Substance Dualism or Eliminativism

Physicalism (P) entails minimal physicalism (MP), MP entails minimal supervenience (MS), and MS is the thesis that there is covariance between the supervenient and the subvenient stuff. Therefore, if the (alleged) supervenient and subvenient stuff do not covary, then MS is false, and if MS is false then MP is false, and if MP is false then P is false. Put differently: if MS is false then P is false—P stands and falls with MS. In this essay, I begin by showing what the minimal physicalist thesis is: MP is, essentially, MS. Next, I look at qualia and the trouble they pose to MS and hence MP: if it is possible that qualia can be inverted without a behavioral change, then it follows that MS, MP, and P are false. In other words, the possibility of inverted qualia show that P is false. Seeing that this possibility does not establish a very robust dualism, I turn to the issue of inverted selves: if inverted selves are possible, then full-blown substance dualism follows. I argue that inverted selves are possible. 1. Minimal Physicalism Minimal physicalism (MP) is the thesis that one is minimally committed to if one is a physicalist. This is not to say that this is the only thesis a physicalist holds, but if one is a physicalist, then one affirms MP. So a physicalist affirms MP plus other theses. This entails that if MP falls, then so does physicalism. Put differently: if MP is false, then physicalism (P) in all its forms is false. The converse, however, does not hold true: if P is shown to be false, it does not follow that MP is false, for MP does not entail commitment to P. For current purposes, it does not matter what we take P to be— perhaps P is the identity thesis or eliminative materialism—whatever it is, that is not relevant. So what is MP? Jaegwon Kim says that “[m]ind-body supervenience can usefully be thought of as defining minimal physicalism—that is, it is a shared minimum commitment of all positions that are properly called physicalist.” So MP is the thesis 1 13, Physicalism, Or Something Near Enough. Princeton: Princeton University Press, 2007. Res Cogitans (2016) 7 Hendricks | 13 2155-4838 | commons.pacificu.edu/rescogitans that the mind (i.e. mental states) supervenes on the body (i.e. physical states). But what is supervenience? Kim suggests that “covariance is the crucial component [of supervenience]; any supervenience concept must include this condition in some form” and covariance, Kim says, is the thesis that “[s]upervenient properties covary with their subvenient, or base, properties. In particular, indiscernibility in respect of the base properties entails indiscernibility in respect of the supervenient properties.” In other words, the minimal supervenience (MS) thesis is that the supervenient and subvenient properties (or stuff) covary: there is no difference in one kind without a difference in the other kind. We are now in position to define MP: MP necessarily entails MS, and MS is the thesis that the supervenient and the subvenient stuff covary. Thus, all that is needed to show that MP—and hence P—is false, is that it is possible that there be a change in one kind of stuff without there being a change in the other kind.