 The second stage: What principles must a free adopter and pursuer of ends embrace in order to qualify as rational? Grice addresses this question most fully in Aspects of Reason and The Conception of Value. The idea is that the combined requirements of rationality (outside ethics), freedom, and happiness impose substantive constraints on all persons. Grice develops this theme with great insight and subtlety; however, he did not complete the project, and the intricacies of his views are best left to the detail of his own works.