Substance Dualism is true

Thanks to n7 for his argument! I am trying to decide my stance on this issue, and I'm sure that this debate will help me in my decision. I can only hope that I will be able to pose a worth-while challenge to my esteemed opponent :) In this round, I will be putting forth my own arguments as well as rebutting my opponent's. ----------------------------------- The Case for Physicalism ----------------------------------- Simply put, there is no need for mind to exist apart from matter because neurological science already explains the vast majority of functions of the mind in materialistic, physical terms. It has become common knowledge among neuroscientists that emotions are a result of complex electrochemical reactions in the brain, with various neurotransmitters such as serotonin, dopamine, and oxytocin interacting with neurons in the frontal cortex [1]. Our sense of empathy, our ability to relate to other human beings, and many of our learned behaviors are now entirely attributed to mirror neurons in the brain, which, whenever we observe someone doing something, activate along the same exact neural pathways that they have active [2]. Theories of consciousness, too, have been gaining support in the scientific community; neurologists have discovered a certain area of the brain which appears to be responsible for weaving together the vast amounts of sensory and cognitive input we process into the "seamless web" of first-person experience which we perceive as consciousness [3]. These materialistic explanations of mind processes are given further credence by the fact that physical injuries and impediments to various portions of the brain result in the hindrance of those mind-processes. For example, scientists have discovered that autism is linked to structural problems in people's mirror neurons -- thus explaining autistic people's lack of empathy, inability to relate to other people, and difficulty with learning [2]. Another example: stroke victims tend to suffer permanent damage to certain parts of their brain due to the extended periods of time that they were deprived of oxygen, and one common effect of that is profound changes in personality and emotion [4]. This effect is also seen in patients with frontal lobe injuries, because it hosts so many of the electrochemical processes which are responsible for emotion [5]. The point of all this is that, if functions of the mind were really the responsibility of a wholly separate metaphysical entity, then we wouldn't expect these changes to the physical brain to result in such large changes to those mind-functions. In conclusion, the only metaphysical substance which we have ever had any experience with is that of matter, so we need positive reasons to believe that a completely different metaphysical substance also exists. However, all empirical investigation into the workings of the mind reveals that it is entirely a product of physical processes within the brain. Therefore, we have no rational basis for the belief that mind exists as an independent entity, and so substance dualism is false. -------------------------------- Problem of Interaction -------------------------------- Substance dualism is self-refuting. It would be plainly absurd to suggest that the physical brain has no part to play at all in the functions of the mind (as that would basically negate the entire field of neurology), so dualism forces us to assume that mind and matter somehow interact in order to produce the the processes of the mind as we know them. But how is it possible for two substances of fundamentally different metaphysical natures to interact? It is not possible for the mind to have physical properties, and it is not possible for matter to have mental properties. It is akin to trying to get alkaline metals to react with noble gases -- except mind-matter interaction is even more improbable because it has to surmount ontological differences, which are so fundamental that they make mere chemical differences seem rather superficial. In other words, substance dualism requires something which is impossible according its own claims, thus making it self-refuting. ------------------------------- Philosophical Zombies ------------------------------- (1) If P-zombies are possible, then the mind isn"t physical. (2) P-zombies are possible (3) The mind isn"t physical. C. Substance Dualism is probable. The only premise I can object to is the first one, and to be honest, I do not really understand Pro's justification of P1 at all, as it seems to be an enormous non-sequitur. He talks about the laws of identity, makes an appeal to authority, and then goes on to explain why kripkean modal logic is sound. Aside from the appeal to authority, the only time he says anything of relevance to the premise at hand is when he attempts to link the laws of identity to dualism: "If x= the mind and y= the physical we can understand why the first premise is true." Pro is going to need to elucidate more clearly why this is the case, because at present it is nothing but a bare assertion. Meanwhile, the only other thing I can address is the appeal to authority regarding the majority of philosophers agreeing with P1. Contrary to Pro's claims, that is *not* a valid appeal. If appealing to expert consensus like that could determine truth, then Geocentrism would have been true in 700 years ago but false today. Logical Positivism would have been true in the 19th century but false in the 21st. Young Earth Creationism would have been true before Darwin was born but false after he died. Of course, all of those are absurd, because such propositions about reality are meant to be objective -- not dependent upon what the majority of experts believe at the time. If expert consensus determined truth value, then new scientific theories would automatically be false because they invariably conflict with what the majority of the field already believes. It is simply not tenable to assume things based on appeals to authority like the one Pro has put forth. Pro's only real support for his first premise fails, and thus the conclusion remains unwarranted. ----------------------------- Knowledge Argument ----------------------------- (1) Mary has all the physical information concerning human color vision before her release. (2) But there is some information about human color vision that she does not have before her release. (3) Therefore, not all information is physical information. The problem with this argument is that premise 1 is plainly false. By learning all there is to know about the physics of color, Mary did *not* actually have all the physical information concerning human color vision. She only had mechanical, third-person information on what color is; she did not have *sensory* information about human color vision -- which is inherently first-person -- hence why she felt that she was learning for the first time "what color actually is". Since sensory information is a category of physical information, and Mary did not have sensory information of human color vision, the first premise is false and Pro's syllogism is unsound. . . . == Conclusion == I have put forth two arguments showing that physicalism accounts for the mind far better than substance dualism does: (1) the explanatory power of modern neuroscience, and (2) the self-refuting nature of substance dualism. Meanwhile, neither of Pro's arguments for dualism hold up to scrutiny. The resolution is negated. Back to you, Pro! . [1] http://www.neuroanatomy.wisc.edu... [2] http://greatergood.berkeley.edu... [3] http://www.livescience.com... [4] http://www.strokeassociation.org... [5] http://www.neuroskills.com...