These are simply my rambling thoughts on a very difficult question someone posed to me recently. I doubt that I will present any “new” arguments here, but below is basically what I believe on this subject. I hope some might find it helpful.
As we approach this subject, I believe the first question should rather be, “Can I know anything with absolute certainty?” In the absolute sense, it is impossible for us to be certain of anything beyond the smallest shadow of doubt. In that sense we cannot absolutely prove that God exists, that man possesses a soul, or even for that matter that man himself exists. Often materialists demand of the religious believer a degree of proof in religious matters that they do not demand of science itself. What we must ask, whether we are discussing a religious/spiritual tenet or a scientific theory/fact, is whether it is possible to know within a reasonable degree of reliability whether the subject in question is true or not. For instance, we cannot know absolutely that by dropping a metal ball from the top of a 20-story building the ball will always fall downward and strike the earth. But in the long history of mankind we have never known a heavy object to do otherwise, and thus we may conclude with a reasonable degree of certainty that gravity exists and that it will behave in a similar fashion in all such experiments indefinitely. That is not absolute proof, but it is the best we can hope for and is that on which we base our day-to-day living. One cannot assume (nor expect to live very long) that if one jumps from the top of a tall building he just might fly upward instead of falling downward as all previous evidence points, but we can know that the reasonable expectation of such action will direct one quickly to the ground and likely to one’s death.
It is with that degree of knowledge or expectation of proof that one should approach topics such as that of the soul. We basically must hold to the same standard as required in a court of law, that we can know something “beyond a reasonable doubt” — not beyond all possible doubt, but beyond a reasonable doubt.
Such is the case for the argument of the existence of God. We are not asked to believe in God on the basis of faith alone, without any evidence whatever (despite the protestations of many well-meaning but uninformed Christians), but we can indeed prove the existence of God to a reasonable degree of certainty. Can we offer absolute proof? No. But we can offer evidence enough to establish God’s existence with a reasonable certainty. Beyond that there comes a place at which we must engage faith, but it is important to remember that this is the case not only of religious truth but also of scientific truth. Science can lead us far into the explanation of many things, but there eventually comes a point at which we must take the evidence on face value and beyond that must engage faith in the belief that our evidence is true and reliable. Those who present evidence that there is no God, that the universe exists and came to its present state by blind chance and is without meaning, may indeed offer some evidences to point in that direction; but where science ends they must then accept as a faith assumption the belief that the rest of their position is true. To my mind it requires a much stronger faith in nothingness to believe there is no Creator or some kind of intelligent force behind the universe than it does to accept that there is. Which faith is more substantial?
Scripture itself does not ask to be accepted on faith alone. Constantly we are challenged within the sacred texts to test and verify. Scripture’s own definition of faith is that it is “the evidence of things hoped for,” not “the proof of things believed.” This does not imply, however, as some maintain, that what we must have is faith in spite of the evidence to the contrary, but that our faith must be based on the reality of what we can observe in the universe as it exists. I believe that is why God set the Scriptures within the context of history so that the facts it presents that can be subject to verification lend credibility to the things it discusses which are beyond the scope of objective inquiry.
But back to the topic at hand, as I see it there are three kinds of evidence that we could consider to try to determine whether man possesses a soul as distinct from the brain and neural pathways: scientific evidence, philosophical evidence, and religious evidence. No one branch of inquiry could necessarily offer the proofs we may require, so I believe it is vital to consider all three in this discussion.
Scientific Evidence. By definition the soul, if it exists, exists outside the physical and material realm, and therefore it is doubtful that it could be subjected to any reliable scientific analysis. To the materialists, this is one of the strongest reasons they resist acknowledging its possible existence. To those who believe we live in a closed universe that consists of literally nothing more than what can be measured or known through science, the idea that there may be another plane of existence beyond the material realm is discounted out of hand. While I certainly understand this skepticism, it seems to me that this only makes materialists quite unscientific in that they reject alternative hypotheses without sufficient grounds for doing so. To my way of thinking genuine science leaves open all possibilities which then must be studied and weighed before being rejected or accepted.
