Moral judgements have a dyadic nature. Normally we experience some pressure to act in line with our moral judgements, even if it’s regularly overcome by fear, selfishness, laziness, or other forces. This is evidence that moral judgements are desire-like, as expressivists contend. On the other hand, moral judgements also have the features of beliefs. They can be true or false, as cognitivists maintain, and justified and reasoned about in the way other beliefs are. Rather than deny one of these two aspects, this thesis is ultimately a defence of higher-order expressivism according to which moral judgements are hybrid mental states composed of beliefs and desires. However, only two of the chapters (2 and 3) contain arguments in favour of this specific kind of expressivism. The first chapter – What is Expressivism? – argues for a general characterisation that will be useful for friends and foes alike, and the final two chapters address problems that are common to all expressivists.
After we find out what expressivism is, I turn to the problems with pure versions according to which moral judgements are only desire-like states. I argue in chapter 2, The Problem with Purity, that pure expressivists are unlikely to be able to solve the Frege-Geach problem but higher-order (and other hybrid) expressivists can. In chapter 3, Metaphysics for Expressivists, I make a case for the inescapability of metaphysics even on the expressivist picture, which puts more pressure on pure versions of expressivism. I then show why higher-order expressivists must think moral properties are reducible to bog-standard descriptive ones. I end by arguing that this expressivist take on moral naturalism is better than cognitivist versions of naturalism.
Chapter 4 is about how to understand moral disagreement. If moral judgements are desire-like, why does it make sense to say that two people morally disagree? I propose An Assertoric Theory of Disagreement whereby people express disagreement by asserting inconsistent things (and the problem of inconsistency is addressed in chapter 2). Finally, chapter 5, Error and the Limits of Quasi-Realism, is about how to understand the thought that our moral beliefs might be mistaken. I defend the standard expressivist construal of it being a case of thinking we might change our minds after we’ve gathered more evidence, cohered our beliefs and generally improved our epistemic situation. I then argue this yields a transcendental argument against scepticism: it tells us that it is incoherent to believe we might be utterly unable to access the moral truth. The upshot is that expressivists cannot “mimic” realism completely, but if this simply means that our door is closed to radical scepticism whereas theirs is open, this is all the better for expressivism.
