This book puts forward an interpretation of rationality which is much broader than the one underlying the current polarity between analytic and continental philosophy. It will help to reaffirm a range of ideas which have long been pushed to the sidelines by the dominance of the geometric model of philosophical argument. Descartes's dream of attaining a 'certitude equal to the demonstrations of Arithmetic and Geometry' reinforced the assumption that rationality must be assessed in terms of logical structure. Against this, Pascal invoked the notion of 'finesse', and Warner extends Pascal's usage in this book to specify a related set of informal but legitimate styles of argument.