I can't find the original volume so I may have got the exact words wrong, but I recall one of those marvellous old Punch cartoons in which every last detail is painstakingly explained. A devoted mother is looking proudly on at a military parade as her son's platoon marches past: "There's my boy, he's the only one in step!" On The Guardian letters page of December 19th 2006, I initiated an exchange about Professor Andrew McIntosh of Leeds university, who has publicly stated that he believes the world is only 6,000 years old, and publicly stated that the theory of evolution violates the second law of thermodynamics. Both these beliefs place McIntosh out of step with his scientific colleagues, not just his platoon but the entire regiment — to paraphrase Evelyn Waugh, the whole ruddy division. Amazingly, McIntosh is Professor of Thermodynamics at Leeds, and, equally amazingly, a letter supporting him has now appeared from Professor Stuart Burgess, Head of the Department of Mechanical Engineering at Bristol University . Other letters to the Editor indicate that a distressing number of otherwise knowledgeable and intelligent people have little conception of the enormity of what is being said.

Science doesn't work by vote and it doesn't work by authority. It is possible that Burgess and McIntosh really are the only ones in step, and the whole scientific establishment is flat wrong. Indeed, I shall bias my discussion in their favour by continuing to use that word 'establishment' with all its pejorative overtones of fuddyduddy, stick-in-the-muddy authoritarianism. I like mavericks. I like free spirits who buck the trend and strike out on their own. They are not usually right, but on the rare occasions when they are, they are very right indeed: importantly so, and all power to them. Maybe Burgess and McIntosh are right and all the rest of us — biologists, geologists, archeologists, historians, chemists, physicists, cosmologists and, yes, thermodynamicists and respectable theologians, the vast majority of Nobel Prizewinners, Fellows of the Royal Society and of the National Academies of the world — are wrong. Not just slightly wrong but catastrophically, appallingly, devastatingly wrong. It is possible, and I am going to follow that possibility through to its logical conclusion. I shall not here defend the views held by the scientific establishment. I am among those who have done that elsewhere, in many books. My purpose in this article is only to convey the full magnitude of the error into which, if Burgess and McIntosh are right, the scientific establishment has fallen.

First, the age of the Earth. McIntosh thinks, on bliblical authority alone, that it is less than 10,000 years. We establishment fuddyduddies think, using mutually corroborating evidence from many sources including several different radioactive isotopes in the rocks, that it is about 4.6 billion years. I shall not say here why I think we are right and McIntosh wrong. Instead, I shall simply calculate the magnitude of the difference between the two estimates. We of the 'establishment' think the Earth is 460,000 times older than McIntosh's estimate. It is as though McIntosh estimated the height of a man as 6 feet and then accused the rest of us of believing that the same man was 460,000 times as tall, or 521 miles. Or, looking the other way, it is as though McIntosh looked at the establishment geographers' measurement of the distance from New York to San Francisco and claimed that the true distance from sea to shining sea was 460,000 times smaller, namely about ten yards. Maybe McIntosh is right and all the rest of us wrong. All I have done here is calculate how spectacularly wrong we would be, if McIntosh is right.

Turning now to the Second Law of Thermodynamics, this is a topic on which Andrew McIntosh, as Professor of Thermodynamics at Leeds, might be thought to speak with special authority. He is backed up by Stuart Burgess, Head of Bristol's Department of Mechanical Engineering, which is another subject in which thermodynamics is paramount and central. Both these men have stated their authoritative opinion that the theory of evolution violates the Second Law of Thermodynamics. Nothing violates the Second Law of Thermodynamics. The great astrophyisicist Sir Arthur Eddington put it with memorable irony. "If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation." It is not for nothing that C P Snow used familiarity with the Second Law as his litmus test of scientific literacy.

The Second Law states that, in a closed system without external energy fed in from outside, entropy always increases. Entropy is often said to mean disorder, but in some ways the word 'mixed-upness' (Willard Gibbs's coining) fits better. A familiar metaphor is that of a library. If the readers in a library always leave books lying around on the tables, or shove them back on the shelves at random, the library will become increasingly disordered. To remain in a state of order, it needs an energetic librarian, constantly working to put books back on their proper shelves, and constantly checking the shelves for misplaced volumes. It is not that libraries have a magnetic attraction or an urgent drive towards a particular goal state called disorder. It is simply that the number of states of a library that we would call disordered is much greater than the tiny minority of states that we would recognize as ordered. There are many more ways of being disordered than of being ordered. No work needs to be done to drive a library toward one of the many states that we call disordered. It will just happen, willy nilly, unless energetic work is done to prevent the otherwise inevitable slide downhill into disorder.

The Second Law recognizes a similar downhill slide towards disorder in any closed system such as the universe, which lacks a source of externally supplied energy. In a local region with externally supplied energy, on the other hand, we may see what look like reversals, but the stress must be on 'local' and 'externally supplied'. Life on Earth may evolve towards greater complexity and increased order, but this is only possible because of a massive transfusion of energy from the sun. To return to the library analogy, natural selection, the nonrandom survival of successful genes in gene pools, could be called the librarian of life. And the energy to power it comes ultimately from the sun. The overall trend of the thermodynamic river is still downhill. But a small tithe of the sun's energy is trapped by plants and used to power a trickle in the reverse direction. This reverse trickle is to be found not only in evolution but in the physiology of every individual organism, and in many chemical reactions. It is like a ram pump, which uses the energy of a flowing river to pump a small quantity of the water uphill.

Once again, it is not my purpose here to argue for the validity of the Second Law. It is undisputed. Nor is it my purpose to defend evolution against the charge of violating it. My purpose is again to convey the sheer magnitude of the error that Burgess and McIntosh are attributing to their hugely more numerous 'establishment' colleagues, who accept evolution and supply cogent arguments against the suggestion that it violates the Second Law. As with the age of the Earth, this is not some minor, recondite dispute among scientists. It is a monumental disagreement. One side or the other has got to be wrong, and not just slightly wrong but catastrophically, ignominiously, disastrously wrong. Evolutionists are accused of believing in a theory that violates the Second Law of Thermodynamics. If Burgess and McIntosh are right, almost all the scientists in the world should, in Eddington's words, 'collapse in deepest humiliation.' If they are right, evolution has to be ruled out, not because of some evidential problems or deficiencies as is common in science, but for a much more radical reason. Evolution, on their view, is completely and utterly ruled out for the same kind of reason as a patent inspector will reject a design for a perpetual motion machine without even looking at it. We earlier saw that McIntosh is, in effect, accusing the scientific establishment of believing that a man is 521 miles tall. Now we see that he also accuses us of believing something as absurd as that a river will run uphill. Maybe he is right on both counts, but the sheer magnitude of the error attributed to the rest of us should at least give him pause. When I say it is not a minor mistake we scientists are accused of, I am giving a whole new depth of meaning to the word understatement.


Richard Dawkins FRS is the Charles Simonyi Professor of the Public Understanding of Science at Oxford University. His books include The Selfish Gene, The Blind Watchmaker, Climbing Mount Improbable, The Ancestor's Tale and, most recently, The God Delusion.