Facts and Possibilities: A Model‐Based Theory of Sentential Reasoning

Abstract

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.

The Suppression of Inferences From Counterfactual Conditionals

“…The “fleshed out” set of models can correspond to many different interpretations of if (e.g., Johnson‐Laird & Byrne, 2002). One interpretation is consistent with three possibilities, as Table 2 shows, which are conjunctive—it is possible that she watered the plants and they bloomed, and it is possible that she did not water the plants and they did not bloom, and it is possible that she did not water the plants and they bloomed anyway (e.g., Khemlani, Byrne, & Johnson‐Laird, 2018). They do not think about the possibility ruled out as false, that is, she watered the plants and they did not bloom (e.g., Johnson‐Laird & Byrne, 2002; Espino, Santamaria, & Byrne, 2009).…”

“…The results of the six experiments reported here indicate that most people give precedence to beliefs about additional conditions over beliefs about presupposed facts. The results were predicted by the theory that people combine these beliefs by relying on the simulation of the possibilities that are consistent with them (e.g., Byrne & Johnson‐Laird, 2019; Khemlani et al, 2018).…”

Testing the visual impedance effect in children with and without reading difficulties using a new visual reasoning task

“…This finding agrees with the results of Knauff and Johnson-Laird (2002), showing that the visual impedance effect is present when the premises of the reasoning problems are complex (two opposite adjectives) and can be visualized easily. In general, simple problems, may lead to jumping to conclusions automatically (System I) without considering alternatives and without the opportunity to produce the deductive effect (System II; See Khemlani, Byrne, & Johnson-Laird, 2018).…”

Effect of personality on compound reasoning

“…In this way, the number of mental models takes on a crucial role. According to the model, as the number of possibilities that subjects must represent increases, so does the overload in their working memory (Khemlani, 2018;Khemlani et al, 2012Khemlani et al, , 2014Khemlani et al, , 2017Khemlani et al, , 2018). Consequently, the task becomes more difficult, while both time to resolution and tendency to error increase (Khemlani, 2018;Khemlani et al, 2012Khemlani et al, , 2014Khemlani et al, , 2017Khemlani et al, , 2018.…”

“…While logicist theories emphasize the formal and syntactic aspects of thought, the MMT focuses on the semantic and contextual components (Khemlani, 2018;Macbeth, Razumiejczyk, Crivello, Fioramonti, & Pereyra-Girardi, 2013). The general hypothesis is that people reason by developing mental models of the world (Khemlani, Byrne, & Johnson-Laird, 2018;Johnson-Laird & Ragni, 2019). These models are defined as iconic representations of the world (Johnson-Laird, 2006).…”