Having said that, I readily concede that there likely is little material scientific evidence that could be proffered for the existence of the soul, at least from the standpoint of scientific inquiry alone. What evidence there is exists almost entirely anecdotally, though perhaps in combination with other evidences from philosophy and religion they may be shown to have some small degree of credibility. Among the evidences with which I am familiar are the following.
I am aware of one scientist’s attempt to weigh the soul. This admittedly dubious experiment was conducted by weighing the bodies of people near death and then again immediately after death. Reportedly the results did indicate a very slight loss of weight of the material body shortly after death, though these results are subject to many variables. The difference in weight could be attributed to the exhalation of oxygen from the lungs, the cessation of small bodily movements on the scales, or perhaps other factors unrelated to the departure of a spiritual entity from the body. I hold little meaning to this study since, again by definition, there is no reason to suspect that a spiritual body could be measured by material standards. I mention it only because it has been attempted, but I do not credit it with any degree of reliable evidence for the existence of the soul.
Also we may consider the anecdotal evidence of countless reports of people who claim to have seen or otherwise encountered spirits of the dead. Because this evidence too is merely anecdotal and cannot be conclusively verified I do not grant it much status, though the number of such reports throughout history and across all social strata does make it worth consideration and further study.
Perhaps the best “scientific” evidence for the soul is the number of reports of what are called “near-death experiences,” which also cross all religious and societal borders. Again, this evidence is largely anecdotal, but it is rather substantial and has been reported by literally thousands of people, many of whom were former skeptics. Typically these experiences have been reported occurring during periods when all life functions have ceased in an individual, even in those with flat brain waves. People who have had these experiences often can relate seeing and hearing everything that transpired in the room where their bodies lay during a time when no measurable physical activity could account for their perceptions. When brain waves are flat, such measurement indicates an absence of all cortical activity. If these people are merely extrapolating their perceptions of things into an imagined scenario, then there would be some cortical activity going on as their ears (at least) registered the input of external stimuli. That these individuals often can relate excatly everything that was said and done around them during a period when all cortical activity was at zero would seem to imply that they were able to perceive these events through means other than the purely physical. While certainly not proof of a soul, such reports certainly lend some degree of credibility to the concept.
Philosophical Evidence. To my way of thinking the philosophical evidence is considerably stronger. Since the beginning of recorded history man has believed he possessed a soul that is distinct from the material body. It is arguable that it is impossible for man to conceive of an idea that does not, in some form or other, exist. It is felt by many that whatever man may devise must be based on some truth of what is. Though his perception could well be grossly distorted from the reality, it nonetheless is based on a principle of truth that is real. While not the strongest argument perhaps, it bears mentioning.
Beyond the mere existence of the soul, man also has believed himself distinct from the rest of creation in that he possesses a moral consciousness. No other living thing shows evidence of possessing this, nor has any other creature devised the concept of God or developed religion. Animals, even to the highest primates, act within established parameters determined by their species. Man, however, exhibits free will. Materialist claims for an explanation of free will have been proffered, but to my mind they all stand wanting. Genetic determinism leaves no room for free will but insists that we all act and behave according to predetermined codes established by our genetic makeup. Animal behaviors are largely predictable, but man’s is not. Yet if determinism is correct, how does it explain communication and the exchange of disparate ideas? If all men acted generally in the same way, as do animals, and if they all believed the same things, there might be some strong support for a deterministic universe. But since we do not, this offers evidence for free will ... and hence, evidence for a part of our make-up that is beyond the neural and physical alone. The concept of the soul could explain free will, but as I see it materialistic determinism cannot.
A further philosophical point will be considered in conjunction with the religious evidence below.
