Infinitism, a theory of the structure of justification most recently developed and defended by Peter Klein, is the view that justification is a matter of having an infinite series of non-repeating reasons for a proposition. I argue that infinitism is preferable to foundationalism in that only infinitism can plausibly account for two important features of the structure of justification: 1) justification admits of degrees and 2) complete justification makes sense.

Meta-ethical non-cognitivism makes two claims—a negative one and a positive one. The negative claim is that moral utterances do not express beliefs which provide the truth-conditions for those utterances. The positive claim is that the primary function of such utterances is to express certain of the speaker's desire-like states of mind. Non-cognitivism is officially a theory about the meanings of moral words, but non-cognitivists also maintain that moral states of mind are themselves at least partially constituted by desire-like states to which moral utterances give voice. Non-cognitivists need a plausible account of what distinguishes whims, addictions and cravings from genuinely moral judgments. For while non-cognitivists maintain that in a suitably broad sense moral judgments just are constituted by desire-like states they also insist that not any old desire constitutes a genuinely moral judgment. Since the challenge is to demarcate what is distinctive about moral attitudes we might usefully call this the demarcation challenge.