Synopsis
Book by Davies Paul
Extrait
Chapter 1
Reason and Belief
Human beings have all sorts of beliefs. The way in which they arrive at them varies from reasoned argument to blind faith. Some beliefs are based on personal experience, others on education, and others on indoctrination. Many beliefs are no doubt innate: we are born with them as a result of evolutionary factors. Some beliefs we feel we can justify, others we hold because of "gut feelings."
Obviously many of our beliefs are wrong, either because they are incoherent, or because they conflict with other beliefs, or with the facts. Two and a half thousand years ago, in ancient Greece, the first systematic attempt was made to establish some sort of common grounds for belief. The Greek philosophers sought a means to formalize human reasoning by providing unassailable rules of logical deduction. By adhering to agreed procedures of rational argument, these philosophers hoped to remove the muddle, misunderstanding, and dispute that so characterize human affairs. The ultimate goal of this scheme was to arrive at a set of assumptions, or axioms, which all reasonable men and women would accept, and from which the resolution of all conflicts would flow.
It has to be said that this goal has never been attained, even if it were possible. The modern world is plagued by a greater diversity of beliefs than ever, many of them eccentric or even dangerous, and rational argument is regarded by a lot of ordinary people as pointless sophistry. Only in science, and especially mathematics, have the ideals of the Greek philosophers been upheld (and in philosophy itself, of course). When it comes to addressing the really deep issues of existence, such as the origin and meaning of the universe, the place of human beings in the world, and the structure and organization of nature, there is a strong temptation to retreat into unreasoned belief. Even scientists are not immune from this. Yet there is a long and respectable history of attempts to confront such issues by rational and dispassionate analysis. Just how far can reasoned argument take us? Can we really hope to answer the ultimate questions of existence through science and rational inquiry, or will we always encounter impenetrable mystery at some stage? And just what is human rationality anyway?
The Scientific Miracle
Throughout the ages all cultures have extolled the beauty, majesty, and ingenuity of the physical universe. It is only the modern scientific culture, however, that has made any systematic attempt to study the nature of the universe and our place within it. The success of the scientific method at unlocking the secrets of nature is so dazzling it can blind us to the greatest scientific miracle of all: science works. Scientists themselves normally take it for granted that we live in a rational, ordered cosmos subject to precise laws that can be uncovered by human reasoning. Yet why this should be so remains a tantalizing mystery. Why should human beings have the ability to discover and understand the principles on which the universe runs?
In recent years more and more scientists and philosophers have begun to study this puzzle. Is our success in explaining the world using science and mathematics just a lucky fluke, or is it inevitable that biological organisms that have emerged from the cosmic order should reflect that order in their cognitive capabilities? Is the spectacular progress of our science just an incidental quirk of history, or does it point to a deep and meaningful resonance between the human mind and the underlying organization of the natural world?
pardFour hundred years ago science came into conflict with religion because it seemed to threaten Mankind's cozy place within a purpose-built cosmos designed by God. The revolution begun by Copernicus and finished by Darwin had the effect of marginalizing, even trivializing, human beings. People were no longer cast at the center of the great scheme, but were relegated to an incidental and seemingly pointless role in an indifferent cosmic drama, like unscripted extras that have accidentally stumbled onto a vast movie set. This existentialist ethos -- that there is no significance in human life beyond what humans themselves invest in it -- has become the leitmotif of science. It is for this reason that ordinary people see science as threatening and debasing: it has alienated them from the universe in which they live.
In the chapters that follow I shall present a completely different view of science. Far from exposing human beings as incidental products of blind physical forces, science suggests that the existence of conscious organisms is a fundamental feature of the universe. We have been written into the laws of nature in a deep and, I believe, meaningful way. Nor do I regard science as an alienating activity. Far from it. Science is a noble and enriching quest that helps us to make sense of the world in an objective and methodical manner. It does not deny a meaning behind existence. On the contrary. As I have stressed, the fact that science Works, and works so well, points to something profoundly significant about the organization of the cosmos. Any attempt to understand the nature of reality and the place of human beings in the universe must proceed from a sound scientific base. Science is not, of course, the only scheme of thought to command our attention. Religion flourishes even in our so-called scientific age. But as Einstein once remarked, religion without science is lame.
