The difference between belief and scientific theory

Letters in The Guardian, Tuesday March 19, 2002

(1) From Christopher Young, Sheffield

Please will somebody explain to . . . all the . . . confuseniks what "theory" means in the context of science. It does not mean "hypothesis" but the body of methodological tools and data which provide a context for scientific investigation.

Evolution is a fact. So are mathematical sets, which are studied using set theory. The context for studying the facts of evolution is evolutionary theory. The fact that evolutionists refer to the theory of evolution no more means that the fact of evolution is in question than the fact that mathematicians talk about set theory casts doubt on the fact that the next number after one, two, three is four.

(2) From Dr David Harper, Cambridge

Evolution by natural selection is a fact, as modern medicine knows to its cost. Bacteria and parasites have grown resistant to the antibiotics and drugs that were developed in the latter half of the 20th century, and they have done so by pure Darwinian natural selection.

No longer is penicillin a "wonder drug", since natural selection has favoured those bacteria which - by chance - have the genetic means to resist it. If only one in a million bacteria contains the genes for antibiotic resistance, then it will survive and multiply when all around it are killed. Then a new population of bacteria arises, which all have the antibiotic resistance gene. Thus a new type of bacterium is born. Five hundred years ago, this might have been explained by appealing to supernatural forces. Science provides an explanation that is far simpler, supremely elegant and not subject to the impulsive whims of the gods.

(3) From Graham Cox, High Wycombe, Bucks

Evolution is observable and testable, and as such is true science. It's true that for large species such as ourselves, evolutionary changes occur on too extended a timescale to be easily observed and measured, but for much simpler species, this is far from being the case. The rise of antibiotic-resistant bacteria in the past 20 years is a directly observable consequence of evolution; there are countless other examples.

Evolution underpins and informs modern biology, medicine and biotechnology. It is shameful that people still have such a poor understanding of such an important science, and more shameful that our schools are still teaching hocus-pocus instead of correcting this glaring omission in our grasp of the world. We all need to wise up fast.

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