Reading Notes: August 5th, 2022

“Several writers including Paul Churchland and Gary Hatfield make the case that the argument for dualism commits the masked man fallacy; that the Cartesian argument relies on mere ignorance of the body to reach its conclusion. In this paper, I show that the argument from Cartesian doubt to mind-body dualism does not depend on mere ignorance. It depends on reliable knowledge about what can and cannot be known. Descartes’ method of doubt leads to the conclusion that the body can never under any circumstance be known as the mind is known. The argument for dualism rests on that knowledge, not on ignorance….Arnauld went on to say that Descartes’ distinction between mind and body is analogous to a person believing a right triangle to be something distinct from a figure which instantiates the Pythagorean ratio, merely because that person happens to not know that all right triangles do instantiate the Pythagorean ratio. The point of this objection is that merely knowing or doubting a thing does not count as a genuine property of the thing in question. How we happen to think about things, the knowledge we happen to lack, and the resulting certainty or doubt cannot in general be used to deduce the nature of things. Arnauld was pointing out what is usually called the intensional fallacy or the masked man fallacy…. Churchland went further than any other of Descartes’ critics by arguing against a potential objection to his accusation of fallacy. Because he did the most to defend the claim, I will primarily engage with Churchland in my argument against Descartes’ critics. (Doyle, Cartesian Dualism Does Not Commit the Masked Man Fallacy, 1-3) 

“Now I will refute the critique, using Churchland’s 1988 book, Matter and Consciousness as the main mark, with Hatfield as a collateral target. The wording of the Cartesian argument which I introduced above is from Churchland. It is the argument he sets out to knock down. For ease of reading, here it is again: “(1) My mental states are introspectively known by me as states of my conscious self. (2) My brain states are not introspectively known by me as states of my conscious self. Therefore, by Leibniz’ Law (that numerically identical things must have exactly the same properties), (3) My mental states are not identical with my brain states.” Churchland then gives what he sees as an analogous argument to show by example how the masked man fallacy works: “(1) Muhammad Ali is widely known as a heavyweight champion. (2) Cassius Clay is not widely known as a heavyweight champion. Therefore, by Leibniz’ Law, (3) Muhammad Ali is not identical with Cassius Clay.” This example of the masked man fallacy by Churchland shows that merely being thought of or recognized in one way or another is not a genuine property of a thing which actually distinguishes it from supposedly separate things. How people apprehend a thing can be wrong, incomplete, or change with time. One and the same thing might be recognized under one name, and yet fail to be recognized under another accurate name. Hatfield uses a very similar example meant to demonstrate the same point: “From the fact that the Joker cannot, at a certain moment, doubt the existence of Batman (because he is with him), but he can doubt the existence of Bruce Wayne (who might, for all the Joker knows, have been killed by the Joker’s henchmen), it does not follow that Bruce Wayne is not Batman. In fact, he is Batman. The Joker is merely ignorant of that fact.” The problem with both analogies is that they mischaracterize what is known and what is unknown. When considered more carefully, Descartes’ method of doubt does not merely lead to a lack of knowledge about the body; it leads to absolute certainty that the body will in principle never be known. The premise is not merely “I happen to lack knowledge of the body”; it is “The body is in principle uncertain from any and all perspectives.” The body is uncertain from the perspective of mind, and there are no alternative perspectives from which the body might be known. Any perspective from which knowledge of the body might be sought would be a subjectivity, a mind. There is no knowledge, certainty, or doubt that is not within a mind, and the body is uncertain to mind, so there is no certainty of the body from any logically possible perspective. In Hatfield’s analogy, “being with Batman” stands in for “certainty of the mind”, while “not being with Bruce Wayne” stands in for “uncertainty of the body”. To be truly analogous, the Joker should truthfully know that he in principle could absolutely never “be with” (be certain of) “Bruce Wayne” (that which stands in for the body). He would then rightly conclude that Batman (whom he is with) is not Bruce Wayne. To fully correct the analogy, the name “Bruce Wayne” should be replaced with a name that does not contradict the true conclusion. The Joker cannot, at a certain moment, doubt the existence of Batman (because he is with him), but he can doubt the existence of Frank Castle (whom he truthfully and for good reason knows can never be with him). It follows that Frank Castle is not Batman. This refutes Hatfield’s refutation of the argument for Cartesian dualism. But Churchland partially anticipated this response.” (Doyle, Cartesian Dualism Does Not Commit the Masked Man Fallacy, 4-5) [Underlining is mine]

