The mental model theory of free choice permissions and paradoxical disjunctive inferences
P. N. Johnson‐Laird, Ana Cristina Quelhas, Célia Rasga
Abstract
Inferences of the sort: A or B; therefore A, are invalid. Yet, the paradoxes of free choice are acceptable: You can have sole or lobster; so, you can have sole. Pragmatic theories attempt to save logic. A semantic theory of human reasoning is founded on mental models of possibilities. “Or” refers to a conjunction of possibilities that each hold in default of knowledge to the contrary. A disjunction: it is permissible to do A or to do B, yields a deontic interpretation of the possibilities, and elicits mental models of a conjunction of default permissions. They yield or-deletions, such as: therefore, it’s permissible to do A. The theory predicts the paradoxes and new phenomena, which four experiments corroborated. For example, exclusive disjunctions such as: Few of the artists are brutalists or else cubists, have an intuitive model that yields or-deletions, but deliberation can construct models that refute them.