The Attack on the Argument from Design
The Design Argument for the existence of God has been attacked on the ground that structure can arise in a purely natural and spontaneous way without any planning or any intervention by an intelligent being. In fact, at least three different ways are known by which structure can arise naturally: (1) pure chance, (2) the laws of nature, and (3) natural selection.
Let us return to William Paley wandering about his heath picking up stones. If the stones scattered about the heath are randomly shaped, then it is quite unlikely that on a brief walk Paley will find any interesting ones. However, if he examines a great number of stones he has a chance of finding one that is peculiarly shaped. He may find one that is very symmetric, or one that looks like it has some purpose. I imagine that most of us have come across a stone that bore an accidental resemblance to a primitive tool.
In other words, given enough chances complicated patterns are bound to appear accidentally. This is the old “monkey with a typewriter” idea. According to probability theory, if a monkey were to type randomly for an unlimited time, eventually it would accidentally type the play Hamlet, or indeed any other text. How long would it be before that monkey typed the play Hamlet? The answer is that the number of pages the monkey would have to type to have a chance of typing Hamlet is so huge, that just to write down that number would require a book longer than the play Hamlet itself. Even if we were only to wait for the monkey to accidentally type a particular fairly short sentence it would take an inconceivably long time. For example, in order for the monkey to have a reasonable chance of accidentally typing the words Mary had a little lamb, it would have to type about 1,000,000,000,000,000,000,000,000,000 pages.
In view of these large numbers, it seems implausible that any structure of significant complexity would arise entirely by chance. However, I shall return to this point later, because despite the seemingly impossible odds there is a way that it might happen.
Now, if Paley were to come across a stone that was cubical or rhombohedral in shape it would not be too surprising. Many crystals have those shapes, and there is a perfectly good explanation of how crystals form naturally. Under certain conditions, atoms or molecules do arrange themselves, without any help, into very regular arrays. This happens when water freezes, for example. When the temperature of water is above the freezing point, the water molecules move around in a random way. But when the temperature is lowered to the freezing point, they begin to line up rank upon rank in a hexagonal pattern. This happens automatically. Aimless molecular motions end up producing a highly ordered structure. There is no traffic cop directing this process; it is a natural consequence of the laws of physics.
Another example is the regular motion of the planets around the Sun. The orbits of most of the planets are very close to being circular. Moreover, these circles all lie almost in the same plane, so that the solar system looks like a giant pinwheel or platter. As we shall see later, this orderly arrangement and pattern of motion emerged in a natural way out of the chaotically swirling cloud of dust and gas which cooled and condensed to form the planets. Again, the orderliness of the final arrangement did not require any intervention in the process by an intelligent being; it required only the operation of the laws of physics.
The kinds of processes just mentioned, where the laws of physics lead in a fairly direct way to the formation of structure, produce only the kind that I called symmetric structure. The freezing of liquids and the gravitational condensation of dust clouds lead to elegant patterns but they do not lead to complex organisms. For a long time there was really no good idea to explain how organic structure could arise in a natural manner. Probably this was one reason why Macaulay, in the passage quoted in chapter 9, laid particular stress on biological structures, like flowers, leaves, and shells, as being evidence of a designer. However, very shortly after Macaulay wrote that passage Charles Darwin published his monumental work On the Origin of Species.
The significance of Darwin’s work was not simply that it challenged the scientific accuracy of the accounts given in the Book of Genesis. That is a relatively minor thing. We have already seen that even in ancient times there was a great deal of variation in how those accounts were interpreted, and many writers of high authority in the church read them in a very non-literal way. The deeper challenge posed by Darwin’s theory was the idea of “natural selection.” This idea showed for the first time how complex functional structures could have arisen by purely natural means, through chance rather than design. As a result, there are many who believe that Darwin’s theory has destroyed once and for all the Argument from Design for the existence of God. That is why the philosopher Daniel Dennett calls natural selection “Darwin’s Dangerous Idea,” and made that the title of one of his books.1 And it is why the biologist Richard Dawkins has said that Darwin, by giving us “design without design,” made it possible for the first time to be “an intellectually fulfilled atheist.”2 Darwin, he says, provided an answer to Paley’s famous watch argument.
If we think of the watch in Paley’s argument as standing for the organic structure of a living thing, then, says Dawkins, we now know who made that watch: it was not God or any other intelligent designer; rather, it was the very universe itself acting blindly according to chance and the laws of physics. The universe is “the Blind Watchmaker”—the title of Dawkins’s best-known book.3
If we look at a fish, for example, we observe that its fins, its streamlined shape, and many other features of its anatomy help it to swim better. It seems well “designed” for swimming. But that, according to Darwin, is not due to foresight on the part of any designer. No one looked ahead and, anticipating that a fish would swim, decided to incorporate these features into its design. Rather, it is thought that at some early time there existed aquatic creatures that were less sophisticated in structure and that were not such efficient swimmers. By a process of trial and error, various small changes in structure led the descendants of those creatures to be better and better adapted to this form of locomotion. Perhaps a creature with no fin had, due to random genetic mutations, offspring that had small fin-like protuberances. This novelty may have given those offspring a slight edge in the struggle for survival. Members of their species who had small fin-like protuberances consequently left more descendants on average than those who did not, and came to predominate. Over time, the same process of random mutation and natural selection led to creatures with larger and more functional fins.
