Students of philosophy are well aware of the watershed significance of Immanuel Kant's epochal work, The Critique of Pure Reason. In this volume Kant gave a comprehensive critique of the traditional arguments for the existence of God, wrecking havoc on natural theology and classical apologetics.
Kant ended in agnosticism with respect to God, arguing that God cannot be known either by rational deduction or by empirical investigation. He assigned God to the "noumenal world," a realm impenetrable by reason or by sense perception.
The impact on apologetics and metaphysical speculation of Kant's work has been keenly felt. What is often overlooked, however, even among philosophers, is the profound impact Kant's critique had on our understanding of the soul.
Kant placed three concepts or entities in his noumenal realm, a realm above and beyond the phenomenal realm. The triad includes God, the self, and the thing-in-itself, or essences. If God resides in this extraphenomenal realm, then, the argument goes, we cannot know anything about Him. Our knowledge, indeed all true science, is restricted to the phenomenal realm, the world perceived by the senses. Kant argued that we cannot move to the noumenal realm by reasoning from the phenomenal realm (a point that put Kant on a collision course with the apostle Paul).
Kant's agnosticism moved beyond theology to metaphysics. Since meta-physics is concerned with that which is above and beyond the physical, it is deemed a fool's errand to seek knowledge of essences. The phenomenal realm is the world of existence, not of metaphysical essences or "things-in-themselves." There may be metaphysical essences but they cannot be known by human reason. That Kant did a hatchet job on metaphysics as well as theology is clear.
Again, what is often overlooked is that the hatchet had more work to do. By assigning the self to the noumenal realm, Kant also hacked away at the concept of the human soul. This has had a devastating impact on subsequent views of anthropology. Pre-Kantian thought gave heavy weight to the importance of the human soul. Post-Kantian thought has as all but eliminated the soul from serious consideration.
The nature of the self remains a concern of psychology, but its nature is enmeshed in enigma. Descartes arrived at a knowledge of the self as a clear and distinct idea via a rigorous doubting process. He resolved to doubt everything he could possibly doubt. The one thing he couldn't doubt was that he was doubting. There was no doubt about that. For anyone to doubt that he is doubting, he must doubt to do it. Since doubting is a form of thinking and thought requires a thinker, Descartes arrived at his famous conclusion: Cogito ergo sum, "I think, therefore I am." We notice that in this formula there is an "I," a self, that is necessarily involved in the process.
Kant, himself, could not rid himself of the awareness of his self. He appealed, however, not to a rational deduction by which he came to a conclusion of his self; rather, he coined the idea of the "transcendental apperception of the ego." This technical language is somewhat cumbersome but nevertheless significant. Kant saw the self not as something perceived by the senses. It is an apperception and a necessary apperception for all thought. It transcends the normal process of knowing according to Kant.
What is crucial is that some notion of the self beyond the physical is inescapable. We may argue about how we know we are selves but we cannot deny that we are selves. Descartes was correct: It takes a self to deny the self.
That the human self involves more than the body is clear to all except the most rigorous material determinists who reduce all reality to the purely physical, including thought as mind itself. They reject the Gerstnerian formula: "What is mind? No matter. What is matter? Never mind."
Classical Christian anthropology views man as a substantial dichotomy. This concept is likewise under attack in evangelical circles, not only from the side of trichotomists but also from those who see in it an unwarranted intrusion of Greek philosophy into Jewish-Christian thought. It is rejected by Murray Harris, for one, and was attacked by Philip Hughes, to mention another evangelical scholar.
In my judgment, the rejection of substantial dichotomy rests upon a fundamental error of understanding, a fatal false assumption. Harris and others attack substantial dichotomy because they hear in it a recapitulation of Greek dualism. The Greeks viewed man as a creature locked in a conflict between two opposing and irreconcilable substances, the body and the soul. To the Greek the soul is eternal and good, the body is temporal and intrinsically imperfect. For Plato the nonmaterial ideal realm is the realm of the good. The physical is at best an imperfect receptacle or copy of the ideal. Hence the view emerged in Greek philosophy that the body is the prison house of the soul. Redemption means the release of the soul from the body.
Pythagoras was the source of Plato's theory of the transmigration of the soul, an early version of reincarnation. The soul is eternal but may become entrapped in a series of incarnations during its eternal migration. Redemption occurs when the chain or series of incarnations end and the soul is free to live a bodiless existence.
Herein is the dualism so repugnant to Christian thought. But the problem with the Greek view is not that it has two distinct substances, body and soul, but that it views them as in total conflict with each other, because the physical is inherently evil (at least in the metaphysical sense of evil).
Jewish-Christian thought, however, sees man as made up of two distinct substances that are not in conflict. Nor does the Bible view matter as being inherently evil. For the Christian, redemption is of the body, not from the body. The Christian doctrine of substantial dichotomy is not dualistic. Man is not a dualism but a duality. That is, we have a real body (material substance) and a real soul (immaterial substance). There is an analogy with the person of Christ in that He has two natures or substances, divine and human, united in one person. That He has two substances does not necessitate a dualism in His person. (Of course the human nature of Christ also includes a human body and a human soul.)
That we are made up of body and soul is indicated in the creation account:
"And the Lord God formed man from the dust of the ground, and breathed into his nostrils the breath of life, and man became a living soul" (Genesis 2:7).
In the creation imagery man's body is formed first. But the body without the soul remains lifeless. When God breathes the breath of life into the body, then man becomes a living soul. In this account there is no hint of an eternal or preexistent human soul. The soul is as much a creation as is the body. That the soul survives the grave is not a testimony to its indestructibility or of its intrinsic immortality. The soul as a created entity is mortal. It survives the grave only because it is sustained and preserved by the power of God. It is preserved for eternal felicity for the redeemed; it is preserved for eternal punishment for the damned.
The soul of man can live without the body; the body cannot live without the soul. Jesus exhorted His hearers: "Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the one who can destroy both the soul and the body in hell" (Matthew 10:28).
From biblical revelation we know we have souls. The Bible does not banish the soul to some "never-never" noumenal world of agnosticism. Not only do we have souls, but the nurture and care of our souls is a top priority for the Christian life.