That the mind is a purely physical substance.

I do appreciate lucidity in an opponent, so thanks to 113086 for that opening.In this round, I will only be responding to Pro's opening. I will use my conclusion to respond to his rebuttal of my opening.I. The argument from causal closure.Pro begins with the axiom that every caused event has a physical cause. He goes on to say that mental events cause physical events. It would follow from the axiom and this first premise that mental events are physical causes. He explains in his second premise how that is possible, namely by mental events supervening on physical events.I completely agree with him that mental events cause physical events, which negates epiphenomenalism (epiphenomenalism is the view that physical events cause mental events, but the direction of causation does not go the other way around). However, I think his axiom begs the question against substance dualism. If substance dualism is true, then it would not be the case that every caused event has a physical cause. So Pro cannot use his axiom as a starting point lest his argument be circular.There are a number of problems with the view that mental events are supervenient properties of physical events.a. in every other case of a supervenient property, the property is open to third person observation. For example, when hydrogen and oxygen come together to form water, wetness emerges as a supervenient property, and it is open to third person observation. But mental properties are not open to third person observation. A scientist could give an exhaustive physical description of the brain and never make reference to mental events. Mental properties are just not physical properties.b. If supervenient mental events cause physical events, they only do so by virtue of their syntax (i.e. their underlying physical structure) rather than their semantics (i.e. their meaning or propositional content). Mental events, such as beliefs and desires, have intentionality. That is, they are about things, and directed toward things. If the semantical content of our mental states are irrelevant to behavior, then we should not expect there to be a correlation between our intentions and our behavior. Moreover, we should not expect evolution to have produced reliable belief-producing cognitive faculties.c. It is hard to see how the supervenient view escapes the problems of epiphenomenalism. It seems to me that epiphenomenalism would follow from the supervenient view. Each brain state from moment to moment is in strict causal relation with the previous brain state, and there doesn't seem to be any room for mental agents to act. Supervenient properties just ride on top of the physical events. The sense we have of acting intentionally would just be an illusion.d. If the supervenient view is correct, then there is no enduring self from moment to moment. The self is just a series of mental events which are properties of physical events. There is no self that has the mental events. The mental events are just had by the brain. Since the mental events are in a constant state of change, there is no enduring self.e. A good scientific theory is able to make accurate predictions. A chemist can predict the properties of water by knowing the properties of hydrogen and oxygen. But in spite of the wealth of knowledge we have about brains, there is nothing from which to predict mental phenomenon. We currently have no theory whatsoever that predicts minds, nor any idea how such a theory could be conceived. The fact of the matter is that there is nothing about the physical structure of the brain or any other entity that would give us any reason to expect mental events to emerge as properties.II. The argument from methodological naturalism.I agree with Pro's axiom that it is rational to base our metaphysical beliefs on the methods of science as long as this axiom does not mean that the methods of science are the only means by which we can arrive at rational metaphysical beliefs, and as long as it does not mean all of our metaphysical beliefs should be based on the methods of science. If the axiom merely means that scientific methods can give us true information about the world, then I wholeheartedly agree with it.I disagree with his premise that the methods of science lead to a physicalist system. They don't. The methods of science can only tell us how the physical world operates when there are no non-physical interventions. Granted, if there were continuous non-physical interventions, then scientific methods could tell us little about the laws of nature. But interventions need not be continuous to be actual. In fact, they may be quite rare as in the case of miracles which no description of nature could predict. If they are rare, then we should expect that methodological naturalism will result in accurate information about the world.So methodological naturalism does not lead to philosophical naturalism--the view that the physical world is all their is. Science can tell us about the regularities of nature, but it cannot tell us whether the physical world is all there is.If substance dualism is true, then there are non-physical interventions in the brain. Substance dualism, by itself, doesn't tell us anything about whether there are non-physical interventions anywhere else in the universe, so even if the successes of science could rule out non-physical intervention everywhere else in the universe, that would still be insufficient to rule out substance dualism. The only way to rule out substance dualism would be to exhaustively map the entire causal chain in the brain over some interval of time in which mind/body interactions occur. If there are no causal gaps, then that might justify us in ruling out substance dualism. But there is no computer in the world that could process that much information, so obviously it has never been done. Therefore, the methods of science have not ruled out substance dualism.ConclusionSince both of Pro's arguments are inadequate to substantiate the resolution that "the mind is a purely physical substance," his burden of proof is unmet.