“Mr. Derbyshire—Your review of Simon Singh’s book in the Feb. 28 issue of

National Review included a general defense of the integrity of scientists.

Singh, you say, ‘gives the reader a valuable lesson in the progress of

scientific inquiry, in the nature of scientific method and the means by

which controversies in science are resolved. A great deal of nonsense is

talked and written about this, particularly by anti-evolution propagandists.

Singh’s account shows plainly that the generality of scientists are neither

passionless Mister Spocks, weighing evidence with cold, flawless

objectivity, nor grim upholders of a pseudo-religious dogma determined to

defend crumbling theories to the last ditch.’

“Would you be as comfortable with that quote were ‘anti-evolution’ replaced

by ‘anti-global-warming’? I’m afraid that I can’t recall whether you have

written anything about Bjorn Lomborg, but National Review has certainly had

a lot to say about the scientific establishment’s defense of the

’pseudo-religious dogmas’ of environmentalism against Lomborg’s skepticism.

“You say that scientists are ‘reluctant to let go of the convictions of a

lifetime, but usually willing to do so when faced with convincing evidence.’

Do you believe that to be as true of environmental scientists as it is of

physicists? What about evolutionary biologists?”

Reply:

The key phrase there is “convincing evidence.” Broadly speaking, when

evidence is very sparse, the human side of scientists comes out, and there

is much grandstanding, politicking, and ego-tripping. So it was with the

Big Bang until the 1970s, when the weight of evidence began to make the

anti-Big-Bangers look silly. When evidence reaches a critical mass, science

at large swings behind the better theory. A few eccentrics like Hoyle might

hold out; but science **at large** knows the difference between a theory

that fits the evidence parsimoniously, and one that doesn’t. Not only does

it know it, in fact, it depends on that knowledge for its livelihood and

reputation! I don’t know any counterexamples to this rule. The problem,

again, is that when the evidence is scanty, pretty much anything can be made

to fit.

With global warming things are much worse than they were with Big Bang

because there are more political points to be made (Rich countries BAD!

Poor countries GOOD!) and more gummint money to be spent. The fundamental

problem is the same, though. The evidentiary database is just too sparse.

You can make any sort of case from it. The earth is a large object:

measuring its average temeperature is a tricky business. Trying to see

whether that temperature has changed across decades is an order of magnitude

harder. And then you have to try to figure out whether, if there *is*

change, it’s caused by human activity. (Followed, of course, by the

question: If there is change, and it is human-caused, DOES IT MATTER?)

Evolutionary biology presents a different case. The origin of species by

natural selection via mutated forms is the only theory we have. There isn’t

another one. (“God makes it happen!” isn’t a scientific theory, only a

metaphysical one.) There is no competition of theories here, of the type

Big Bang vs. Steady State, or Global Warming vs. No Global Warming (or

Man-Made Global Warming vs. Natural Global Warming). Nobody has an

alternative theory. This may be just a failure of imagination on the part

of biologists. Perhaps next week someone will come up with an alternative

theory for the origin of species that will make Natural Selection via

Mutations look silly. Until that happens, though, NSvM is the only game in

town. And it looks pretty good. We don’t have any observations that

contradict it (e.g. a species of winged insects arising in a single

generation from a species of un-winged ones). *And* the more we learn about

the actual mechanisms of morphology & inheritance, the better the theory

looks. Of course it might be all wrong — it’s just a theory; but at

present there is no reason to think it’s all wrong, and again, NO

ALTERNATIVE THEORY.