Therefore, fins do indeed have a “purpose” in the sense of a natural function for which they are adapted, but they do not reveal a purpose in the sense of an intention that existed ahead of time in somebody’s mind.
Thus, as Dawkins admits, the bodies of living organisms do have characteristics—complexity and functionality—that one normally associates with things that have been designed. But in light of Darwin’s idea of natural selection we now realize, he says, that these structures arose in a completely different, haphazard way. He calls such objects, which appear to be designed, but really are not, “designoids.”4 Dawkins claims that living things, including human beings, are designoids. It was, he argues, due to the fact that people were familiar with designed objects, but did not understand the theoretical possibility of designoids, that they fell into the fallacy of the Design Argument for the existence of God. We shall return to these arguments in chapter 13.
While we are on the subject of biological structures, it should be mentioned that there is one huge question about life that natural selection does not seem able to answer, and that is how the first living thing originated. This is the so-called origin-of-life problem. It is generally believed by biologists that all living things on Earth are descended from a single original one-celled creature. How did that first creature evolve? It cannot have been by the ordinary Darwinian mechanism of natural selection, since for natural selection to operate there already has to be life—that is, self-reproducing organisms able to pass on their traits genetically.
The origin-of-life problem is made very hard by the fact that that first, “primitive” life-form was probably already enormously complicated. Partly in response to claims that vestiges of one-celled life had been discovered in Martian rocks, biologists have given some thought to the minimum requirements for a self-reproducing one-celled organism. It appears that it needs to have quite an elaborate structure, involving dozens of different proteins, a genetic code containing at least 250 genes, and many tens of thousands of bits of information.5 For chemicals to combine in random ways in a “primordial soup” to produce a strand of DNA or RNA containing such a huge amount of genetic information would be as hard as for a monkey to accidentally type an epic poem.
Decades of attempts to solve this problem have borne little fruit.6 Consequently, there are those who argue that none of the three ways of naturally explaining structure that we have discussed—pure chance, law, and natural selection—are capable of explaining the origin of life. They contend that this impossibility adds up to an irrefutable proof of divine intervention. However, this proof has a loophole. It is probably correct to say that natural selection and law are insufficient to explain the origin of life. But actually pure chance may be enough. The point is that the universe may well be infinitely large and have an infinite number of planets. This would be the case, for example, in the standard Big Bang cosmological model if the universe has an “open” geometry. (See chapter 7, in the section titled The Universe in the Standard Big Bang Model.) No matter how small the probability of life forming accidentally on a single planet, as long as that probability is finite, life is bound to form if there exist a truly infinite number of planets. Returning to the monkey-and-typewriter analogy: if there are an infinite number of monkeys typing, then some of them inevitably will be typing Hamlet. In fact, as remarkable as it sounds, it can be shown that if there are truly an infinite number of planets then somewhere there must exist a planet identical to ours in every particular, on which live species exactly like our own, and indeed on which lives a being who is genetically and in every other way biologically identical to you. Infinity is a very large number.
Are there an infinite number of planets? It is impossible for us to know by direct observation, because we cannot see what lies beyond our “horizon” of about 15 billion light-years. (See the section titled The Eternal Inflation Scenario.) But it is interesting that in order to explain the origin of life from inanimate matter in a way that does not invoke divine intervention it may be necessary to postulate an unobservable infinity of planets. Does this ring a bell? In chapter 7 we saw that in order to avoid a beginning of time, the materialist has to assume that before the Big Bang there was an infinite stretch of time about which (almost certainly) nothing can be known by direct observation. We shall see in later chapters other cases where the materialist, in order to avoid drawing unpalatable conclusions from scientific discoveries, has to postulate unobservable infinities of things. How ironic that, having renounced belief in God because God is not material or observable by sense or instrument, the atheist may be driven to postulate not one but an infinitude of unobservables in the material world itself!
In any event, we have identified three ways of explaining complicated structures naturally: (1) pure chance (combined, possibly, with the supposition of an infinite universe), (2) the laws of nature, and (3) natural selection. Does the possibility of such explanations fatally undermine the age-old Argument from Design? Has science, in this case at least, eroded the credibility of the religious worldview? It is to this question that I will now turn. The two versions of the Argument from Design that we distinguished between, the cosmic and the biological, raise somewhat different issues and should be discussed separately. I will begin with the Cosmic Design Argument and in particular with the question of whether the laws of nature can themselves be a substitute for God in explaining the order that is seen “in the heavens and on earth.”