CHRISTIANITY AND PHILOSOPHY
CHAPTER FIFTEEN Page 66
THE WORLD BEYOND OUR SENSES: KANT AND THE LIMITS OF REASON
“We shall be rendering a service to reason should we succeed in discovering the path upon which it can securely travel.”—Immanuel Kant, Critique of Pure Reason
SO FAR WE HAVE BEEN CONSIDERING science and the scientific understanding. Now I want to broaden the inquiry to examine the proudest boast of the modern champion of secularism: that he is an apostle of reason itself. What distinguishes the “freethinker,” Susan Jacoby writes in her book of that title, is a “rationalist approach to fundamental questions of earthly existence.” Taking reason as his star and compass, the atheist fancies himself superior to the rest of the people who rely on faith, superstition, and other forms of irrationality Sam Harris writes, “Tell a devout Christian that his wife is cheating on him, or that frozen yogurt can make a man invisible, and he is likely to require as much evidence as anyone else, and to be persuaded only to the extent that you give it. Tell him that the book he keeps by his bed was written by an invisible deity who will punish him with fire for eternity if he fails to accept its every incredible claim about the universe, and he seems to require no evidence whatsoever.” But there is one subject on which the atheist requires no evidence: the issue of whether human reason is the best— indeed the only—way to comprehend reality. Writing in Free Inquiry, Vern Bullough declares that “humanists at least have reality on their side.” Paul Bloom asserts in the Atlantic Monthly, “Yes, our intuitions and hypotheses are imperfect and unreliable, but the beauty of science is that these ideas are tested against reality.” Steven Weinberg writes that as a scientist he has a “respect for reality as something outside ourselves, that we explore but do not create.” In pursuing knowledge, he writes, “the pull of reality is what makes us go the way we go.” E. O. Wilson writes that “outside our heads there is a freestanding reality” whereas “inside our heads is a reconstitution of reality based on sensory input and the self-assembly of concepts:’ By linking the two, Wilson hopes to achieve what he calls “the Enlightenment dream” of “objective truth based on scientific understanding.” Weinberg, Wilson, and other atheists may not recognize it, but there is a huge assumption being made here. These men simply presume that their rational, scientific approach gives them full access to external reality. It is this presumption that gives atheism its characteristic arrogance. Daniel Dennett and Richard Dawkins call themselves “brights” because they think they and their atheist friends are simply smarter than the community of religious believers. In this chapter I intend to show that this arrogance is misplaced. The atheist or “bright” approach to reality must be measured against a rival approach. Through the centuries the great religions of the world have held that there are two levels of reality. There is the human perspective on reality, which is the experiential perspective— reality as it is experienced by us. Then there is the transcendent view of reality, what may be called the God’s-eye view of reality, which is reality itself. Being the kind of creatures that humans are, we see things in a limited and distorted way, “through a glass darkly,” as Paul writes in his first letter to the Corinthians 13:12. Indeed we can never, as long as we are alive, acquire the God’s-eye view and see things as they really are. Rather, we live in a fleeting and superficial world of appearances, where the best we can do is discern how things seem to be. We can, however, hope that there is a life after death in which we will see everything—including God—as it really is. Which of these two views—the atheist view or the religious view— is correct? Engaging the argument on the ground chosen by the atheists, the ground of empiricism and reason alone, I intend to show that the religious view is the right one. There is more than one way to do this, but I have chosen the way illuminated by philosopher Immanuel Kant. Kant seems an appropriate choice because he is considered the greatest of modern philosophers. Kant was a leading figure of the Enlightenment, a man of science and philosophy, and he showed what may be termed the Enlightenment fallacy. This is precisely the fallacy that has duped many modern atheists and “brights.”
