In this book Foley offers a major new theory of rationality. His aim is to escape the `doldrums of Descartes' by lowering the standard for what is rational from his impossibly demanding level of certainty. Foley takes a belief's being rational as a matter of its seeming from some perspective to be objectively likely to be true. This makes for an attractive mix of subjective and objective components in his concept of rationality. The subjective component makes rationality attainable; the objective component preserves the discipline of external constraint.