Hypothetical Inferential Theory: Inference and belief within conditionals
Creators: name: Elqayam, Shira
name: Douven, Igor
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Philosophy
subject: FOS: Philosophy, ethics and religion
subject: Arts and Humanities
subject: Philosophy of Mind
subject: Cognitive Psychology
subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology

description: Conditionals, sentences of the structure ‘If p, then q’, are the building blocks of discourse, logic, and thinking. Being able to consider “if… what then?” is essential for the human ability to think hypothetically of possibilities removed in space and time (Evans &amp; Over, 2004). We say “if” to make promises, threats, and decisions; to lay down the law; to express causal and probabilistic relations; to express regret on what might have been. It is small wonder, then, that conditionals have been at the heart of much research and debate, and that a comprehensive theory of conditionals has become a Holy Grail for psychologists and philosophers alike. In this project, we propose a novel way to test our new theory of conditionals, Hypothetical Inferential Theory (HIT) (Douven, Elqayam, Singmann, &amp; van Wijnbergen-Huitink (2018; henceforth DESV). Consider the following two conditionals: 1. If nurses are paid better, then recruitment of nurses will increase 2. If nurses are paid better, then the stocks of Apple will rise Conditional (1) is straightforward, but conditional (2) is much harder to make sense of. Recent research (Krzyżanowska, Wenmackers, &amp; Douven, 2014) traces the difference to an intuitive link between the “if” part of the sentence, and the “then” part (technically known as “antecedent” and “consequent” respectively), present for conditional (1) but not for conditional (2). Conditionals like (2) are now often referred to as missing link conditionals. HIT is combines insights from the philosophical theory of inferentialism (Krzyżanowska et al., 2014) and the psychological theory of hypothetical thinking (Evans, 2006, 2007). According to inferentialism, we understand conditionals by inferring from if to then. In the world we know, if nurses are paid better, it is reasonable to infer that their recruitment will increase; but it would be bizarre to infer from nurses’ salaries to Apple’s stocks in the market. Thus, we think that (1) is true, but (2) lacks a truth value (it just makes no sense). HIT augments this philosophical principle with the psychological idea that this inference from if to then need only be subjectively strong enough, as judged by the reasoner herself (Simon, 1983). In other words, HIT argues that conditionals are subjective mini-inferences. This approach is in contrast to competing theories, which regard conditionals as representing possibilities in the world (Johnson-Laird &amp; Byrne, 2002), or as probability relations between antecedent and consequent (Oaksford &amp; Chater, 2007). In support of HIT, we found that estimates of subjective inference strength from if to then predicted how often conditionals were evaluated as true; and that experimental test conditions designed to increase inference strength resulted in higher rates of conditionals considered true. There is a flip side: if people evaluate conditionals by testing the strength of the inference from if to then, these mini-inferences would be vulnerable to the same biases that are typical of human inference generally. And indeed, we found evidence that reasoners are biased by their belief in the consequent, in analogy to a well-documented effect known as belief bias (Evans, Barston &amp; Pollard, 1983); moreover, just like belief bias in syllogistic inference, belief interacted with the logic of the inferential relations. Paradoxically, biases provide powerful support for HIT: If it quacks like a duck, it’s a duck; if it behaves like an inference – biases and all – it’s an inference. This pioneering approach is informed by descriptivism (Elqayam &amp; Evans, 2011): we aim to study conditionals as they are, rather than as they ought to be. This project is funded by the Experimental Psychology Society Small Grant Scheme.