Valerie Hardcastle:
Let us pretend that my version of Einstein is correct for the sake of this dicussion. Einstein proposed a theory that was well-grounded in reasoning, but for which there were no confirming experiments available at the time (for lack of technology). So the theory was unproven, true, but I would say that it was also nonnaturalistic because there *wasn't* an experiment that could be done at the time to corroborate or refute Einstein's hypotheses.
Although Einstein may have relied on thought experiments rather than empirical findings in developing the theories of special and general relativity, the theories did make predictions that were testable and tested at the time. Astronomers already knew about the precession of the perihelion of the orbit of Mercury before Einstein developed the General theory of Relativity, they just didn't have a satisfactory explanation for it. The General theory provided one. Einstein's General theory also predicted that the sun's gravitational field would bend starlight by a specified amount, and this prediction was tested within just a few years thereafter (by observing stars near the sun's disk during a total solar eclipse) and found to be correct.
Hardcastle continued:
So, Sutherland is right when he says that a theory must be open to empirical testing to be naturalistic. I also claim (and here I think he disagrees with me) that "open to empirical testing" means "open to empirical testing using the tools we currently have available;" that is, we can see how the test should go.
Okay, back to Chalmers. What sort of test are we supposed to run to test his hypothesis? Beats me. So far as I know, there aren't any experiments, given the tools we have available today, that would shed light on his proposal. Hence, I claim his theory is nonnatural.
This is quite different from the definition of naturalism that I've encountered elsewhere. Naturalism, by this definition, is the metaphysical assumption that all natural phenomena can be explained in terms of natural (as opposed to supernatural) causes. A theory would thus be naturalistic so long as it does not invoke supernatural entities (ie. God, angels, demons, ghosts, or immaterial souls) By this definition Einstein's special and general theories of relativity would clearly qualify as naturalistic. Since Chalmers is a property dualist, and does not postulate the existance of an immaterial substance or soul, his views would also qualify as naturalistic in this sense. I don't see any way that excluding the supernatural necessarily entails the exclusion of assumptions that aren't experimentally testable. Hardcastle apparently wants to add testability to the list of criteria for naturalism, for the main purpose of labeling Chalmers ideas as "non-natural". It seems to me that what Chalmers is trying to do is to develop a metaphysical framework within which scientific hypotheses can be formulated and tested. He is not himself trying to develop a testable scientific hypothesis. Materialism is also a set of metaphysical assumptions within which testable scientific hypotheses can be formulated. How would one go about experimentally testing materialism itself (as opposed to a specific scientific hypothesis expoused by materialists?). If Chalmers property dualism is "non-natural" because it isn't experimentally testable, then aren't materialists in the same boat?
Paul Patton
Mercer University School of Medicine
Metaphysics isn't science, true. So the metaphysical positions of materialism or dualism fall outside the scope of natural/natural distinction. However, once one choses a framework, and proposes specific ways of understanding the world within that framework (i.e., creates theories), then we can ask whether those are natural or not (regardless of framework). Chalmers does more than simply say he is a dualist; he proposes a specific way of working out his dualism. Unfortunately, his way of working it out (as this will be true for all versions of dualism I am familiar with) is not testable. Hence, I claim his theory is nonnatural.