In his book The World as Will and Idea, philosopher Arthur Schopenhauer writes, “Kant’s teaching produces a fundamental change in every mind that has grasped it. The change is so great that it may be regarded as an intellectual rebirth…. In consequence of this, the mind undergoes a fundamental undeceiving, and thereafter looks at things in another light.” The greatness of Kant is that he takes our most fundamental assumptions and turns them into questions. We think we are on the ground floor of awareness, but Kant shows us a whole different level beneath it that we can examine. Before Kant, most people simply assumed that our reason and our senses give us access to external reality—the world out there—and that there is only one limit to what human beings can know That limit is reality itself. In this view, still widely held by many in our society, human beings can use the tools of reason and science to continually find out more and more until eventually there is nothing else to discover. The Enlightenment fallacy holds that human reason and science can, in principle, gain access to and eventually comprehend the whole of reality. In his Critique of Pure Reason, Kant shows that these assumptions are false. In fact, he argues, there is a much greater limit to what human beings can know. In other words, human reason raises questions that—such is the nature of our reason—it is incapable of answering. And it is of the highest importance that we turn reason on itself and discover what those limits are. It is foolishly dogmatic to go around asserting claims based on reason without investing what kinds of claims reason is capable of adjudicating. Reason, in order to be reasonable, must investigate its own parameters. Kant begins with a simple premise: all human knowledge is based on experience. We gain access to reality through our five senses. This sensory input is then processed through our brains and central nervous systems. Think about it: every thought, even the wildest products of our imagination, are exclusively based on things that we have seen, heard, touched, smelled, or tasted. If we imagine and draw creatures from outer space, we can give them four eyes and ten legs, but ultimately we have no way to conceive or portray them except in terms of our human experience. It is an empirical fact that our five senses are our only lenses for perceiving reality. Now Kant asks a startling question: how do we know that our human perception of reality corresponds to reality itself? Most philosophers before Kant had simply taken for granted that it does, and this belief persists today. So powerful is this “common sense” that many people become impatient, even indignant, when Kant’s question is put to them. They act as if the question is a kind of skeptical ploy, like asking people to prove that they really exist. But Kant was no skeptic: he saw himself as providing a refutation of skepticism. He knew, however, that to answer skepticism one has to take the skeptical argument seriously. The way to overcome skepticism is by doing justice to the truth embodied in it. Kant’s goal was to erect a dependable edifice for knowledge on the foundation of extreme skepticism. Kant’s question about the reliability of human perception has been the central preoccupation of Western philosophy since Descartes. How do we know what we claim to know? Locke had famously pointed out that material objects seem to have two kinds of properties, what he called primary properties and secondary properties. Primary properties are in the thing itself, whereas secondary properties are in us. So when we perceive an apple, for example, its mass and shape are part of the apple itself. But Locke ingeniously pointed out that the redness of the apple, its aroma, and its taste are not in the apple. They are in the person who sees and smells and bites into the apple. What this means is that our knowledge of external reality comes to us from two sources: the external object and our internal apparatus of perception. Reality does not come directly to us but is “filtered” through a lens that we ourselves provide. Philosopher George Berkeley radicalized this mode of inquiry: “When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas.” Berkeley’s argument was that we have no experience of material objects that exist outside the perceptual apparatus of our mind and senses. Both the primary and the secondary qualities of objects are perceived in this way. We don’t experience the ocean, we experience only our image and sound and feel of the ocean. Berkeley famously concluded that we have no warrant for believing in a material reality existing independent of our minds! The great Samuel Johnson famously “refuted” Berkeley by kicking a rock. There! The rock exists! Alas, this is no refutation. Berkeley’s reply to Johnson would be that his entire experience, from perceiving the rock to the sharp pain he felt upon kicking it, occurred entirely within his mind. And Hume completed Berkeley’s skeptical argument by applying it to human beings themselves. We have no experience of ourselves other than our sensations and feelings and thoughts. While we know that sensations and feelings and thoughts exist, we have no basis for postulating some “I” behind them that is supposed to be having those reactions. It was Hume, Kant wrote, who awakened him from his “dogmatic slumber.” Kant conceded Berkeley’s and Hume’s point that it is simply irrational to presume that our experience of reality corresponds to reality itself. There are things in themselves—what Kant called the noumenon —and of them we can know nothing. What we can know is our experience of those things, what Kant called the phenomenon. If you have a dog at home, you know what it is like to see, hear, smell, and pet it. This is your phenomenal experience of the dog. But what is it like to be a dog? We human beings will never know. The dog as a thing in itself is hermetically concealed from us. Thus from Kant we have the astounding realization that human knowledge is limited not merely by how much reality there is out there, but also by the limited sensory apparatus of perception we bring to that reality.
