Peter Medawar Quotations

Today the world changes so quickly that in growing up we take leave not just of youth but of the world we were young in.

I cannot give any scientist of any age better advice than this: the intensity of a conviction that a hypothesis is true has no bearing over whether it is true or not.

The human mind treats a new idea the way the body treats a strange protein; it rejects it.

If politics is the art of the possible, research is surely the art of the soluble. Both are immensely practical-minded affairs.

To abdicate from the rule of reason and substitute for it an authentication of belief by the intentness and degree of conviction with which we hold it can be perilous and destructive. Religious beliefs give a spurious spiritual dimension to tribal enmities.

It is naïve to suppose that the acceptance of evolution theory depends upon the evidence of a number of so-called "proofs"; it depends rather upon the fact that the evolutionary theory permeates and supports every branch of biological science, much as the notion of the roundness of the earth underlies all geodesy and all cosmological theories on which the shape of the earth has a bearing. Thus antievolutionism is of the same stature as flat-earthism.

Heredity proposes and development disposes.

The case I shall find evidence for is that when literature arrives, it expels science.

I once spoke to a human geneticist who declared that the notion of intelligence was quite meaningless, so I tried calling him unintelligent. He was annoyed, and it did not appease him when I went on to ask how he came to attach such a clear meaning to the notion of lack of intelligence. We never spoke again.

[A certain class of explanations in science are] analgesics that dull the ache of incomprehension without removing the cause.

Twice in my life I have spent two weary and scientifically profitless years seeking evidence to corroborate dearly loved hypotheses that later proved to be groundless; times such as these are hard for scientists-days of leaden gray skies bringing with them a miserable sense of oppression and inadequacy.

The fact that scientists do not consciously practice a formal methodology is very poor evidence that no such methodology exists. It could be said-has been said-that there is a distinctive methodology of science which scientists practice unwittingly, like the chap in Moliere who found that all his life, unknowingly, he had been speaking prose.

If a person is A) poorly, B) receives treatment intended to make him better, and C) gets better, then no power of reasoning known to medical science can convince him that it may not have been the treatment that restored his health.

No scientist is admired for failing in the attempt to solve problems that lie beyond his competence. ... Good scientists study the most important problems they think they can solve. It is, after all, their professional business to solve problems, not merely to grapple with them.

I regret my disbelief in God.

It is high time that laymen abandoned the misleading belief that scientific enquiry is a cold dispassionate enterprise, bleached of imaginative qualities, and that a scientist is a man who turns the handle of discovery; for at every level of endeavour scientific research is a passionate undertaking and the Promotion of Natural Knowledge depends above all on a sortee into what can be imagined but is not yet known.

The intensity of a conviction that a hypothesis is true has no bearing on whether it is true or false. The importance of the strength of our conviction is only to provide a proportionately strong incentive to find out if the hypothesis will stand up to critical evaluation.

In all sensation we pick and choose, interpret, seek and impose order, and devise and test hypotheses about what we witness. Sense data are taken, not merely given: we learn to perceive.... The teacher has forgotten, and the student himself will soon forget, that what he sees conveys no information until he knows beforehand the kind of thing he is expected to see.

I reckon that for all the use it has been to science about four-fifths of my time has been wasted, and I believe this to be the common lot of people who are not merely playing follow-my-leader in research.

Innocent, unbiased observation is a myth.

Science is the art of the solvable.

An experiment not worth doing is not worth doing well.

Scientists are entitled to be proud of their accomplishments, and what accomplishments can they call 'theirs' except the things they have done or thought of first? People who criticize scientists for wanting to enjoy the satisfaction of intellectual ownership are confusing possessiveness with pride of possession. Meanness, secretiveness and, sharp practice are as much despised by scientists as by other decent people in the world of ordinary everyday affairs; nor, in my experience, is generosity less common among them, or less highly esteemed.

It is a truism to say that a good experiment is precisely that which spares us the exertion of thinking: the better it is, the less we have to worry about its interpretation, about what it really means.

Freudian psychoanalytical theory is a mythology that answers pretty well to Levi-Strauss's descriptions. It brings some kind of order into incoherence; it, too, hangs together, makes sense, leaves no loose ends, and is never (but never) at a loss for explanation. In a state of bewilderment it may therefore bring comfort and relief.... give its subject a new and deeper understanding of his own condition and of the nature of his relationship to his fellow men. A mythical structure will be built up around him which makes sense and is believable-in, regardless of whether or not it is true.

Ask a scientist what he conceives the scientific method to be and he will adopt an expression that is at once solemn and shifty-eyed: solemn, because he feels he ought to declare an opinion; shifty-eyed, because he is wondering how to conceal the fact that he has no opinion to declare.

