(I conclude my case for the soul)
Two last objections to the existence of the soul are related to science. First, the predominant scientific theory of origins is evolutionary theory; in that we are the product of wholly physical processes through chance and time. On this view there is no room (or need) for immaterial substances. On strict physicalism, something like the soul cannot come from purely physical material or the physical processes on that matter – all that results is a more complicated arrangement of physical matter. This objection is clearly question begging as it assumes that physicalism is true. If there is good evidence that physicalism is false (which I have provided), it then follows that evolutionary theory is incorrect in that we are not merely the product of naturalistic evolutionary processes.
Second, scientific evidence also has shown that dualism is untenable because of many faculties dependent upon physical processes that were once attributed to the soul. As previously quoted, Christian physicalist Nancey Murphy notes that since science has provided so much evidence to explain life and consciousness, we do not need another entity (such as the mind or soul). I have stated beforehand that the idea that science provides our only knowledge (scientism) is self-refuting so that even if science can only stipulate physical substances, this still leaves the possibility of other entities existing and other ways to obtain knowledge of them. What is evident is that science itself cannot resolve the central issues regarding the mind (e.g. what are thoughts, feelings, or beliefs?), but that this is a matter best left for philosophy. Science can answer questions about physical properties in physical material objects (e.g. brain states), but it cannot answer questions about the nature of mental states. Chistof Koch and Nobel prize winner Francis Crick (both physicalists) acknowledge this and comment on the mind/body problem suggesting that “scientists should concentrate on questions that can be experimentally resolved and leave metaphysical speculations to ‘late-night conversations over beer’”
Since science cannot address this issue, behind these criticisms lie the real reasons for rejecting a substance dualist view; namely the a priori acceptance of naturalism or more succinctly methodological naturalism. This methodology only accepts natural causes for any observable events, thus excluding the immaterial before it even starts. Substance dualism is dismissed out of hand with nary a reason because “enlightened people don’t think that way anymore.” Not only is this attack ad hominem, but it is a sign of weakness for the physicalist case.
John Searle, a prominent naturalist philosopher of the mind, outlines another reason for the aversion to substance dualism, claiming, “Acceptance of the current [physicalist] views is motivated not so much by an independent conviction of their truth as by a terror of what are apparently the only alternatives.” Naturalists are so appalled by supernaturalist alternatives that they would rather pursue theories that support physicalism than be open to other evidence or conclusions. Perhaps this is because, if you can prove the existence of finite immaterial minds, this in turn could lead to the inferential conclusion (best explanation) that the universe has a Divine Mind as its source, thus proving naturalism untenable.
From a Christian worldview, the importance of defending substance dualism cannot be underestimated. The Bible is clear that some sort of anthropological dualism is correct and our eschatology explicitly demands a substance that survives death. This is not to say that we should defend a view that is unreasonable, but as I have shown, there is ample evidence for substance dualism against the physicalist view. If substance dualism is correct, then the knowledge that we are spiritual beings should permeate every part of our lives because we live in a spiritual world. As Paul states, “Those who live according to the sinful nature have their minds set on what that nature desires; but those who live in accordance with the Spirit have their minds set on what the Spirit desires.” (Romans 8:5)
The view one takes also has ethical implications. As I have already shown, it is difficult on a physicalist view to account for libertarian free will, and if determinism prevails, why should we hold anyone accountable for their actions? Physicalism also has been shown it cannot commit to a strict sameness of person through change which means that we would be remiss to hold some “property thing” accountable for past actions after it has changed, e.g. the “property thing” we call Scott Peterson who murdered his wife in 2002 is not the same “property thing” we call Scott Peterson now, but is serving for the first Scott Peterson’s crimes nonetheless. Last, our view of a person affects ethical issues such as abortion, reproductive technologies, euthanasia, and human cloning. For instance, a substance view of persons disallows the possibility of potential persons or human nonpersons, i.e. human fetuses are immature persons, not potential persons.
Although this view (i.e. the soul’s existence) has become unpopular in our modern culture, I have shown that this is unwarranted intellectually. I began by briefly outlining the different views of the mind and body, adopting Thomas Aquinas’ dualistic version. Since science is not our only source of knowledge, theological knowledge was provided from the Bible which clearly advocates an eternal soul that survives death and will be reunited with a resurrected body eventually. Next, multiple independent philosophical arguments were given to support substance dualism while demonstrating that physicalism is an inferior model. It is evident that mental states are not equivalent to physical states; not only from their natures but from our own introspection as well. Our personal identity through change and our normal conception of free will are also better explained under a dualist view. I then addressed the main philosophical and scientific objections against substance dualism and established that the problems were either exaggerated or motivated by a priori commitments to scientism or methodological naturalism. Last, I explained why our view of human persons is important, especially when it comes to morality.
As Christians, we are fortunate that theist philosophers (such as Moreland, Rae, Willard and others) have taken up the challenge of defending substance dualism in the face of the physicalist challenge. Substance dualism is the commonsense view as well as the intellectual view of most theologians and philosophers from any culture or time period (excluding the present) for good reason. It can explain consciousness and other mental properties much easier. Even naturalistic philosopher of the mind, John Searle laments that “the leading problem in the biological sciences is the problem of explaining how neurobiological processes cause conscious experiences.” Substance dualism has no such problem.
 Ibid., 49-50.
 Ibid., 50.
 Nancey Murphy, “Human Nature: Historical, Scientific, and Religious Issues,” in Warren S. Brown, Nancey Murphy, and H. Newton Malony, Whatever Happened to the Soul?, 18.
 J.P. Moreland, What is the Soul? Recovering Human Personhood in a Scientific Age, 51.
 Cf. John Horgan, “Can Science Explain Consciousness?” Scientific American (July 1994): 91.
 John Searle, Rediscovering the Mind (Cambridge, Mass.: MIT Press, 1992), 3-4.
 Dallas Willard, The Divine Conspiracy, 82.
 J.P. Moreland and Scott B. Rae, Body & Soul, 119.
 John Searle, “The Mystery of Consciousness: Part II,” New York Review of Books (16 Nov. 1995), 61.