--- - |2 Mercier and Sperber illuminate many aspects of reasoning and rationality, providing refreshing and thoughtful analysis and elegant and well‐researched illustrations. They make a good case that reasoning should be viewed as a type of intuition, rather than a separate cognitive process or system. Yet questions remain. In what sense, if any, is reasoning a “module?” What is the link between rationality within an individual and rationality defined through the interaction between individuals? Formal theories of rationality, from logic, probability theory and game theory, while not the focus of Mercier and Sperber's book, may help clarify this latter question. - Mind & Language, EarlyView.