“Churchland knew that someone like me might insist on premises like the following, which replace “known” with “knowable” in what I’ll call the updated argument: “(1’) My mental states are knowable by introspection. (2’) My brain states are not knowable by introspection. Therefore, by Leibniz’ Law, (3’) My mental states are not identical with my brain states.” Churchland readily admits that being knowable by introspection is a genuine property of a thing, and that the updated argument avoids the masked man fallacy. In order to counter this, he denies the updated premise (2’). As a proponent of physicalism, Churchland holds that mental states really are brain states. And if mental states actually are brain states, then it is really brain states that we introspect. In the case that physicalism is true, we all know brain states by introspection, but some of us just don’t know that we know brain states, much like the Joker could be with Bruce Wayne, but not know he is with Bruce Wayne. According to Churchland, premise (2’) is false and also begs the question. He again illustrates his critique by using a supposedly parallel argument: “(1) Temperature is knowable by feeling. (2) Mean molecular kinetic energy is not knowable by feeling. Therefore, by Leibniz’ Law, (3) Temperature is not identical with mean molecular kinetic energy.” Since we scientifically consider temperature and aggregate kinetic energy to be equivalent, premise (2) is false even though it does not seem obviously false to most people who are not thinking in terms of physical theories. Churchland says, and I agree, that, “Just as one can learn to feel that the summer air is about 70°F, or 21°C, so one can learn to feel that the mean KE of its molecules is about 6.2 x 10-21 joules, for whether we realize it or not, that is what our discriminatory mechanisms are keyed to.” But this temperature-energy example is not truly analogous to the updated mind-body argument. I’ll point out the difference and explain why premise (2’) of the updated argument is true and does not beg the question. The difference between the updated argument for dualism and Churchland’s temperature analogy is that we have from Descartes a very good reason to believe (2’), but there is no such reason to believe premise (2) of the analogy. Average molecular kinetic energy is something that might seem like it would not be knowable by feel, but no argument has been made as to why it can’t be known by feel. In contrast, there is an argument that tells us the body can never be known by introspection. That is Descartes’ persistent doubt. One can always doubt the existence of the body, since any visual or kinesthetic sensation could be an elaborate hallucination, dream, demonic influence, etc.” (Doyle, Cartesian Dualism Does Not Commit the Masked Man Fallacy, 5-6) [Underlining is mine]

“If we were to somehow scientifically learn that the mind is the body, we would only “know” that fact at the epistemic level where science takes place—where empirical measurements of the body are just assumed for practicality’s sake to not be elaborate hallucinations, dreams, or demonic influence. No matter what we learn about the body, nothing can bring that learning to the higher epistemic plane where it can’t be suspected of being some kind of dream. To put the same truth in another way, the body is uncertain from the perspective of mind, and there are no alternative perspectives from which the body might be known. Any perspective from which knowledge of the body might be sought would be a subjectivity, a mind. There is no knowledge, certainty, or doubt that is not within a mind, and the body is uncertain to mind, so there is no certainty of the body from any logically possible perspective. So premise (2*) is true. My brain states are not knowable by introspection. Obviously, the temperature analogy lacks any such justification for its premise (2). So it isn’t really analogous. Temperature and kinetic energy both begin and end in the empirical epistemic realm. Neither one is immune to doubt. By Cartesian standards, temperature and kinetic energy may be distinct, may be identical, or may not be properties of anything real at all. From the practical scientific perspective, temperature and kinetic energy are identical, though they were thought for some time to be distinct. But to work within the practical scientific perspective is to depart entirely from Descartes’ method of doubt, which is where premise (2*) of the updated argument for dualism comes from. Premise (2*) does not beg the question. It is itself the conclusion of a good argument. And (2*) would do a terrible job of begging the question, since it does not on its own imply that physicalism is false and mind-body dualism is true. Premise (1*) and Leibniz’ Law are also required in order to reach that conclusion. Since these other elements of the argument are required, it is clear that (2*) is just doing the work of an ordinary premise; it is not begging the question. Proving the truth of (2*) is the main Cartesian innovation. That innovation is not touched by any analogy such as Churchland’s, which does not prove the truth of its supposedly analogous premise in a comparable way. Premise (2*) does not beg the question, but if it did, that would be even worse for the physicalist, since (2*) is true. A true premise which begs the question would lead directly to the conclusion without even a need for the other elements of the argument. Since 2(*) is true, the updated argument for mind-body dualism is valid and sound, or at least it has not been shown to be otherwise.” (Doyle, Cartesian Dualism Does Not Commit the Masked Man Fallacy, 6-7) [Underlining is mine]