Doubts about Darwin
Sir: The letter from Mr Bethel] (23 June) on Darwinism was a typical piece of linguistic logic-chopping, written for the purpose of dumbfounding the tyros. Mr Bethel] labours under the illusion that because Darwin introduced 'Darwinism' and Popper Topperism', thereby they became custodians of the insights they propounded.
Because Darwin may have agreed that the 'survival of the fittest' was an apt sum mary of his own theory does not mean that it is. In fact, it is not. Natural selection is far too sophisticated a concept to be summarised in such a silly way.
Subsequently we are glibly assured that 'unfalsifiable theories are useless in science.' Mr Bettiell is unaware that the support Sir Karl can muster for his inflexible interpretation of his own theory is rapidly dwindling to a minority of two: himself and Mr Bethell. The fact that as yet inadequate evidence has been adduced does not mean that natural selection is not a scientific hypothesis.
Some applications of the theory of the natural selection of heritable advantageous variations are demonstratively true. The general significance of the theory is a matter of debate. It may be superseded, as was Newton's, by a superior theory. What grates on me and others about letters like Mr Be thel l's is not that selection is attacked but that there is a counter-theory motivating them, unstated but a good deal less rational. A. F. George 15 Finchdene Grove, Finchfield, Wolverhampton, West Midlands Sir: Mr Bethel] may be right in saying that no organism could be discovered that would disprove Darwin's theory of evolution by natural selection (23 June), but is quite wrong in supposing that this is the relevant test. It can only be disproved by observing evolutionary change.
If organic evolution is indeed caused by natural selection then it should be possible to show that whenever an evolutionary change takes place, it does so because of genetic differences between those individuals that successfully reproduce and those that fail. Such observations are admittedly few, but among the better known are the evolution of melanism as camouflage by moths in the industrial parts of England, insecticide resistance by mosquitoes and antibiotic resistance by bacteria. In each case organisms have evolved fast enough to show that a change in the environment has conferred a survival value on rare mutants which have consequently become commoner in the population with each generation.
A. W. Harvey 29 Earl's Court Square, London SW5
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