And how on earth is it to be decided which of the two things it is rational to be most certain of?
G. E. Moore, Four Forms of Scepticism (emphasis his)
G. E. MOORE'S LEGACY TO MORAL philosophy has been both profound and controversial. Most notably, his Principia Ethica is often treated as a crucial starting point for work in what is now typically called "metaethics," and metaethicists have returned again and again to defend, debunk or diagnose the appeal of his Open Question argument. This paper examines the implications for moral philosophy of one of Moore's other famous (or, depending upon your tastes, infamous) forms of argument: the table-turning maneuver that he deployed against the epistemological skeptic and the metaphysical idealist.
Against such revisionary metaphysical and epistemological views, Moore claimed that the following constitutes a proof of the existence of his hands, and thereby of the external world:
I can prove now, for instance, that two human hands exist. How? By
holding up my two hands and saying, as I make a gesture with the
right hand, "Here is one hand," and adding as I make a certain
gesture with the left, "and here is another." (1959, 145-6)
The (implicit) remainder of the proof can be represented as follows:
HANDS 1. If the external world did not exist, then I would not have hands.
2. I have hands.
3. The external world exists. (1)
Just as some global skeptics and idealists purport to diagnose and correct deep errors in common-sense thinking about the external world, many philosophers have challenged what they take to be common sense about morality. (2) A particularly radical form of revisionism is metaethical error theory. As I am thinking of it, metaethical error theory consists of two claims. First, error theorists are descriptivists in moral semantics: they claim that in our standard use of moral language, we purport to predicate moral properties such as goodness or wrongness of acts, agents, etc. Second, they are nihilists about moral metaphysics: they claim that nothing has such moral properties. (3)
Someone favorably disposed toward Moore's response to the skeptic and the idealist might be tempted by an analogous response to revisionist views in ethics. Such a response is exemplified by the following argument against error theory:
NO ERROR 1. If metaethical error theory were true, then torturing innocent children just for fun would not be wrong.
2. Torturing innocent children just for fun is wrong. (4)
3. Metaethical error theory is false.
Some recent discussions of metaethical error theory and nihilism can be interpreted as appealing in part to the sort of argument offered in NO ERROR. (5) The structural similarity between NO ERROR and HANDS can be illuminated by thinking of them as instances of a simple schema. Where a putatively revisionary thesis (R) conflicts with a common-sensical Moorean premise (M), we can represent the form of these arguments as follows:
SCHEMA 1. If R then not-M
I will call instances of this schema Moorean arguments. One might take this shared schematic structure to suggest that Moorean arguments in ethics stand or fall with canonical Moorean arguments like HANDS. (6) In this paper, I argue that this is not so.
Much of the recent literature on Moorean arguments has focused on evaluating an important cluster of related objections to the use of Moorean arguments. For example, it has been argued that Moorean arguments beg the question, or that they fail to transmit justification from their premises to their conclusions. (7) Insofar as they have force, such worries typically afflict arguments with the Moorean structure quite generally. The issues raised by these objections are highly complex, and I will not address them in this paper. …