01/24/2013 11:50 am ET | Updated Mar 26, 2013

The Confusion About Souls: Mind, Body and Spirit

Having written a book entitled "The Undying Soul," one might assume that the reader and I both know what exactly the word "soul" means in this context. But actually, there is a lot of confusion about "what a soul is" beyond the conventional ascriptions given for centuries by theologians. Most of us do, in fact, usually have this description in mind when pondering the nature of the human soul; that is, an independent spiritual entity that "coexists" or "cohabitates" with our physical bodies, but then is released to go elsewhere (hopefully heaven?!) when our mortal life ends.

I think this idea has stuck because it actually is the main teaching of both Judeo Christendom as well as Islam.

These great monotheisms offer this teaching largely because it makes life-after-death easy to visualize/comprehend. To be sure, religion is in the business of selling immortality as well as morality, so much so that a religion that does not provide an explanation of an afterlife makes little sense to most Westerners/Middle-Easterners.

This popular description has held sway for centuries, and in Christianity was most famously articulated by one of Catholicism's most celebrated intellectuals, Rene Descartes. Descartes is otherwise famous for no less of an achievement than inventing the standard form of Geometry which bears his name.

Descartes taught that a human being is composed of two utterly separate substances, namely body and soul. The former is made of flesh and bone and the latter, the soul, is completely non-material.

We know this intuitively. Our minds are capable of contemplating the abstract, i.e. the non-material (there are no "square roots" to be found out in the material world), while our bodies are as immersed in the material world of pleasure and pain as they can be. Very, very, few ever had any doubts about this way of understanding our existence over the millennia until the advent of modern medicine. We were comfortable equating our minds with our souls, at least for all practical purposes.

But now we are told that our minds are really just our brains, and our brains are as material as our kidneys and our toenails. Furthermore, philosophers have always been eager to point out that if our souls really are utterly immaterial, as Descartes said, then how does the mind/soul "connect with," i.e. interact with, our material brain?

Neuroscience tells us now that when we talk or see or taste or move, that doing so is the result of neurons in the brain sending or receiving electrical signals biochemically. There seems to be no room in there, nor need for, an immaterial entity like the soul/mind, to make these things happen. No one really thinks that dogs and ducks have souls, but they move and eat and see and reproduce and care for their young, no doubt solely via these same neurochemical/material mechanisms.

There remains to this day an irreconcilable impasse between what religion tells us and what science tells us about mind/soul.

This impasse is what tears at the fabric of our culture, and is what motivated me to put my experiences into a book. Perhaps no person is better equipped to address this conflict than a patient facing a terminal illness. He or she may be a person of faith, but is often directed to leave personal beliefs at the door and allow hard science to do its job. Why should one supersede the other? Isn't it possible that both have an important place in the process? Shouldn't there be room for both? But this is just the beginning of the conversation. Mostly, what I have tried to do is address the impasse as it was occurring to me, and many of my contemporaries, and then move on to my patients. It is the stories of those that are perhaps most dependent upon religions and science that best understand the heart of the issue, and established for me the true existence of the soul, as experienced personally/mystically rather than philosophically/rationally.

In past millennia, science and religion were in agreement, because both acknowledged the existence of God as the underlying reason for our existence. The discoveries of science were always derivative/secondary to God's presence. But over the past century or so, the notion that science had replaced God, has been growing inexorably. Isaac Newton articulated and described his laws of physics in the 17th century as a means of demonstrating God's existence. Now those same laws are used as a reason to believe that the laws exist on their own, just as does reality itself, and there is no need nor room for "God in the equation."

Without a God to "run the universe," there likewise would seem no need for a soul to be at the ground of our own experience. And thus the classic idea that our soul is utterly separate from our body led to a very simple exercise by scientific atheism: get rid of the soul and you will still be left with your body as is, undisturbed by the "loss" of something that was never really there in the first place!

And so now we can see that the possibly erroneous description of the soul that went unchallenged for centuries has led to its own demise. It seems that only in less modern societies, such as those under the authority of fundamentalist Islam, where children are forced to chant and beat their chests for hours every day, can the illusion of the soul be maintained.

But where does that leave the West? Lost and confused no doubt, and certainly lacking the moral clarity of the past. Far worse even, lacking the spiritual clarity needed to face death, which brings us back full circle to my experience with cancer patients and the dilemma they now face for the very first time in human history: facing death without the comfort of knowing, truly knowing, that they are, in fact, creatures endowed with an undying soul.

How can this be remedied? There is only one way: discard the late medieval Cartesian description of the soul (that was produced 1,400 years after Christ) in favor of the ancient description of the soul first advanced by Aristotle 300 years before Christ, which was later refined into a monotheistic framework by Christianity's greatest intellect of all, St. Thomas Aquinas. That is what I believe is not only the best remedy, but the only remedy to resolve this impasse and reunite faith and science, which has been my goal in this project all along.