cal to, descriptive properties, and furthermore are not themselves scien-tific properties (65-66). Why nonreductive versus reductive moral realism? One of Shafer-Landau’s main reasons is inductive, namely, that we cannot overlook the “signal failure of classical naturalists to plausibly defend any robust iden-tity claims linking the fundamental moral properties with natural ones” (67). And why nonreductive nonnaturalismrather than nonreductive naturalism? Here one important consideration seems to be that for Shafer-Landau, moral obligations are intrinsically reason-giving, which is something that descriptive properties are not (112). And another con-sideration is that moral standards “function as devices for specifying oughts. And that is not something that neatly fits the paradigm of de-scriptive, scientific laws” (112, emphasis his). Much of Shafer-Landau’s attention in this part of the book is devoted to responding to three important arguments against nonnaturalism—Blackburn’s well-known supervenience argument, an argument to the effect that nonnaturalists cannot explain why certain particular descrip-tive properties constitute a given moral property as opposed to some other descriptive properties, and a family of arguments alleging that moral properties are explanatorily inefficacious. Let me pursue the last line of discussion in more detail. Shafer-Landau provides the following formulation of what he takes to be the strongest challenge to moral realism from considerations of ex-planatory adequacy: (1) Moral facts do not cause anything in the non-moral realm. (2) Moral facts do not cause anything in the moral realm. (3) Therefore moral facts do not cause anything at all. (4) If a putative fact causes nothing, then we lack any reason for justifiedly believing that it exists. (5) Therefore we lack any reason for justifiedly believing that moral facts exist. (105)66Shafer-Landau provides two additional premises in order for the overall conclusion to be that we have good reason to denythe existence of moral facts, but for the sake of
6 Christian Miller While there might be good reason to question (4), Shafer-Landau’s pri-mary response is, as far as I can tell, to reject (1). What makes his discus-sion here novel and interesting in my view is that he rejects (1) by con-sidering Kim’s well-known argument against nonreductive physicalism in the philosophy of mind.7Here is Shafer-Landau’s formulation of Kim’s argument: (A) The physical domain is causally closed—every physical event has a full and complete set of physical antecedents that cause and explain its occurrence. (B) The mental is not identical to the physical. (C) Therefore if mental facts cause physical occurrences, then there is systematic causal overdetermination of physical occurrences. (D) There is not systematic causal overdetermination of physical occurrences.