R. A . Fisher’s comment on Otmar von Verschuer in 1948: An Explanation.

Richard Dawkins 3
History Reclaimed
Written by History Reclaimed

Sir Ronald Fisher, geneticist and statistician, has been described by Richard Dawkins as the most important biologist since Charles Darwin. Yet in 2020 he was dishonoured by his own Cambridge college. In this article, his pupil and fellow geneticist Anthony Edwards explains the meaning of a sentence written in 1948 that has been used to shame Fisher.

In 2020, Caius College, Cambridge removed a memorial window it had erected in its Hall in 1989 to the great geneticist and statistician, and a former President (senior fellow) of the college, Sir Ronald Aylmer Fisher.[i] Like many geneticists and statisticians of the early twentieth century, Fisher was a eugenicist who believed that nations should make attempts to improve what was often called ‘the racial stock’ by deterring procreation by some groups and encouraging it among others. In this belief, he was not alone. It was very widely held across Cambridge where he was educated, where he taught, and where he held a college fellowship for many years. [ii]

When Fisher was the student chairman of the Cambridge University Eugenics Society, its treasurer was John Maynard Keynes, the great economist. Like the majority in the British eugenics movement, Fisher  – and Keynes also – believed in voluntary rather than compulsory sterilisation for those with severe learning difficulties, a position which was never endorsed or implemented by any British government. This is to be contrasted with beliefs and actions in Germany, Sweden and the United States, where compulsory sterilization was widely supported and practised between the World Wars.[iii]

Despite holding views that were very common among Edwardian and inter-war intellectuals, and despite his enormous contributions to science and mathematics – Fisher is the man who devised randomised testing which is used daily in thousands of procedures across the world – Fisher was shamed and his window removed. This defenestration, and the statement justifying it, were highly controversial both inside Caius and far beyond. [iv]

It is worth remarking that another of the windows erected in 1989 memorialises Sir James Chadwick, another fellow of Caius, but more importantly, the discoverer of the neutron and the leader of the Tube Alloys project during the Second World War. That was the code name given to the British team working on the atomic bomb whom Chadwick led to Los Alamos in 1943. Sadly, you won’t hear anything about that in the current film Oppenheimer. It’s worth remarking that an earlier generation might have opposed Chadwick’s window, but this generation of dons and students opposes Fisher’s. It is a marker of attitudinal change in British society.

The Fisher controversy (writing that reminds one of the much earlier and more famous ‘[Fritz] Fischer Controversy’ over the origins of the First World War)[v] split the fellowship of Caius College and raised wider questions about the relationship of science and politics. No one doubts Fisher’s scientific eminence; but he has been shamed because his views – perfectly common in his own era – no longer accord with opinion today. Once more the present takes revenge upon the past.

But in this case the problems go further because Caius College is effectively policing the views of its (former) members.[vi] For many people, the political views of a scientist or scholar are of no account as long as they remain matters of personal conviction and do not distort their scientific or scholarly work. What Fisher thought – which was in no way extreme when compared to the rest of his generation – is of little consequence when considering the eminence of his scientific contributions. A liberal society – and a genuinely liberal college society, at that – should demonstrate its liberal attitudes by allowing freedom of thought and celebrating the achievements of people with whom it may disagree.

Sadly, this is not how many fellows of Caius reacted in 2020 and subsequently. To judge and convict academics on the basis of their personal beliefs is a very slippery slope. Should we dishonour Newton because he was an alchemist or Einstein because he was a zionist? Or should the portrait of a previous Master of Caius College, Joseph Needham, biologist and historian of science, also be taken down from its place in the college Hall because he was a supporter of Mao Zedong and the Chinese Communist regime? If we start a scientific purge on entirely non-scientific grounds, where might it end?

In the debates over Fisher’s ‘guilt’ for holding such opinions, one particular sentence he wrote was used against him. He wrote it in a reference for a German geneticist, Otmar von Verschuer, in 1948 – after the Second World War therefore, and thus after the Holocaust and the preceding Nazi campaign of the 1930s in which hundreds of thousands of German citizens with learning difficulties were legally euthanised by the Third Reich.[vii] The sentence was seized upon by proponents of the shaming of Fisher in 2020, raising another issue in the process of public humiliation: just how much weight should be placed on single or occasional remarks, however miscast or ill-conceived, when set against a lifetime of intellectual or political achievement? The technique is used all the time in the denigration of great figures like Gladstone and Churchill.

In the essay below, Professor A. W. F. Edwards, a long-time fellow of Caius and a pupil of Fisher’s, examines the offending sentence in the context of its time and of the genetic knowledge and terminology then current.

Lawrence Goldman

Richard Dawkins 1

On 19 November 1948 Ronald Aylmer Fisher responded to a request from Professor Karl Wezler, the Dean of the Medical Faculty of the University of Frankfurt, for an opinion of Otmar Freiherr von Verschuer, a German medical geneticist. Attention has focussed on a

particular sentence of Fisher’s reply:

In spite of their prejudices I have no doubt also that the [Nazi] Party sincerely wished to benefit the German racial stock, especially by the elimination of manifest defectives, such as those deficient mentally, and I do not doubt that von Verschuer gave, as I should have done, his support to such a movement.

