Ronald Fisher

R. A. Fisher

Sir Ronald Fisher (17 February 189029 July 1962) was an evolutionary biologist, geneticist and statistician. He was the father-in-law of George Box.



  • There is, then, in this analysis of variance no indication of any other than innate and heritable factors at work. (Coining of the phrase ‘analysis of variance’.)
    • The causes of human variability. Eugenics Review 10, 213-220, 1918.
  • (Coining the phrase ‘test of significance’): Critical tests of this kind may be called tests of significance, and when such tests are available we may discover whether a second sample is or is not significantly different from the first.
    • Statistical Methods for Research Workers, Edinburgh: Oliver and Boyd, 1925, p.43.
  • Fairly large print is a real antidote to stiff reading.
    • 31 May 1929, in a letter to K.Sisam, Oxford University Press. Printed in Natural Selection, Heredity, and Eugenics, p.20, ed. J.H.Bennett, Oxford: Clarendon Press, 1983.


  • I believe that no one who is familiar, either with mathematical advances in other fields, or with the range of special biological conditions to be considered, would ever conceive that everything could be summed up in a single mathematical formula, however complex.
    • The evolutionary modification of genetic phenomena. Proceedings of the 6th International Congress of Genetics 1, 165-72, 1932.
  • However, perhaps the main point is that you are under no obligation to analyse variance into its parts if it does not come apart easily, and its unwillingness to do so naturally indicates that one’s line of approach is not very fruitful.
    • 25 February 1933, in a letter to L. Hogben. Printed in Natural Selection, Heredity, and Eugenics, J.H.Bennett, Oxford: Clarendon Press, 1983, p.218.
  • The analysis of variance is not a mathematical theorem, but rather a convenient method of arranging the arithmetic.
    • Discussion to ‘Statistics in agricultural research’ by J.Wishart, Journal of the Royal Statistical Society, Supplement, 1, 26-61, 1934.
  • (Coining phrase "null hypothesis") In relation to any experiment we may speak of this hypothesis as the “null hypothesis,” and it should be noted that the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation. Every experiment may be said to exist only in order to give the facts a chance of disproving the null hypothesis.
    • The Design of Experiments, Edinburgh: Oliver and Boyd, 1935, p.18
  • In scientific subjects, the natural remedy for dogmatism has been found in research. By temperament and training, the research worker is the antithesis of the pundit. What he is actively and constantly aware of is his ignorance, not his knowledge; the insufficiency of his concepts, of the terms and phrases in which he tries to excogitate his problems: not their final and exhaustive sufficiency. He is, therefore, usually only a good teacher for the few who wish to use their mind as a workshop, rather than a warehouse.*
    • Eugenics, academic and practical. Eugenics Review, 27, 95-100, 1935.
    • The original has ‘to store it as’ inserted before the final words ‘a warehouse’, likely a mistake left from an earlier draft.
  • Apart from sex linkage, we know almost nothing at present of linkage in man. Yet it is certain that every defect determined by a single factor must be located in one or other of twenty-three [sic] linkage groups. Each defect must therefore be linked in inheritance with numerous other observable traits, and with some of them is probably linked closely. The search for such linkage will certainly be lengthy, and at first, disappointing.
    • Eugenics, academic and practical. Eugenics Review, 27, 95-100, 1935
  • The academic mind, as we know, is sometimes capable of assuming an aggressive attitude. The official mind, on the contrary, is and has to be, expert in the art of self-defence.
    • Presidential Address to the First Indian Statistical Congress, 1938. Sankhya 4, 14-17.
  • To consult the statistician after an experiment is finished is often merely to ask him to conduct a post mortem examination. He can perhaps say what the experiment died of.
    • Presidential Address to the First Indian Statistical Congress, 1938. Sankhya 4, 14-17. ([1])


  • After all, it is a common weakness of young authors to put too much into their papers.
    • Contributions to Mathematical Statistics, New York: Wiley, 1950, p.10.308a.
  • ... the so-called co-efficient of heritability, which I regard as one of those unfortunate short-cuts, which have often emerged in biometry for lack of a more thorough analysis of the data.
    • British Agricultural Bulletin 4, 217–218, 1951.
  • Natural selection is a mechanism for generating an exceedingly high degree of improbability.
    • Reported by J. S. Huxley in Evolution in Action, London: Chatto and Windus, 1953.
  • was Darwin’s chief contribution, not only to Biology but to the whole of natural science, to have brought to light a process by which contingencies a priori improbable, are given, in the process of time, an increasing probability, until it is their non-occurrence rather than their occurrence which becomes highly improbable. ... Let the reader ... attempt to calculate the prior probability that a hundred generations of his ancestry in the direct male line should each have left at least one son. The odds against such a contingency as it would have appeared to his hundredth ancestor (about the time of King Solomon) would require for their expression forty- four figures of the decimal notation; yet this improbable event has certainly happened.
    • Retrospect of criticisms of the theory of natural selection. In Evolution as a Process, eds. J.S.Huxley, A.C.Hardy and E.B.Ford, London: Allen and Unwin, 1954.
  • Faith Is Not Credulity.
    • Subtitle to Science and Christianity, Friend 113, 995–996, 1955.
    • (in full: ‘Christian children should ... be taught that faith does not mean credulity; but is a quality, very like courage, which makes one hold fast to that which is good, ... .)
  • ... the best causes tend to attract to their support the worst arguments, which seems to be equally true in the intellectual and in the moral sense.
    • Statistical Methods and Scientific Inference, Edinburgh: Oliver and Boyd, 1956, p.31.
  • More attention to the History of Science is needed, as much by scientists as by historians, and especially by biologists, and this should mean a deliberate attempt to understand the thoughts of the great masters of the past, to see in what circumstances or intellectual milieu their ideas were formed, where they took the wrong turning or stopped short on the right track.
    • Natural selection from the genetical standpoint. Australian Journal of Science 22, 16-17, 1959.