The scientific quest is a journey into the unknown. Each advance brings new and unexpected discoveries, and challenges our minds with unusual and sometimes difficult concepts. But through it all runs the familiar thread of rationality and order. We shall see that this cosmic order is underpinned by definite mathematical laws that interweave each other to form a subtle and harmonious unity. The laws are possessed of an elegant simplicity, and have often commended themselves to scientists on grounds of beauty alone. Yet these same simple laws permit matter and energy to self-organize into an enormous variety of complex states, including those that have the quality of consciousness, and can in turn reflect upon the very cosmic order that has produced them.
Among the more ambitious goals of such reflection is the possibility that we might be able to formulate a "Theory of Everything" -- a complete description of the world in terms of a closed system of logical truths. The search for such a TOE has become something of a holy grail for physicists. And the idea is undoubtedly beguiling. After all, if the universe is a manifestation of rational order, then we might be able to deduce the nature of the world from "pure thought" alone, without the need for observation or experiment. Most scientists reject this philosophy utterly, of course, hailing the empirical route to knowledge as the only dependable path. But as we shall see, the demands of rationality and logic certainly do impose at least some restrictions on the sort of world that we can know. On the other hand, that same logical structure contains within itself its own paradoxical limitations that ensure we can never grasp the totality of existence from deduction alone.
History has thrown up many physical images for the underlying rational order of the world: the universe as a manifestation of perfect geometrical forms, as a living organism, as a vast clockwork mechanism, and, most recently, as a gigantic computer. All of these images capture some key aspect of reality, though each is incomplete on its own. We shall examine some of the latest thinking about these metaphors, and the nature of the mathematics that describes them. This will lead us to confront the questions: What is mathematics? And why does it work so well in describing the laws of nature? And where do these laws come from anyway? In many cases the ideas are easy to describe; sometimes they are rather technical and abstract. The reader is invited to share this scientific excursion into the unknown, in search of the ultimate basis of reality. Though the going gets rough here and there, and the destination remains shrouded in mystery, I hope that the journey itself will prove exhilarating.
Human Reason and Common Sense
It is often said that the factor which most distinguishes human beings from other animals is our power to reason. Many other animals seem to be aware of the physical world to a greater or lesser extent, and to respond to it, but humans claim more than mere awareness. We also possess some sort of understanding of the world, and of our place within it. We are capable of predicting events and of manipulating natural processes to our own ends, and although we are part of the natural world, we somehow distinguish between ourselves and the rest of the physical universe.
In primitive cultures, understanding of the world was limited to everyday affairs, such as the passage of the seasons, or the motion of a slingshot or an arrow. It was entirely pragmatic, and had no theoretical basis, except in magical terms. Today, in the age of science, our understanding has,vastly expanded, so that we need to divide knowledge up into distinct subjects -- astronomy, physics, chemistry, geology, psychology, and so on. This dramatic progress has come about almost entirely as a result of "the scientific method": experiment, observation, deduction, hypothesis, falsification. The details need not concern us here. What is important is that science demands rigorous standards of procedure and discussion that set reason over irrational belief.
The concept of human reasoning is itself a curious one. We are persuaded by "reasonable" arguments, and feel happiest with those that appeal to "common sense." Yet the processes of human thought are not God-given. They have their origin in the structure of the human brain, and the tasks it has evolved to perform. The operation of the brain, in turn, depends on the laws of physics and the nature of the physical world we inhabit. What we call common sense is the product of thought patterns deeply embedded in the human psyche, presumably because they confer certain advantages in dealing with everyday situations, like avoiding falling objects and hiding from predators. Some aspects of human thought will be fixed by the wiring of our brains, others inherited as "genetic software" from our ancestors of long ago.
