Abstract: Chapters 8–10 discuss the measurement of individual perfections, especially the theoretical and practical perfection that realize theoretical and practical rationality. This chapter introduces the basic structure of this measurement, which looks both to the number of certain states a person has – beliefs for theoretical perfection, intentions for practical perfection – and their score on a dimension of quality. It then elaborates on the dimension of number by discussing the further conditions a state must meet to count for perfection. Are all beliefs of a person relevant, or only those that are true, justified, or both? Do all the ends he intends count, or only those he achieves, is justified in believing he will achieve, or both? Discussion of these alternatives raises issues about romanticism, prudence, relations between the mind and world, and more.

Keywords: belief, intention, justification, measurement, practical rationality, rationality, romanticism, success, theoretical rationality, truth, value,