This book, based on Grice's 1979 Locke Lectures at Oxford and published posthumously, elaborates the notions of reasons, reasoning, and rationality, with particular emphasis on the unity of practical and non‐practical (‘alethic’) reasoning. It begins with a look at the nature of ordinary reasoning and distinguishes between ‘flat rationality’, the formal capacity to apply inferential rules, and ‘variable rationality’, the excellence or competence of good reasoning (Ch. 1). Grice then proposes an ‘Equivocality Thesis’, arguing that a structural representation can be given for justificatory (norm ... More

This book, based on Grice's 1979 Locke Lectures at Oxford and published posthumously, elaborates the notions of reasons, reasoning, and rationality, with particular emphasis on the unity of practical and non‐practical (‘alethic’) reasoning. It begins with a look at the nature of ordinary reasoning and distinguishes between ‘flat rationality’, the formal capacity to apply inferential rules, and ‘variable rationality’, the excellence or competence of good reasoning (Ch. 1). Grice then proposes an ‘Equivocality Thesis’, arguing that a structural representation can be given for justificatory (normative) reasons that allows for modals (ought, must, etc.) to be used univocally across the alethic/practical divide in terms of general acceptability statements (Chs. 2–3). In addition, he shows that valid inferences can be drawn from alethic to practical acceptability statements (Ch. 4). Finally, Grice provides a characterization of happiness as it features in practical thinking, and suggests it to be an ‘inclusive end’, consisting of the realization of other ends that are desirable for their own sake as well as for the sake of happiness (Ch. 5). An extensive introduction by Richard Warner provides a helpful summary and explanation of key aspects of the book.