I shall borrow two words used for a slightly different purpose by the great demographer Alfred Lotka to distinguish between the two systems of heredity enjoyed by man: endosomatic or internal heredity for the ordinary or genetical heredity we have in common with animals; and exosomatic or external heredity for the non-genetic heredity that is peculiarly our own - the heredity that is mediated through tradition, by which I mean the transfer of information through non-genetic channels from one generation to the next.

The attempt to discover and promulgate the truth is nevertheless an obligation upon all scientists, one that must be persevered in no matter what the rebuffs—for otherwise what is the point in being a scientist?

I believe in intelligence, and I believe also that there are inherited differences in intellectual ability, but I do not believe that intelligence is a simple scalar endowment that can be quanitified by attaching a single figure to it—an I.Q. or the like.

We cannot point to a single definitive solution of any one of the problems that confront us — political, economic, social or moral, that is, having to do with the conduct of life. We are still beginners, and for that reason may hope to improve. To deride the hope of progress is the ultimate fatuity, the last word in poverty of spirit and meanness of mind. There is no need to be dismayed by the fact that we cannot yet envisage a definitive solution of our problems, a resting-place beyond which we need not try to go.

Simultaneous discovery is utterly commonplace, and it was only the rarity of scientists, not the inherent improbability of the phenomenon, that made it remarkable in the past. Scientists on the same road may be expected to arrive at the same destination, often not far apart.

It is the great glory as well as the great threat of science that everything which is in principle possible can be done if the intention to do it is sufficiently resolute.

A scientist is no more a collector and classifier of facts than a historian is a man who complies and classifies a chronology of the dates of great battles and major discoveries.

All scientists know of colleagues whose minds are so well equipped with the means of refutation that no new idea has the temerity to seek admittance. Their contribution to science is accordingly very small.

Considered in its entirety, psychoanalysis won't do. It is an end product, moreover, like a dinosaur or a zeppelin; no better theory can ever be erected on its ruins, which will remain for ever one of the saddest and strangest of all landmarks in the history of twentieth century thought.

French is not a language that lends itself naturally to the opaque and ponderous idiom of nature-philosophy, and Teilhard has according resorted to the use of that tipsy, euphoristic prose-poetry which is one of the more tiresome manifestations of the French spirit.

The human mind treats a new idea the same way the body treats a strange protein; it rejects it.

How have people come to be taken in by The Phenomenon of Man? We must not underestimate the size of the market for works of this kind [pseudoscience/'woo'], for philosophy-fiction. Just as compulsory primary education created a market catered for by cheap dailies and weeklies, so the spread of secondary and latterly tertiary education has created a large population of people, often with well-developed literary and scholarly tastes, who have been educated far beyond their capacity to undertake analytical thought.

There is much else in the literary idiom of nature-philosophy: nothing-buttery, for example, always part of the minor symptomatology of the bogus.

In no sense other than an utterly trivial one is reproduction the inverse of chemical disintegration. It is a misunderstanding of genetics to suppose that reproduction is only 'intended' to make facsimiles, for parasexual processes of genetical exchange are to be found in the simplest living things.

The Phenomenon of Man stands square in the tradition of Naturphilosophie, a philosophical indoor pastime of German origin which does not seem even by accident (though there is a great deal of it) to have contributed anything of permanent value to the storehouse of human thought.

I do not propose to criticize the fatuous argument I have just outlined; here, to expound is to expose.

Scientists are people of very dissimilar temperaments doing different things in very different ways. Among scientists are collectors, classifiers and compulsive tidiers-up; many are detectives by temperament and many are explorers; some are artists and others artisans. There are poet-scientists and philosopher-scientists and even a few mystics.

Psychoanalytic theory is the most stupendous intellectual confidence trick of the twentieth century and a terminal product as well-something akin to a dinosaur or zeppelin in the history of ideas, a vast structure of radically unsound design and with no posterity.

If the task of scientific methodology is to piece together an account of what scientists actually do, then the testimony of biologists should be heard with specially close attention. Biologists work very close to the frontier between bewilderment and understanding. Biology is complex, messy and richly various, like real life; it travels faster nowadays than physics or chemistry (which is just as well, since it has so much farther to go), and it travels nearer to the ground. It should therefore give us a specially direct and immediate insight into science in the making.

You have ... been told that science grows like an organism. You have been told that, if we today see further than our predecessors, it is only because we stand on their shoulders. But this [Nobel Prize Presentation] is an occasion on which I should prefer to remember, not the giants upon whose shoulders we stood, but the friends with whom we stood arm in arm ... colleagues in so much of my work.