Consider a tape recorder. A tape recorder, being the kind of instrument it is, can capture only one mode or aspect of reality: sound. Tape recorders, in this sense, can “hear” but they cannot see or touch or smell. Thus all aspects of reality that cannot be captured in sound are beyond the reach of a tape recorder. The same, Kant says, is true of human beings. We can apprehend reality only through our five senses. If a tape recorder apprehends reality in a single mode, human beings can perceive reality in five different modes: sight, hearing, smell, taste, and touch. There is no other way for us to experience reality. We cannot, for example, perceive reality through sonar in the way that a bat does. Our senses place absolute limits on what reality is available to us. Moreover, the reality we apprehend is not reality in itself. It is merely our experience or “take” on reality. Kant’s point has been widely misunderstood. Many people think that Kant is making the pedestrian claim that our senses give us an imperfect facsimile or a rough approximation of reality. Philosophical novelist Ayn Rand once attacked Kant for saying that man has eyes but cannot see, and ears but cannot hear—in short, that man’s senses are fundamentally deluded. But Kant’s point is not that our senses are unreliable. True, our senses can fool us, as when we see a straight twig as bent because it is partly submerged in water. Human beings have found ways to correct these sensory distortions. Kant is quite aware of this, and it is not what he is after. Kant’s argument is that we have no basis to assume that our perception of reality ever resembles reality itself. Our experience of things can never penetrate to things as they really are. That reality remains permanently hidden to us. To see the force of Kant’s point, ask yourself this question: how can you know that your experience of reality is in any way “like” reality itself? Normally we answer this question by considering the two things separately. I can tell if my daughter’s portrait of her teacher looks like her teacher by placing the portrait alongside the person and comparing the two. I establish verisimilitude by the degree to which the copy conforms to the original. Kant points out, however, that we can never compare our experience of reality to reality itself. All we have is the experience, and that’s all we can ever have. We only have the copies, but we never have the originals. Moreover, the copies come to us through the medium of our senses, while the originals exist independently of our means of perceiving them. So we have no basis for inferring that the two are even comparable, and when we presume that our experience corresponds to reality, we are making an unjustified leap. We have absolutely no way to know this. It is essential, at this point, to recognize that Kant is not diminishing the importance of experience or of the phenomenal world. That world is very important, if only because it is all we have access to. It constitutes the entirety of our human experience and is, consequently, of vital significance for us. It is entirely rational for us to believe in this phenomenal world, and to use science and reason to discover its operating principles. A recognized scientist and mathematician, Kant did not degrade the value of science. But he believed science should be understood as applying to the world of phenomena rather than to the noumenal or “other” world. Many critics have also understood Kant to be denying the existence of external reality. This is emphatically not the case. Kant is not a skeptic in that sense. Other philosophers, such as Johann Fichte, went down that road, but Kant did not. For Kant, the noumenon obviously exists because it gives rise to the phenomena we experience. In other words, our experience is an experience of something. Moreover, Kant contends that there are certain facts about the world—such as morality and free will—that cannot be understood without postulating a noumenal realm. Perhaps the best way to understand this is to see Kant as positing two kinds of reality: the reality that we experience and reality itself. The important thing is not to establish which is more real, but to recognize that human reason operates only in the phenomenal domain of experience. We can know that the noumenal realm exists, but beyond that we can know nothing about it. Human reason can never grasp reality itself. So powerful is Kant’s argument here that his critics have been able to answer him only with what may be termed the derision of common sense. When I challenged Daniel Dennett in a Wall Street Journal article to debunk Kant’s argument, he posted an angry response on his Web site in which he said that several people had adequately refuted Kant. But he didn’t provide any refutations, and he didn’t name any