- From Thick to Thin: Two Moral Reduction Plans1
Many philosophers of the last century thought all moral judgments can be expressed using a few basic concepts — what are today called ‘thin’ moral concepts such as ‘good,’ ‘bad,’ ‘right,’ and ‘wrong.’ This was the view, first, of the non-naturalists whose work dominated the early part of the century, including Henry Sidgwick, G.E. Moore, W.D. Ross, and C.D. Broad. Some of them recognized only one basic concept, usually either ‘ought’ or ‘good’; others thought there were two. But they all assumed that other moral concepts, including such ‘thick’ ones as the virtue-concepts ‘courageous’ and ‘kindly,’ can be reductively analyzed using one or more thin concepts and some more or less determinate [End Page 515] descriptive content. This was also the view of many non-cognitivists who wrote later in the century, including C.L. Stevenson and R.M. Hare. They thought judgments using thin terms express one or two basic moral attitudes, either pro or con and with distinctive formal features such as categoricity and universality, and that any thick terms can be reduced to thin ones plus some description.
In recent decades a contrary view has emerged that claims that thick concepts are irreducible. According to its proponents, terms like ‘courageous’ and ‘kindly’ have both morally evaluative and descriptive meaning, but the two interpenetrate each other in a way that makes the separation a reductive analysis requires impossible. Thick concepts are therefore not derivative from thin ones, which do not have the primacy the above-mentioned philosophers assumed. On the contrary, on some versions of this anti-reductive view it is the thick concepts that are primary, with the thin ones mere abstractions from them.2
The mark of a thin concept like ‘right’ is that it says nothing about what other properties an item falling under it has. If moral properties supervene on non-moral ones, as most philosophers accept, then any act that is right will have other, non-moral properties that make it right. In addition, if moral judgments are universalizable, as the non-naturalists and non-cognitivists believed, then any other act with the same non-moral properties will likewise be right. But while the claim ‘x is right’ says or implies that x has some right-making properties, it says nothing about what in particular they are. If we know the other evaluations that someone who asserts this claim has made, we may be able to guess what right-making properties he has in mind now; if we know the general evaluative practices of his culture, that knowledge may also help. But these speculations go beyond the semantic content of ‘x is right’ itself, which says only that some properties of x make it right without specifying what they are. The reductive view therefore analyzes ‘x is courageous’ into an evaluative component that does not say anything about x’s non-moral properties and a descriptive component that does. The anti-reductive view says this separation is impossible.
In this paper we will defend the reductive view of thick concepts by answering the most common argument against it, and in so doing will defend a position held by more philosophers than the recent literature suggests. This literature has tended to associate the issue about thick concepts with that between cognitivist and non-cognitivist accounts of moral judgment, as if the reductive view were essentially non-cognitivist [End Page 516] and therefore one all cognitivists must deny.3 Now, it is indeed essential to any non-cognitivist view to separate evaluation sharply from description and so to require some reduction of thick concepts; an attack on reductivism is therefore also an attack on non-cognitivism. But the historical record shows cognitivists like Sidgwick and Moore just as much as non-cognitivists like Stevenson taking the reductive line. Nor do we see the slightest inconsistency in combining the cognitivist view that moral judgments express beliefs with the reductive view that they all use a few thin concepts. So while non-cognitivism is committed to some version of the reductive view, cognitivism can either accept...