| EBON MUSINGS: THE EVOLUTION PAGES | ON EVOLUTION |
In his 1983 book The Intelligent Universe, astronomer Fred Hoyle wrote the following infamous passage:
"A junkyard contains all the bits and pieces of a Boeing 747, dismembered and in disarray. A whirlwind happens to blow through the yard. What is the chance that after its passage a fully assembled 747, ready to fly, will be found standing there? So small as to be negligible, even if a tornado were to blow through enough junkyards to fill the whole Universe." (p.19)
Though Hoyle actually intended this as an argument against abiogenesis, the creationists have since assimilated it and used it against evolution. In creationist literature, this argument has mutated into a diversity of forms: setting off an explosion in a print shop to produce a dictionary, disassembling a watch and shaking up the pieces in a box to reassemble it, and so on, building a bicycle by applying a blowtorch to a pile of bicycle parts, and so on. No matter what form the analogy takes, however, creationists have promoted it as a common-sense proof of the impossibility of evolution producing complex, highly ordered forms. There is even a creationist book titled Tornado in a Junkyard.
This essay will show that this analogy is not an accurate representation of how evolution (or, for that matter, abiogenesis) works. In fact, it is a straw man, a ridiculous caricature that bears no resemblance to what the theory actually says. However, it is first helpful to establish a few things about the credentials of its author. Fred Hoyle was an astronomer, and whatever the validity of his professional opinions on astronomy, he was not trained in biology, paleontology, genetics, or any other field having to do with evolution. He was no more qualified to make pronouncements about evolution than any layman, and indeed his comments demonstrate a profound misunderstanding of the theory. Nevertheless, whatever he was, he was certainly not a creationist.
"The creationist is a sham religious person who, curiously, has no true sense of religion. In the language of religion, it is the facts we observe in the world around us that must be seen to constitute the words of God. Documents, whether the Bible, Qur'an or those writings that held such force for Velikovsky, are only the words of men. To prefer the words of men to those of God is what one can mean by blasphemy. This, we think, is the instinctive point of view of most scientists who, curiously again, have a deeper understanding of the real nature of religion than have the many who delude themselves into a frenzied belief in the words, often the meaningless words, of men. Indeed, the lesser the meaning, the greater the frenzy, in something like inverse proportion."
--Fred Hoyle and Chandra Wickramasinghe, Our Place in the Cosmos (1993), p.14
"We are inescapably the result of a long heritage of learning, adaptation, mutation and evolution, the product of a history which predates our birth as a biological species and stretches back over many thousand millennia.... Going further back, we share a common ancestry with our fellow primates; and going still further back, we share a common ancestry with all other living creatures and plants down to the simplest microbe. The further back we go, the greater the difference from external appearances and behavior patterns which we observe today.... Darwin's theory, which is now accepted without dissent, is the cornerstone of modern biology. Our own links with the simplest forms of microbial life are well-nigh proven."
--Fred Hoyle and Chandra Wickramasinghe, Lifecloud: The Origin of Life in the Universe (1978), p.15-16
We turn now to the tornado in the junkyard. This analogy says nothing about the validity of evolution, or for that matter abiogenesis, because it fails to represent them in four crucial ways.
The first point is the most important. The tornado in the junkyard is an example of an intricate, complex and highly organized form being produced by nothing more than random chance. But evolution is not chance. (See this article for more on this.) Rather, it operates according to a fixed law - the law of natural selection - which favors some assemblages over others; it preferentially selects for those adaptations which improve fitness and selects against those that do not. The tornado, by contrast, slams parts together and tears them apart with no preference whatsoever, thus completely failing to represent natural selection, the central force which drives evolution. To more accurately represent evolution, one would have to grant the tornado some power to recognize assemblages of parts which could serve as part of a 747 and prevent it from tearing them apart.
Second, the tornado analogy is an example of single-step selection - in one step, it goes from a random pile of parts to a fully assembled airliner. This is completely unlike evolution, which operates according to a process of cumulative selection - complex results that are built up gradually, in a repetitive process guided at each step by selective forces. To more accurately represent evolution, the tornado could be sent through the junkyard not once, but thousands or millions of times, at each step preserving chance assemblages of parts that could make up a jumbo jet.
Third, in relation to the point above, the tornado in the junkyard is an example of saltation - a sudden leap in which the end product is completely different from the beginning product. Evolution does not work this way; birds do not hatch out of dinosaur eggs and monkeys do not give birth to humans. Rather, species grow different over time through a process of slow change in which each new creature is only slightly different from its ancestor. Evolution forms a gradually shading continuum in which any two steps are almost identical, though the creatures at the beginning and end of the continuum may be very different indeed. If we sent a tornado through a junkyard once, we would not expect to see a complete airplane; but if we repeated the process thousands or millions of times, at each step preserving useful assemblages, we might see a jumbo jet gradually taking shape out of slowly accreting collections of parts. The idea is the same with living things. We do not see complex new creatures appearing suddenly in the fossil record; rather, we see them gradually forming by a process of modification from a line of increasingly dissimilar ancestors.
Finally, the tornado analogy fails to represent evolution in one more significant way: it has a target specified ahead of time. Evolution does not. Natural selection is not a forward-looking process; it cannot select for what may become useful in the future, only what is immediately useful in the present. To more accurately represent evolution, we might add the additional stipulation that the tornado be allowed to assemble, not just a jumbo jet, but any functional piece of machinery.
A tornado racing through a junkyard hundreds of thousands of times, at each step somehow preserving rather than tearing apart functional assemblages of parts, with the aim of ultimately producing some sort of working machine, be it a 747, a station wagon or a personal computer - this is still not a very good analogy to describe evolution, but it is far better than the implausible caricature of random, single-step saltation with a predetermined target the creationists put forth. This analogy completely fails to represent evolution in every significant way.
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