Knights, Knaves, and the Ramsey Test: The Effect of Embedded, Indeterminate, and Paradoxical Antecedents

SPEAKER

Shira Elqayam

ABSTRACT

The suppositional theory of conditionals, both in its philosophical and psychological versions, adopts the Ramsey test as a general principle underlying conditional thought: hypothetically assume the antecedent, then evaluate the consequent in that context. However, in some cases, hypothetically assuming the antecedent is psychologically tricky. The prototypical case is a conditional with a paradoxical antecedent. For example, participants find sentences such as ‘If I am a liar then I enjoy listening to Michael Jackson’, with the Liar paradox in the antecedent, difficult to evaluate. In contrast, a Truth-teller antecedent (‘If I am a truth-teller, then I read a broadsheet newspaper’) is simply assumed to be true, resulting in a ‘collapse illusion’ (Elqayam, 2006; Elqayam et al., 2008). Hypothetical thinking can be compared with Chomskyan centre-branching syntax: In both cases, embedding is subject to severe processing constraints, since iterated embeddings rapidly become computationally intractable. Empirical evidence for the collapse illusion and the iteration thesis is presented, and the findings discussed within a general framework of hypothetical thinking theory.