names.” Basically, Dennett was relying on the argumentum ad ignorantium, the argument that relies on the ignorance of the audience. He was hoping that his admirers would take it on faith that such refutations exist somewhere in the literature. In fact, there are no such refutations. Kant’s ideas are so counterintuitive that they produce an almost visceral resistance. The notion that reality might be completely different from how it presents itself to us seems absurd, unreal, and impossible to take seriously. We resist Kant emotionally, no matter how compelling his argument. Normally reasonable people like Dennett respond to Kant with evident impatience. They are unable to answer his argument, but they pretend that it is not necessary to answer it. This attitude may be termed the “fundamentalism” of reason. It is reason so sure of itself that it refuses to consider reasonable criticism. Reason has become irrational and now relies entirely on simple intuition or “common sense.” Common sense, however, is not always a reliable guide to the truth. Common sense tells us that the earth is stationary and that the sun goes around it. Common sense tells us that an object is naturally at rest and that a moving object must automatically come to a stop. Common sense tells us that space and time are absolute. All these simple intuitions are false. In fact, the great discoveries of modern science—from Copernicus to Galileo to Newton to Einstein to Bohr to Heisenberg—are all massive violations of common sense. That is why in several cases the geniuses who first put forward those ideas were dismissed as crackpots. We now know that these crackpots were right. So it is a fact, not a matter of opinion, that reality is sometimes very strange and that common sense does not give us an unfailingly accurate picture of the world. To proclaim that it always does is to expose oneself as an ignoramus. Common sense, philosopher Bertrand Russell once said, is the “metaphysics of savages.” Kant recognized that he was producing a revolution in human understanding. Just as Copernicus had turned the world “upside down” and forever altered the way we perceive the earth in relation to the sun, so Kant considered his own philosophy as producing a kind of Copernican revolution in thought. Of course people will still continue to perceive the world pretty much in realist terms—just as we go about our daily lives without worrying about the fact that we live on a planet hurtling through space at many thousands of miles per hour— but even so, this realism has been exposed as an illusion. The illusion of realism is that it mistakes our experience of reality for reality itself. Realists like Dennett think of themselves as tough- minded empiricists, but they are not empirical enough to realize that all that is available to them are experiences and nothing beyond them. It is Kant, the transcendental idealist, who starts with experience and then proceeds from it by steps that reason can justify. By contrast, the empiricist begins with a presumption that is impossible to validate, and his whole philosophy is constructed on that dubious premise. The empiricist assumes without any evidence or proof that his experiences somehow give him a magical access to reality. So completely does he identify experience and r
eality that he cannot liberate himself from thinking of the two as one and the same. In equating experience and reality he is making a huge and unwarranted leap, but this breakdown of reason is not easy for him or us to recognize because our human minds have a built-in disposition toward illusion: the illusion that reality must be exactly the way we experience it. The irony is that many of the people who proceed in this irrational way think of themselves as following strictly along the pathways of reason. Their outlook can survive scrutiny only as long as they do not examine its foundations. To their credit, there are a few “brights” who take Kant seriously and attempt to answer his arguments. Kant cannot be right in saying that we have no access to reality, they say, because you and I and everyone else experience the same reality. When we are in a room, we see the same lamps and tables and books on the shelf. Obviously those must exist and we must have direct access to them; otherwise we would not all have the same perception of them. But Kant’s answer is that because we are all human beings, we have the same sensory equipment, and it operates in each of us in the same way. Therefore we all have the same experience, but the experience is all we have. Just because we have similar or even identical experiences does not mean that any of us has access to a reality that is beyond that experience. Biologist E. O. Wilson tries a different tack. Science, he says, is giving us new senses that are enabling us to