 What happens when we die? Is there some part of us that persists beyond death? The search for the soul is an ancient pursuit, dating back at least as far as the great philosophers who suppose there must be some unchanging aspect to human existence. Almost all cultures on earth have some belief in an intangible part of the person that persists beyond death. The work of Rene Descartes explores the concept more fully, and has changed the debate to one about the possible duality of mind and brain, body and soul. In a recent debate, Thunderfoot and Ray Comfort reached a fundamental disagreement on this point. I am certainly no expert on the topic, but I would like to explore the idea of mind-brain duality from the perspective of a scientist with an open-minded position about God. That is, on the evidence I neither fully accept nor fully reject that God could exist. I invite you to offer your own perspective on the soul in the comments. Please no censoring attacks or rudeness and yes, I realize what a crazy request that is on YouTube. I think we benefit from an honest, open exchange of ideas. I'm especially interested in the logical, reasonable approaches to the problem. Before we actually get to the issue of mind-brain duality, I'd like to find a common ground on some definitions. First, emergent properties. Emergent properties are those properties that emerge from a system of high complexity that do not exist individually in the simpler components. For example, and I think this is relevant, a single neuron does not have the property of intelligence, but the large collection of neurons in our brains apparently do. This is true of things like language or DNA sequences or an ant colony. Relatively complex behaviors can arise out of relatively simple interactions. It's one of the more fascinating phenomenons in nature and can be observed on many scales. Second, objective versus subjective. An objective property is one which is independent of the observer. It's a hard concept to pin down, but in general anything which can be arrived at logically, with an observation of evidence, is objective. Subjective properties are dependent on the observer. We might call this opinion, but I think that's a narrow subset of subjective properties. As a very outset, I want to discard purely scriptural definitions of the soul. These are by their nature subjective, and this is one of the things I objected to most about the position of Ray Comfort and then later Venomfang X. There is nothing clear or objective about the scriptural description of the soul. I suspect that even a Jewish rabbi about 30 AD would not share the same precise definition of soul that Ray Comfort and Venomfang X do. That's the problem with ancient holy books. They get reinterpreted by new generations of theologians. Even within the biblical, literalist Christian sects, we would not have perfect agreement on the definition of a soul or mind. So if we set aside purely scriptural definitions, what can we say objectively about the soul? I think some of us at least would agree with the following defining characteristics. 1. It is eternal. 2. It is immaterial. That is, it's not made of material. 3. It contains the sense of self or self-awareness. 4. It contains the personality and or the morality. 5. In some capacity, it acts on or originates our thoughts. Eternal and immaterial are unfortunately not properties that I can think of a way to test or even logically arrive at. The sense of self or self-awareness is a little bit easier. Francis Crick documents in his book The Astonishing Hypothesis that organic brain damage can result in changes in both self-awareness and the ability to make spontaneous choices, the so-called free will. Likewise for personality and morality, it is well documented that electrical stimulation of specific areas of the brain can produce amoral or aggressive behavior in animals and humans. Organic brain injuries and tumors have been documented to radically alter a patient's behavior and outlook. What can we logically conclude from those facts? It certainly doesn't rule out the existence of a mind-brain duality, but it does say that the brain alone, that is, the physical operation of the neurons in the brain, is sufficient to generate some of the functions we attribute to the soul, and also that the capacity of the soul is apparently not sufficient to overcome physical damages to the brain. I think objectively it's a fair conclusion that if a mind or soul exists, and there's apparently no way to test for that, but if it exists, it cannot act independently of the brain. I want to propose a slightly different model that incorporates the objective reality, as well as the subjective possibility. I propose a tripartite division of brain, mind, and soul. Soul in this context has a purely spiritual meaning, to be ascribed subjectively by people of faith as an eternal part of existence. Mind, the originator of thought, free will, emotion, and ethical choice, is an emergent property of the biological brain. It is at the same time the simple electrical discharges moving around a bionural net, and also the emergent behavior of a sentient being capable of thought, decision, self-awareness, and ethicality. The advantage of such a definition, while it may not satisfy some interpretations of scripture, is that it neatly separates the subjective, spiritual aspect of mind-brain duality from objective definitions that are important in matters of medical ethics, and of life, brain death, severe organic brain damage, and so forth. Why are scientists and doctors, people like Thunderfoot, so reductionist about such matters? Why do they insist on purely materialistic answers to these questions? Picture this. A patient presents at a local emergency room with a frothing mouth screaming in anger with dilated pupils. On his list of possible treatments, would you prefer the treating physician to attempt an exorcism or a talk screen and cranial MRI? Should he treat the patient with materialistic medicine or faith-based prayer? It's not a trivial question, really. It's only been in the last five to ten generations, and only in the developed world, that the answer seems obvious. I leave it up to the viewer whether we have benefited from a materialistic approach to science, technology, and medicine, or if these areas were better served under previous faith-based approaches. I look forward to reading your comments, and please vote. Thanks for watching.