Since 1960sEdit

  • The million, million, million ... to one chance happens once in a million, million, million ... times no matter how surprised we may be that it results in us.
    • Quoted by K.Mather, Heredity 30, 89–91, 1973.

The Genetical Theory of Natural Selection (1930)Edit

  • Natural Selection is not evolution.
    • Preface, opening sentence, p. vii
  • No practical biologist interested in sexual reproduction would be led to work out the detailed consequences experienced by organisms having three or more sexes; yet what else should he do if he wishes to understand why the sexes are, in fact, always two?
    • Preface, p. ix
  • No efforts of mine could avail to make the book easy reading.
    • Preface, p. x
  • We may consequently state the fundamental theorem of Natural Selection in the form : The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.
    • Defining the fundamental theorem of natural selection, Ch. 2, p. 35
  • Professor Eddington has recently remarked that 'The law that entropy always increases — the second law of thermodynamics — holds, I think, the supreme position among the laws of nature'. It is not a little instructive that so similar a law [the fundamental theorem of natural selection] should hold the supreme position among the biological sciences.
    • On the fundamental theorem of natural selection, Ch. 2, p. 36
  • [We are now] in a position to judge of the validity of the objection which has been made, that the principle of Natural Selection depends on a succession of favourable chances. The objection is more in the nature of an innuendo than of a criticism, for it depends for its force upon the ambiguity of the word chance, in its popular uses. The income derived from a Casino by its proprietor may, in one sense, be said to depend upon a succession of favourable chances, although the phrase contains a suggestion of improbability more appropriate to the hopes of the patrons of his establishment. It is easy without any very profound logical analysis to perceive the difference between a succession of favourable deviations from the laws of chance, and on the other hand, the continuous and cumulative action of these laws. It is on the latter that the principle of Natural Selection relies.
    • On the objection (still often made by creationists) that the theory of evolution predicts evolution occurs "only by chance", Ch. 2, p. 37
  • In organisms of all kinds the young are launched upon their careers endowed with a certain amount of biological capital derived from their parents. This varies enormously in amount in different species, but, in all, there has been, before the offspring is able to lead an independent existence, a certain expenditure of nutriment in addition, almost universally, to some expenditure of time or activity, which the parents are induced by their instincts to make for the advantage of their young. Let us consider the reproductive value of these offspring at the moment when this parental expenditure on their behalf has just ceased. If we consider the aggregate of an entire generation of such offspring it is clear that the total reproductive value of the males in this group is exactly equal to the total value of all the females, because each sex must supply half the ancestry of all future generations of the species. From this it follows that the sex ratio will so adjust itself, under the influence of Natural Selection, that the total parental expenditure incurred in respect of children of each sex, shall be equal; for if this were not so and the total expenditure incurred in producing males, for instance, were less than the total expenditure incurred in producing females, then since the total reproductive value of the males is equal to that of the females, it would follow that those parents, the innate tendencies of which caused them to produce males in excess, would, for the same expenditure, produce a greater amount of reproductive value; and in consequence would be the progenitors of a larger fraction of future generations than would parents having a congenital bias towards the production of females. Selection would thus raise the sex-ratio until the expenditure upon males became equal to that upon females.

About Ronald FisherEdit

  • He has made contributions to many areas of science; among them are agronomy, anthropology, astronomy, bacteriology, botany, economics, forestry, meteorology, psychology, public health, and-above all-genetics, in which he is recognized as one of the leaders. Out of this varied scientific research and his skill in mathematics, he has evolved systematic principles for the interpretation of empirical data; and he has founded a science of experimental design. On the foundations he has laid down, there has been erected a structure of statistical techniques that are used whenever men attempt to learn about nature from experiment and observation.
    • W. Allen Wallis (1952) at the University of Chicago while honoring Fisher with the Honorary degree of Doctor of Science; cited in: George E. P. Box (1976) "Science and Statistics" Journal of the American Statistical Association, Vol. 71, No. 356. (Dec., 1976), pp. 791-799.
  • A book that I rate only second in importance in evolution theory to Darwin's Origin (this as joined with its supplement Of Man), and also rate as undoubtedly one of the greatest books of the twentieth century
    • W.D. Hamilton, on the cover of the Variorum Edition of The Genetical Theory of Natural Selection (1999)
  • This is perhaps the most important book on evolutionary genetics ever written"
    • Laurence Cook, on The Genetical Theory of Natural Selection [2]

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Last modified on 14 April 2014, at 17:11