Abstract

This dissertation is a study of the nature of moral reasons and of how it is that moral reasons can be used to justify actions. I consider several theories and reject them in favor of moral constructivism. ;Chapter One rejects Williams' view that there must be an 'internal' connection between an agents' justifying reasons, and that agent's present motives. Williams thinks this requirement follows from the fact that reasons can be used to explain as well as to justify actions. I argue for the constructivist thesis that the justifying role of reasons depends on claims about considerations which a reasonable and rational person would accept, even when these considerations cannot explain what we do . ;Chapter Two defends this thesis against Hume's more radical rejection of the possibility and distinctive role of justifying reasons. The argument against Hume gains support for its claims about the nature and importance of reasonable and rational judgment in moral thought from 17th century rational intuitionism. ;Chapter Three argues that our rational commitments provide an important basis from which moral principles can be constructed. This is true even if the reasons which stem from our commitments do not hold universally. Constructivism can accommodate legitimate variation in the content of justifying reasons. ;Chapter Four examines the nature of the constructivist's reasonable requirements on the hypothetical point of view used to construct moral justifications. I rely on Scanlon's contractualism, which exemplifies important features of a constructivist approach. To highlight these features, I compare and contrast contractualism with Habermas's discourse ethics. ;Chapter Five argues against Walzer's theory of justice as social meanings. While it is true that the content of principles of justice is importantly shaped by social meanings, they do not limit the possible set of moral reasons for members of a society. Constructivism enables us to formulate minimal standards of decency based upon reasons which could be 'external' to a society's accepted social forms. ;I conclude that of the views surveyed in this dissertation, constructivism best solves the problems posed to it, and offers the most convincing account of the nature of justifying reasons