The philosopher Immanuel Kant argued that not all our categories of thought derive from sensory experience of the world. He believed that some concepts are a priori, by which he meant that, although these concepts are not necessary truths in the strictly logical sense, nevertheless all thought would be impossible without them: they would be "necessary for thought." One example Kant gave was our intuitive understanding of three-dimensional space through the rules of Euclidean geometry. He supposed that we are born with this knowledge. Unfortunately, scientists have now discovered that Euclidean geometry is actually wrong! Today, scientists and philosophers generally suppose that even the most basic aspects of human thought must ultimately refer back to observations of the physical world. Probably the concepts that are most deeply etched in our psyche, the things that we find it hard to imagine could be otherwise -- such as "common sense" and human rationality -- are those that are genetically programmed at a very deep level in our brains.
It is interesting to speculate whether alien beings who evolved under very different circumstances would share our concept of common sense, or indeed any of our thought patterns. If, as some science-fiction writers have mused, life existed on the surface of a neutron star, one could not begin to guess how such beings would perceive and think about the world. It is possible that an alien's concept of rationality would differ from ours so greatly that this being would not be at all persuaded by what we would regard as a rational argument.
Does this mean that human reasoning is suspect? Are we being excessively chauvinistic or parochial in supposing that we can successfully apply the thought patterns of Homo sapiens to the great issues of existence? Not necessarily. Our mental processes have evolved as they have precisely because they reflect something of the nature of the physical world we inhabit. What is a surprise is that human reasoning is so successful in framing an understanding of those parts of the world our perceptions can't directly reach. It may be no surprise that human minds can deduce the laws of falling objects, because the brain has evolved to devise strategies for dodging them. But do we have any right to expect extensions of such reasoning to work when it comes to nuclear physics, or astrophysics, for example? The fact that it does work, and works "unreasonably" well, is one of the great mysteries of the universe that I shall be investigating in this book.
But now another issue presents itself. If human reasoning reflects something of the structure of the physical world, would it be true to say that the world is a manifestation of reason? We use the word "rational" to mean "in conformity with reason," so my question is whether, or to what extent, the world is rational. Science is founded on the hope that the world is rational in all its observable aspects. It is possible that there may be some facets of reality which lie beyond the power of human reasoning. This doesn't mean that these facets are necessarily irrational in the absolute sense. Denizens of neutron stars (or supercomputers) might understand things that we, by the very nature of our brains, cannot. So we have to be aware of the possibility that there may be some things with explanations that we could never grasp, and maybe others with no explanation at all.
In this book I shall take the optimistic view that human reasoning is generally reliable. It is a fact of life that people hold beliefs, especially in the field of religion, which might be regarded as irrational. That they are held irrationally doesn't mean they are wrong. Perhaps there is a route to knowledge (such as through mysticism or revelation) that bypasses or transcends human reason? As a scientist I would rather try to take human reasoning as far as it will go. In exploring the frontiers of reason and rationality we will certainly encounter mystery and uncertainty, and in all probability at some stage reasoning will fail us and have to be replaced either by irrational belief or frank agnosticism.
If the world is rational, at least in large measure, what is the origin of that rationality? It cannot arise solely in our own minds, because our minds merely reflect what is already there. Should we seek explanation in a rational Designer? Or can rationality "create itself" by the sheer force of its own "reasonableness"? Alternatively, could it be that on some "larger scale" the world is irrational, but that we find ourselves inhabiting an oasis of apparent rationality, because that is the only "place" where conscious, reasoning beings could find themselves? To explore these sorts of questions further, let us take a more careful look at the different types of reasoning.
Thoughts About Thought
Two sorts of reasoning serve us well, and it is important to keep a clear distinction between them. The first is called "deduction." This is based on the strict rules of logic. According to standard logic, certain statements, such as "A dog is a dog" and "Everything either is, or is not, a dog," are accepted as true, while others, like "A dog is not a dog," are deemed false. A deductive argument starts out with a set of assumptions called "premises." These are ...
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