Religious Evidence. While the skeptic will automatically eschew religious evidence as unreliable, I believe it cannot be entirely discounted without consideration. Elsewhere we have established that there are credible evidences for the existence of a Creator. If we accept the proposition that God may exist, it is not unreasonable to believe that this God would have communicated to His creation (man). I believe He has done so, and the bulk of that communication is recorded in Scripture. As stated above, He did not set this communication in a vacuum and ask us to accept it on blind faith, but instead He posited it in the context of history, rendering it verifiable in many aspects. If we could find that its historical and geographical contents were inaccurate, then we would have no reasonable basis for accepting its statements of things we cannot verify. But if instead we could find that in all areas where its information about things we can verify are accurate, that lends credibility to its statements that are not immediately verifiable. In other words, because of the manner in which this communication has taken place, I can accept on faith that what it tells me about the spiritual world (which I cannot see) is reliable and true, just as I can accept on faith the reports of people whom I have learned to be truthful in the things I can verify when they relate details about places or events they have seen that I have not. Scripture tells me I have a soul, and while I should not be expected to accept that simply on its word alone, I can accept it when I consider that what it tells me about verifiable data also is reliable. Furthermore I can compare its claim with what I can know from science and philosophy. The claim that the soul exists is, at the least, reasonable, and goes far to explain the philosophical concepts already discussed. This is more than the old adage, “The Bible says it, therefore I believe it.” I believe it because other things the Bible has told me about man, about history, about geography, and about other such things can be shown to be reliable. While I cannot verify its claim in the area of metaphysics in the same manner as I can the physical, I nevertheless can accept it as a plausible claim based on the other factors that can be known and verified.
The materialist believes the world exists as the result of blind chance and that we are nothing more than the sum of our molecules, without design, without meaning, without purpose. It is all chance. Therefore, let us consider chance.
Suppose the materialists are correct in that I have no purpose for existence, and yet I live my life in conformity to Christian standards. Other than believing something that is not true, what practical harm is there in that for me? Would it really matter if I believed a lie? I cannot see that it would, because in a world without meaning truth is equal to non-truth, so it would not matter what I believed or did. If at the end of my life I simply ceased to exist, would my life have been more rewarding if I had adopted a nihilistic view and lived only for myself, behaving in a manner in which nothing at all mattered and all was meaningless? Even the existentialists insist that we must find our own personal meaning for life, though they maintain that whatever meaning one finds is ultimately meaningless anyway. If I find “meaning” through Christianity, is that worse than admitting to nothingness in its entirety? Other than the possibility that I may have to give up my life as a martyr for my beliefs or may not experience some things I might allow myself if I believed there was no point to morality or life, I cannot see that I would be any worse off living a lie as I would if I abandoned all meaning. It would all be pointless anyway.
But let us flip the coin and assume that Christianity is true after all and that I do possess a soul that will continue existence beyond my physical death. In that case would it matter whether I endeavored to live my life by Christian standards or instead chose to abandon meaning because I wasn’t satisfied with the degree of evidence provided me? Is that a chance I am willing to take?
I admit that belief in God and in the soul of man is ultimately a matter of faith. But as I have explained, it is far from a blind or unreasonable faith. The latter is the kind of faith the pagan gods ask for, but not the kind of faith I am called to bear. And faith is not limited only to our religious convictions. As already pointed out, all systems require a degree of faith at some point as it is impossible to impirically verify all truths. The scientist must hold onto the faith that his science (and his understanding of it) is accurate. The nihilist must have a faith in nothingness. It is not a matter of whether I am to accept faith or reason, but rather is how I will determine what is my reasonable faith. The Christian doctrine of the soul seems to me far more reasonable, based on the evidence of what I can see and know, than the idea that we are merely the sum total of our molecules. At the very least my belief system gives me more meaning than any other I know, and even the existentialists cannot argue against that. But I personally believe it is far more than an establishment of existential meaning. I believe it is true.