up the blood then she must have worn rubber gloves", reasoners make more modus tollens inferences (from "she did not wear rubber gloves" to "she did not clean up the blood") compared to conditionals with epistemic content. (2) For conditionals in the subjunctive mood with deontic content, such as, "If the nurse had cleaned up the blood then she must have (...) had to wear rubber gloves", reasoners make the same frequency of all inferences as they do for conditionals in the indicative mood with deontic content. In this regard, subjunctive deontics are different from subjunctive epistemic conditionals: reasoners interpret subjunctive epistemic conditionals as counterfactual and they make more negative inferences such as modus tollens from them. The experiments show these two phenomena occur for deontic conditionals that contain the modal auxiliary "must" and ones that do not. We discuss the results in terms of the mental representations of deontic conditionals and of counterfactual conditionals. (shrink)

When people understand a counterfactual such as “if the flowers had been roses, the trees would have been orange trees,” they think about the conjecture, “there were roses and orange trees,” and they also think about its opposite, the presupposed facts. We test whether people think about the opposite by representing alternates, for example, “poppies and apple trees,” or whether models can contain symbols, for example, “no roses and no orange trees.” We report the discovery of an inference‐to‐alternates effect—a tendency (...) to make an affirmative inference that refers to an alternate even from a negative minor premise, for example, “there were no orange trees, therefore there were poppies.” Nine experiments show the inference‐to‐alternates effect occurs in a binary context, but not a multiple context, and for direct and indirect reference; it can be induced and reduced by prior experience with similar inferences, and it also occurs for indicative conditionals. The results have implications for theories of counterfactual conditionals, and of negation. (shrink)

This article presents a fundamental advance in the theory of mental models as an explanation of reasoning about facts, possibilities, and probabilities. It postulates that the meanings of compound assertions, such as conditionals (if) and disjunctions (or), unlike those in logic, refer to conjunctions of epistemic possibilities that hold in default of information to the contrary. Various factors such as general knowledge can modulate these interpretations. New information can always override sentential inferences; that is, reasoning in daily life is defeasible (...) (or nonmonotonic). The theory is a dual process one: It distinguishes between intuitive inferences (based on system 1) and deliberative inferences (based on system 2). The article describes a computer implementation of the theory, including its two systems of reasoning, and it shows how the program simulates crucial predictions that evidence corroborates. It concludes with a discussion of how the theory contrasts with those based on logic or on probabilities. (shrink)

TheConceptual Feature framework predicts that word meaning is represented within a high-dimensional semantic space bounded by weighted contributions of perceptual, affective, and encyclopedic information. The ACF, like latent semantic analysis, is amenable to distance metrics between any two words. We applied predictions of the ACF framework to abstract words using eyetracking via an adaptation of the classical “visual word paradigm”. Healthy adults selected the lexical item most related to a probe word in a 4-item written word array comprising the target (...) and three distractors. The relation between the probe and each of the four words was determined using the semantic distance metrics derived from ACF ratings. Eye movement data indicated that the word that was most semantically related to the probe received more and longer fixations relative to distractors. Importantly, in sets where participants did not provide an overt behavioral response, the fixation rates were nonetheless significantly higher for targets than distractors, closely resembling trials where an expected response was given. Furthermore, ACF ratings which are based on individual words predicted eye fixation metrics of probe-target similarity at least as well as latent semantic analysis ratings which are based on word co-occurrence. The results provide further validation of Euclidean distance metrics derived from ACF ratings as a measure of one facet of the semantic relatedness of abstract words and suggest that they represent a reasonable approximation of the organization of abstract conceptual space. The data are also compatible with the broad notion that multiple sources of information shape the organization of abstract concepts. While the adapted “VWP” is potentially a more metacognitive task than the classical visual world paradigm, we argue that it offers potential utility for studying abstract word comprehension. (shrink)