Historians have interpreted this as meaning that Fisher (and, in his opinion, von

Verschuer) supported the elimination of defectives in the current population. This is incorrect, and in the case of Fisher, unthinkable, overlooking the sense that he is writing about benefit to ‘the German racial stock’ of the distant future by the gradual and voluntary elimination of a defective gene.

Fisher’s letter was first published by Sheila Faith Weiss in 2010, who remarked that it was an ‘admittedly surprising assessment’ and ‘almost unbelievably positive’, but she did not attempt an interpretation.[viii] Neither have subsequent historians, preferring not to seek advice about Fisher’s meaning. The correct interpretation requires a  knowledge of human genetics and of its early language.

First we note that by ‘manifest defectives’ Fisher means sufferers from diseases produced by recessive mutations which, as we shall see, are also described as defective. ‘Manifest’ (‘having evident signs of’ – Shorter Oxford English Dictionary) is a favourite word of Fisher’s and here means conditions thought to be caused by single recessive mutations occurring in homozygous form.

Fisher’s use of such words in human genetics may be exemplified by his 1924 paper ‘The elimination of mental defect’ in which he reinterpreted some numerical results in R. C. Punnett’s 1917 paper ‘Eliminating feeblemindedness’. Fisher was careful to write ‘There is a considerable body of pedigree evidence indicating the existence of a single mendelian factor which, in its recessive phase, is capable alone of producing feebleness of mind’. Nowadays we know of many such examples, and Fisher was guarding himself against the overzealous interpretation of pedigrees by some of his contemporaries. His paper was a theoretical discussion of the rate at which the proportion of such cases would be reduced, generation by generation, by the segregation or voluntary sterilization of those manifesting the condition.

The following extract from the first chapter of The Genetical Theory of Natural Selection (Fisher, 1958 edn.), ‘The nature of inheritance’, gives further indications of his meaning:

Nor is the position apparently different with man and his domesticated animals and plants; as may be judged from the frequency with which striking recessive defects, producing, for example, albinism, deaf-mutism, and feebleness of mind in man, must have occurred in the comparatively recent past, as mutations . . . In addition to the defective mutations, which by their conspicuousness attract attention, we may reasonably suppose that other less obvious mutations are occurring which, at least in certain surroundings, or in certain genetic combinations, might prove themselves to be beneficial. It would be unreasonable, however, to assume that such mutations appear individually with a frequency much greater than that which is observed in the manifest defects.

The clarity of meaning is reinforced by the fact that the phrase ‘producing, for example, albinism…’ in this 1958 edition replaced ‘such as’ in the first edition published in 1930. Fisher had noticed that albinism, etc., are of course not mutations but the results of mutations.

It follows that the ‘manifest defectives’ in Fisher’s letter to Wezler are those who suffer from the conditions listed by Fisher caused by recessive single-gene mutations.

Richard Dawkins 2

‘Feebleness of mind’ and ‘deficient mentally’ were typical descriptions in use at the time. Naturally, in those pioneering days of human genetics in which Fisher was one of the foremost participants, there was not a clear understanding of which conditions were the result of single Mendelian mutations, whether of the recessive or the dominant type. But this did not preclude discussion of the possibilities of alleviating the load of such mutations in future populations (for example in ‘the German racial stock’).

Such policies would require, it was contended, a reduction in the fertility of those who suffered the genetic condition. Much discussion surrounded how this might be encouraged. Many in England were in favour of voluntary sterilisation. In 1932 Fisher had written ‘anything so big as eugenic aims must be controlled by the personal choice of individuals acquainted with their own individual needs and circumstances’. (He might almost have been describing modern genetic counselling.) He and the Eugenics Society opposed compulsory sterilisation. In the United States compulsory sterilization was legalised in many states, and with scant regard for certainty about the genetic basis of the condition. The methods in von Verschuer’s Nazi Germany need not be here described. To associate the name of Fisher with them by a misunderstanding of the principles and history of human genetics is a travesty of justice.


A.W. F. Edwards Cambridge, February 2024.



[i] https://www.theguardian.com/education/2020/jun/27/cambridge-gonville-caius-college-eugenicist-window-ronald-fisher

[ii] A. W. F. Edwards. ‘Cancelled by his College’, The Critic, March 2021. https://thecritic.co.uk/issues/march-2021/cancelled-by-his-college/

[iii] Dorothy Porter, ‘Eugenics and the Sterilization Debate in Sweden and Britain before World War II’, Scandinavian Journal of History, 24, 2, 145-62.

[iv] Lawrence Goldman, Victorians and Numbers. Statistics and Society in Nineteenth Century Britain (OUP, 2022), vii-viii.

[v] Fritz Fischer, Griff nach der Weltmacht: Die Kriegszielpolitik des kaiserlichen Deutschland 1914–1918. English translation published as Germany’s Aims in the First World War (1961)

[vi] Richard Evans, ‘R. A. Fisher and the Science of Hatred’, New Statesman, 28 July 2020.

[vii] Henry Friedlander, The Origins of Nazi Genocide: From Euthanasia to the Final Solution (Chapel Hill, N.C., 1995)

[viii] Weiss, Sheila Faith (2010). “After the Fall: Political Whitewashing, Professional Posturing, and Personal Refashioning in the Postwar Career of Otmar Freiherr von Verschuer”. Isis101 (4): 745.

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History Reclaimed

History Reclaimed