Thinking about the Liar, Fast and Slow

The liar paradox is widely conceived as a problem for logic and semantics. On the basis of empirical studies presented here, we suggest that there is an underappreciated psychological dimension to the liar paradox and related problems, conceived as a problem for human thinkers. Specific findings suggest that how one interprets the liar sentence and similar paradoxes can vary in relation to one’s capacity for logical and reflective thought, acceptance of certain logical principles, and degree of philosophical training, but also as a function of factors such as religious belief, gender, and whether the problem is treated as theoretical or practical. Though preliminary, these findings suggest that one reason the liar paradox resists a final resolution is that it engages both aspects described by so-called dual process accounts of human cognition.