Are people rational? This question was central to Greek thought and has been at the heart of psychology and philosophy for millennia. This book provides a radical and controversial reappraisal of conventional wisdom in the psychology of reasoning, proposing that the Western conception of the mind as a logical system is flawed at the very outset. It argues that cognition should be understood in terms of probability theory, the calculus of uncertain reasoning, rather than in terms of logic, the calculus (...) of certain reasoning. (shrink)

Classic work by one of the most brilliant figures in post-war analytic philosophy.

According to Aristotle, humans are the rational animal. The borderline between rationality and irrationality is fundamental to many aspects of human life including the law, mental health, and language interpretation. But what is it to be rational? One answer, deeply embedded in the Western intellectual tradition since ancient Greece, is that rationality concerns reasoning according to the rules of logic – the formal theory that specifies the inferential connections that hold with certainty between propositions. Piaget viewed logical reasoning as defining (...) the end-point of cognitive development; and contemporary psychology of reasoning has focussed on comparing human reasoning against logical standards. (shrink)

In this study on deduction, the authors argue that people reason by imagining the relevant state of affairs, ie building an internal model of it, formulating a tentative conclusion based on this model and then searching for alternative models.

What we want to be true about ordinary indicative conditionals seems to be more than we can possibly get: there just seems to be no good way to assign truth-conditions to ordinary indicative conditionals. Some take this argument as reason to make our wantings more modest. Others take it to show that indicative conditionals don't have truth-conditions in the first place. But we have overlooked two possibilities for assigning truth-conditions to indicatives. What's more, those possibilities deliver what we want and (...) turn out to be equivalent. CiteULike Connotea Del.icio.us Digg Reddit Technorati What's this? (shrink)

The study of deductive reasoning has been a major paradigm in psychology for approximately the past 40 years. Research has shown that people make many logical errors on such tasks and are strongly influenced by problem content and context. It is argued that this paradigm was developed in a context of logicist thinking that is now outmoded. Few reasoning researchers still believe that logic is an appropriate normative system for most human reasoning, let alone a model for describing the process (...) of human reasoning, and many use the paradigm principally to study pragmatic and probabilistic processes. It is suggested that the methods used for studying reasoning be reviewed, especially the instructional context, which necessarily defines pragmatic influences as biases. (shrink)

I present a puzzle concerning counterfactual reasoning and argue that it should be solved by giving up the principle of substitution for logical equivalents.

A leading scholar in the psychology of thinking and reasoning argues that the counterfactual imagination—the creation of "if only" alternatives to ...

We present a meta-analytic review on the processing of negations in conditional reasoning about affirmation problems (Modus Ponens: “MP”, Affirmation of the Consequent “AC”) and denial problems (Denial of the Antecedent “DA”, and Modus Tollens “MT”). Findings correct previous generalisations about the phenomena. First, the effects of negation in the part of the conditional about which an inference is made, are not constrained to denial problems. These inferential-negation effects are also observed on AC. Second, there generally are reliable effects of (...) a negation in the clause referred to by the categorical premise, and these referred-negation effects are constrained to the logically fallacious AC and DA inferences. All findings are presented and discussed in relation to contemporary mental model (MM) and mental logic (ML) theories. It is argued that a double-negation elimination hypothesis provides a sufficient explanation of inferential-negation effects within both MM theory and ML theory, if the latter is extended by a validating search for counter examples. Both MM and ML theories adhere to a processing scheme that allows them to incorporate an account of referred-negation effects based on the thesis that counter-example frequency is modulated by the scope of a contrast class delineated by a false affirmative. We conclude that MM and ML theories provide adequate processing schemes to accommodate for the explanatory hypotheses, at least in principle. In practice, both approaches remain equivocal as regards the connectivity and interactivity with long-term memory knowledge invoked in generating, manipulating, and testing the mental representations of negative state of affairs. (shrink)

Reports on beliefs, desires, and other attitudes continue to raise foundational questions about linguistic meaning and the pragmatics of utterance interpretation. There is a strong intuition that an attitude report like ‘John believes that Mary smokes’ can simply convey the singular proposition that the individual Mary is believed by John to have the property of smoking. Yet, there is also a strong intuition that ‘Lois believes that Superman can fly’ can additionally convey how an individual is represented . Cases of (...) this sort can be generated with any name in a suitable context . It is far from settled how this should be explained. I propose the Open Instruction Theory , according to which the linguistic meaning of attitude report sentences consists in instructions to create mental models, where those instructions leave open, depending on the state of the discourse, the possibility of singular interpretations as well as of complex interpretations including information about ways of representing. The account makes precise the idea that attitude report sentences with proper names are semantically nonspecific , rather than indexical , yielding predictions about syntactic constraints on interpretation. On this view, linguistic meaning itself does not provide determinate propositions. Since Gricean pragmatics requires determinate propositions as input, I propose new principles of pragmatics for literal utterance interpretation that do not require them but remain strongly constrained by linguistic meaning. The core principle is “inference to the most responsive interpretation.” Roughly, among the range of literal interpretations allowed by linguistic meaning, the listener generates the one that most fully answers the background question she seeks to answer by engaging in discourse. The pragmatics of literal utterance interpretation is the pragmatics of interpreting potential answers, even if communicative intention may be more important for conversational implicature. The account predicts cases in which our interpretations differ from what we would take the speaker to have had in mind. Singular interpretations of attitude reports have a special status as default interpretations. I suggest some advantages of OIT over indexicalist, DRT, and free enrichment theories. I argue that to the extent that we have to go beyond a strict principle of linguistic constraint , we should aim toward a principle of psychological constraint. (shrink)