ABSTRACT
It is a pleasure to contribute to a volume honouring the work of Phil Johnson-Laird. My undergraduate thesis at the Center for Cognitive Science at Brown University was heavily based on Johnson-Laird’s then recently published book, Mental models (1983). Since then, Johnson-Laird has not only continued to be a mentor, but has become a cherished colleague and a dear friend. Ten years after my foray into the cognitive sciences, Johnson-Laird and I edited a volume dedicated to the interaction between research in reasoning and in decision making (Johnson-Laird & Shafir, 1993). Of particular interest were empirical findings and psychological principles that were shared by these two domains of inquiry, or that originated in one but could shed light on the other. It is on one such principle, the principle of compatibility, that I focus in what follows.
