A Reply to Shafer-Landau

**This is from guest blogger, Aaron F.**

In, “Ethics as Philosophy: A Defense of Ethical Nonnaturalism” (Ethical Theory: An Anthology 62-71), Russ Shafer-Landau defends ethical nonnaturalism. His first step is to convince us of moral realism which he defines with a set of three theses. They are, “(i) moral judgments are beliefs that are meant to describe the way things really are; (ii) some of these beliefs are true, and (iii) moral judgments are made true in some way other than by virtue of the attitudes taken towards their content by any actual or idealized human agent” (62). Thus, moral realism as defined here is incompatible with emotivism, subjectivism, and error theory. It may not be immediately clear that error theory is ruled out (it was not to me) since one might think that a statement such as, “there are no true moral statements,” is a negative moral principle. However, since moral principles must be about what is right or wrong, good or bad, etc., and the thesis of error theory is about what is true (or, in this case, false), the claim that there are no moral truths is not itself a moral statement. With his in place, he presents the following argument.

 1. Ethics is a species of inquiry; philosophy is its genus.
 2. A species inherits the essential traits of its genus.
 3. One essential trait of philosophy is the realistic status of its truths.
 4. Therefore, moral realism is true. (62)

The first two premises are taken for granted (it is difficult to see how they could be false), and Shafer-Landau argues for the third with the remainder of the article. However, I believe that the argument is not complete. In particular, it does not follow from the premises that error theory is false. This also means, of course, that the premises do not entail the conclusion.
 

Error theory is true just in case all moral judgments are false, and all moral judgments would be false if there were no basic ethical principles. Let us see if we can make error theory consistent with premises one to three. We are told by premise one and premise three that philosophy is a genus of inquiry whose truths have realistic status. I find that the most natural way to interpret this is to think of philosophy as a discipline whose
aim is to discover the elements of a set P of philosophical truths and principles. Then, species of philosophy attempt to discover the content of subsets of P.

But it is the case that every set has the empty set as a subset. Hence, it is possible that the subset E of ethical
truths and principles is empty. If this is so, then all ethical statements will be false because there will be no principles according to which anything can be judged to be good or bad, right or wrong, etc. As for consistency, that E be empty clearly does not conflict with premise two. Premise one simply says that E is contained in P,which is true if E is the empty set, and premise three only mentions the status of elements of P. Hence, it does not follow that E is not empty, which means that the conclusion of the argument is not entailed by its premises.

The solution to this problem is obvious. Simply add two premises: first, “‘such-and-such’ is a true ethical principle,” and second,“therefore the set of ethical truths and principles is not empty.” Given these premises, and the ones in the original argument, it would follow that moral realism is true. However, we are now required to have at least one true moral principle. Moreover, it seems that we must have at least one realistic moral principle (in the sense of moral realism), for if it were, for instance, a subjective moral principle, premise three of the original argument would disqualify it as a potential element of E.  On the other hand, one might solve the problem by presenting a non-set theoretic interpretation of the relationship between philosophy and ethics. However, I do not know what such an interpretation would be.