Abstract

This chapter shows how the main principle points the way to a solution to the two deepest mysteries in moral philosophy, one metaphysical and one epistemological. The metaphysical mystery is to explain why moral norms and principles always seem to have exceptions. The epistemological mystery is to explain how human beings could come to recognize exceptions to the very moral norms and principles that were used in their moral training. The solution to the metaphysical mystery is to see that moral reasoning has a reference class logic, modeled by conditional probability. The solution to the epistemological mystery is to see that moral training can produce practical wisdom, understood as implicit sensitivity to the main principle. The chapter also reviews the historical discovery of the paradox of direct consequentialism to explain why the main principle does not endorse a change to using it as a ground-level moral principle. The chapter then compares the book's account of legal improvement with R. Dworkin’s account of law as integrity on the issue of retroactivity in the civil law.