go beyond our previous perceptual limitations. “With the aid of appropriate instruments we can now view the world with butterfly eyes.” With receivers and transformers and night-time photography we can experience the world in pretty much the same way as a bat. “Fish.” Wilson tells us, “communicate with one another by means of coded electrical bursts. Zoologists, using generators and detectors, can join the conversation.” If by this point you have grasped Kant’s reasoning, you will see right away that Wilson has done nothing to undermine it. Yes, we can use night-time photography, but we are still viewing the images with our human eyes. Yes, we can use generators and detectors, but we are still using our five senses in order to read, hear, and interpret what those instruments say. In other words, our human apparatus of perception conditions the entire field of our experiences, and this has always been so and will continue to be so as long as we are human. Future scientific discoveries cannot alter this limitation because those discoveries too will have to be made and experienced through the constrained perceptual apparatus we possess. Kant’s conclusion was that the problem of reason is, in its fullest dimension, insoluble. There are permanent and inescapable limits to human reason, and it is foolish to go on pretending otherwise. While this conclusion that our reason is confined within the borders of our experience, and that reality in itself in permanently screened off from us by our own sensory limitations, may seem to some to be a very outlandish idea, in fact it is at the very center of Western philosophy. In perhaps the most famous metaphor in Western thought, Plato likened human beings to people living in a cave, shut out from the light of the sun, seeing only shadows and mistaking them for reality. Plato regarded our perceptions as mere images of a deeper and higher reality, the so-called Platonic forms, that he located somewhere outside the realm of human experience. And Plato’s teacher, Socrates, regarded himself as the wisest man in Athens because he alone knew how little fie knew. For all his breathtaking originality, Kant is squarely in the mainstream of Western thought. No one who understands the central doctrines of any of the world’s leading religions should have any difficulty understanding Kant, because his philosophical vision is congruent with the teachings of Hinduism, Buddhism, Islam, Judaism, and Christianity. It is a shared doctrine of these religions that the empirical world we humans inhabit is not the only world there is. Ours is a world of appearances only, a transient world that is dependent on a higher, timeless reality. That reality is of a completely different order from anything that we know, it constitutes the only permanent reality there is, and it sustains our world and presents it to our senses. Chris-tianity teaches that while reason can point to the existence of this higher domain, this is where reason stops: it cannot on its own investigate or comprehend that domain. But one day, it is promised, when our earthly journey is over, we will know the higher realm and see things as they really are. Sociologist Peter Berger writes, “The religious impulse, the quest for meaning that transcends the restricted space of empirical existence in this world, has been a perennial feature of humanity.” Now Kant has given this religious conviction a completely modern and rational foundation. It is of the highest importance to recognize that Kant’s ideas, while they confirm 69
core elements of religious thought, are entirely secular. Kant has arrived at them on the basis of reason alone. He does not employ any religious vocabulary, nor does he rely on any kind of faith. But in showing the limits of reason, Kant said, he did “make room for faith.” Kant is our Virgil, taking us as far as reason can go. From here onward we need a different guide, but Kant has helped to clear the way for us to proceed. Kant’s accomplishment was to unmask the intellectual pretension of the Enlightenment: that reason and science are the only routes to reality and truth. This illusion is very much with us today, making Kant’s thought, for all its intellectual demands on us, supremely relevant. So the “brights” can do their strutting, but Kant has shown them as intellectually naked. And so, thanks to Kant, the tables have been turned. The atheist is now revealed as dogmatic and arrogant, and the religious believer emerges as modest and reasonable. While the atheist arrogantly persists in the delusion that his reason is fully capable of figuring out all that there is, the religious believer lives in the humble acknowledgment of the limits of human knowledge, knowing that there is a reality greater than, and beyond, that which our senses and minds can ever apprehend.