We shall not read it for its sociological insights, which are non-existent, nor as science fiction, because it has a general air of implausibility; but there is one high poetic fancy in the New Atlantis that stays in the mind after all its fancies and inventions have been forgotten. In the New Atlantis, an island kingdom lying in very distant seas, the only commodity of external trade is light: Bacon's own special light, the light of understanding.

Scientific discovery is a private event, and the delight that accompanies it, or the despair of finding it illusory, does not travel. One scientist may get great satisfaction from another's work and admire it deeply; it may give him great intellectual pleasure; but it gives him no sense of participation in the discovery, it does not carry him away, and his appreciation of it does not depend on his being carried away. If it were otherwise the inspirational origin of scientific discovery would never have been in doubt.

A danger sign that fellow-obsessionals will at once recognize is the tendency to regard the happiest moments of your life as those that occur when someone who has an appointment to see you is prevented from coming.

Is the Scientific Paper a Fraud?

It is not envy or malice, as so many people think, but utter despair that has persuaded many educational reformers to recommend the abolition of the English public schools.

Observation is the generative act in scientific discovery. For all its aberrations, the evidence of the senses is essentially to be relied upon provided we observe nature as a child does, without prejudices and preconceptions, but with that clear and candid vision which adults lose and scientists must strive to regain.

It is ... a sign of the times-though our brothers of physics and chemistry may smile to hear me say so-that biology is now a science in which theories can be devised: theories which lead to predictions and predictions which sometimes turn out to be correct. These facts confirm me in a belief I hold most passionately-that biology is the heir of all the sciences.

Scientists who think science consists of unprejudiced data-gathering without speculation are merely cows grazing on the pasture of knowledge.

It is a common failing-and one that I have myself suffered from-to fall in love with a hypothesis and to be unwilling to take no for an answer. A love affair with a pet hypothesis can waste years of precious time. There is very often no finally decisive yes, though quite often there can be a decisive no.

Deductivism in mathematical literature and inductivism in scientific papers are simply the postures we choose to be seen in when the curtain goes up and the public sees us. The theatrical illusion is shattered if we ask what goes on behind the scenes. In real life discovery and justification are almost always different processes.

I do not believe indeed, I deem it a comic blunder to believe that the exercise of reason is sufficient to explain our condition and where necessary to remedy it, but I do believe that the exercise of reason is at all times necessary...

To deride the hope of progress is the ultimate fatuity, the last word in poverty of spirit and meanness of mind.

If a scientist were to cut his ear off, no one would take it as evidence of a heightened sensibility.

When asked to make the formal declaration that I did not intend to overthrow the Constitution of the United States, I was fool enough to reply that I had no such purpose, but that were I to do it by mistake I should be inexpressibly contrite.

The purpose of scientific enquiry is not to compile an inventory of factual information, nor to build up a totalitarian world picture of natural Laws in which every event that is not compulsory is forbidden. We should think of it rather as a logically articulated structure of justifiable beliefs about nature.

The USA is so enormous, and so numerous are its schools, colleges and religious seminaries, many devoted to special religious beliefs ranging from the unorthodox to the dotty, that we can hardly wonder at its yielding a more bounteous harvest of gobbledygook than the rest of the world put together.

The art of research [is] the art of making difficult problems soluble by devising means of getting at them.

Any scientist of any age who wants to make important discoveries must study important problems. Dull or piffling problems yield dull or piffling answers. It is not not enough that a problem should be "interesting." ... The problem must be such that it matters what the answer is-whether to science generally or to mankind.

It goes with the passionate intensity and deep conviction of the truth of a religious belief, and of course of the importance of the superstitious observances that go with it, that we should want others to share it - and the only certain way to cause a religious belief to be held by everyone is to liquidate nonbelievers. The price in blood and tears that mankind generally has had to pay for the comfort and spiritual refreshment that religion has brought to a few has been too great to justify our entrusting moral accountancy to religious belief.

The bells which toll for mankind are—most of them, anyway—like the bells of Alpine cattle; they are attached to our own necks, and it must be our fault if they do not make a cheerful and harmonious sound.

The alternative to thinking in evolutionary terms is not to think at all.

For a scientist must indeed be freely imaginative and yet skeptical, creative and yet a critic. There is a sense in which he must be free, but another in which his thought must be very preceisely regimented; there is poetry in science, but also a lot of bookkeeping.

Scientific reasoning is a kind of dialogue between the possible and the actual, between what might be and what is in fact the case.