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Steven M. Cahn

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In the argumentative dialectic between moral realists and non-cognitivist moral antirealists each side in the debate is typically thought to enjoy a different prima facie advantage over its rival. Moral realism gains plausibility from its truth-conditional semantics because it can explain the meaning of moral judgments on the same basis as ordinary propositions. However, many moral philosophers doubt moral realism because the theory is committed to the existence of moral properties, which are, in J. L. Mackie's term, "queer." Moral antirealism denies that these moral properties exist, and this is a principal reason why many moral philosophers endorse the theory. However, if moral terms like "good", "immoral", or "right" do not refer to anything, then the meanings of the moral judgments in which they appear cannot be explained with truth-conditional semantics; moral antirealists who wish to preserve moral practice need to develop a semantics that can accommodate it. The general perception of the dialectic is that moral realists have the upper hand in semantics, but a disadvantage in metaphysics, and vice versa for moral antirealists. This essay challenges this assumption.

Simon Blackburn's quasi-realism is one of the principal examples of non-cognitivism, a form of moral antirealism that tries to develop an alternative account of moral semantics in which the function of a moral proposition is not to express belief but attitude. Quasi-realism is Blackburn's research program of developing a semantics for moral discourse that is consistent with projectivism, the metaphysics of his metaethical theory. After situating Blackburn's project within the history of twentieth century metaethics, this essay reviews Blackburn's quasi-realist semantics and criticizes it. This essay then aims to extend the metaethical dialectic by developing and critiquing an account of Blackburn's projectivism.

This essay interprets projectivism as an explanation of moral awareness that aims to explain the realist phenomenology of that experience when realist explanations of it fail. After developing an account of the mechanism of projectivism, this essay argues that a metaethical theory feature projectivism as its metaphysical element contrasts negatively with moral realism in several ways: e.g., if it postulates new mental states and more events to account for moral awareness, then its ontological economy is less certain; it does not solve a metaphysical problem, supervenience, that moral realism cannot; it is incompatible with desirable features of moral practice; it undermines Blackburn's rejection of error theory. This essay then concludes that when assessing the dialectic between moral realism and non-cognitivist moral antirealism, it is inappropriate to presume a metaphysical advantage for the latter on the basis of the mere denial of the existence of moral properties. This suggests that non-cognitivist moral antirealists need to supplement their theories with more robust metaphysical research programs.

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