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Francis Crick
(8 Jun 1916 - 28 Jul 2004)
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Science Quotes by Francis Crick (55 quotes)
>> Click for Francis Crick Quotes on | DNA | Life | Molecular Biology | Structure Of DNA | Watson_James |
>> Click for Francis Crick Quotes on | DNA | Life | Molecular Biology | Structure Of DNA | Watson_James |
[Doubtful attribution; from docudrama script] Big questions get big answers.
— Francis Crick
[Our work on the structure of DNA] was fairly fast, but you know, we were lucky. One must remember, it was based on the X-ray work done here in London started off by Morris Wilkins and carried on by Rosalind Franklin, and we wouldn’t have got to the stage of at least having a molecular model, if it hadn't been for their work.
— Francis Crick
[Resist the temptation to] work so hard that there is no time left for serious thinking …[Scientists] should heed the saying, “A busy life is a wasted life.”
— Francis Crick
~~[need primary source]~~ One of the most frightening things in the Western world and in this country in particular is the number of people who believe in things that are scientifically false. If someone tells me that the earth is less than 10000 years old in my opinion he should see a psychiatrist.
— Francis Crick
A comparison between the triplets tentatively deduced by these methods with the changes in amino acid sequence produced by mutation shows a fair measure of agreement.
— Francis Crick
A final proof of our ideas can only be obtained by detailed studies on the alterations produced in the amino acid sequence of a protein by mutations of the type discussed here.
— Francis Crick
Again the message to experimentalists is: Be sensible but don’t be impressed too much by negative arguments. If at all possible, try it and see what turns up. Theorists almost always dislike this sort of approach.
— Francis Crick
Almost all aspects of life are engineered at the molecular level, and without understanding molecules we can only have a very sketchy understanding of life itself.
— Francis Crick
Altering a gene in the gene line to produce improved offspring is likely to be very difficult because of the danger of unwanted side effects. It would also raise obvious ethical problems.
— Francis Crick
An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle, so many are the conditions which would have had to have been satisfied to get it going. But this should not be taken to imply that there are good reasons to believe that it could not have started on the earth by a perfectly reasonable sequence of fairly ordinary chemical reactions. The plain fact is that the time available was too long, the many microenvironments on the earth’s surface too diverse, the various chemical possibilities too numerous and our own knowledge and imagination too feeble to allow us to be able to unravel exactly how it might or might not have happened such a long time ago, especially as we have no experimental evidence from that era to check our ideas against.
— Francis Crick
And so to those of you who may be vitalists I would make this prophecy: what everyone believed yesterday, and you believe today, only cranks will believe tomorrow.
— Francis Crick
Attempts have been made from a study of the changes produced by mutation to obtain the relative order of the bases within various triplets, but my own view is that these are premature until there is more extensive and more reliable data on the composition of the triplets.
— Francis Crick
Biologists must constantly keep in mind that what they see was not designed, but rather evolved.
— Francis Crick
Chance is the only source of true novelty.
— Francis Crick
Eventually the process of aging, which is unlikely to be simple, should be understandable. Hopefully some of its processes can be slowed down or avoided. In fact, in the next century, we shall have to tackle the question of the preferred form of death.
— Francis Crick
Exact knowledge is the enemy of vitalism.
— Francis Crick
Finally one should add that in spite of the great complexity of protein synthesis and in spite of the considerable technical difficulties in synthesizing polynucleotides with defined sequences it is not unreasonable to hope that all these points will be clarified in the near future, and that the genetic code will be completely established on a sound experimental basis within a few years.
— Francis Crick
Haemoglobin is a very large molecule by ordinary standards, containing about ten thousand atoms, but the chances are that your haemoglobin and mine are identical, and significantly different from that of a pig or horse. You may be impressed by how much human beings differ from one another, but if you were to look into the fine details of the molecules of which they are constructed, you would be astonished by their similarity.
— Francis Crick
I also suspect that many workers in this field [molecular biology] and related fields have been strongly motivated by the desire, rarely actually expressed, to refute vitalism.
— Francis Crick
I argued that it was important not to place too much reliance on any single piece of experimental evidence. It might turn out to be misleading, as the 5.1 Å reflection undoubtedly was. Jim was a little more brash, stating that no good model ever accounted for all the facts, since some data was bound to be misleading if not plain wrong. A theory that did fit all the data would have been “carpentered” to do so and would thus be open to suspicion.
— Francis Crick
I think she [Rosalind Franklin] was a good experimentalist but certainly not of the first rank. She was simply not in the same class as Eigen or Bragg or Pauling, nor was she as good as Dorothy Hodgkin. She did not even select DNA to study. It was given to her. Her theoretical crystallography was very average.
— Francis Crick
I wasn’t aware of Chargaff’s rules when he said them, but the effect on me was quite electric because I realized immediately that if you had this sort of scheme that John Griffith was proposing, of adenine being paired with thymine, and guanine being paired with cytosine, then you should get Chargaff’s rules.
I was very excited, but I didn’t actually tell Chargaff because it was something I was doing with John Griffith. There was a sort of musical comedy effect where I forgot what the bases were and I had to go to the library to check, and I went back to John Griffith to find out which places he said. Low and behold, it turned out that John Griffith’s ideas fitted in with Chargaff’s rules!
This was very exciting, and we thought “ah ha!” and we realized—I mean what anyone who is familiar with the history of science ought to realize—that when you have one-to-one ratios, it means things go to together. And how on Earth no one pointed out this simple fact in those years, I don’t know.
I was very excited, but I didn’t actually tell Chargaff because it was something I was doing with John Griffith. There was a sort of musical comedy effect where I forgot what the bases were and I had to go to the library to check, and I went back to John Griffith to find out which places he said. Low and behold, it turned out that John Griffith’s ideas fitted in with Chargaff’s rules!
This was very exciting, and we thought “ah ha!” and we realized—I mean what anyone who is familiar with the history of science ought to realize—that when you have one-to-one ratios, it means things go to together. And how on Earth no one pointed out this simple fact in those years, I don’t know.
— Francis Crick
If Watson and I had not discovered the [DNA] structure, instead of being revealed with a flourish it would have trickled out and that its impact would have been far less. For this sort of reason Stent had argued that a scientific discovery is more akin to a work of art than is generally admitted. Style, he argues, is as important as content. I am not completely convinced by this argument, at least in this case.
— Francis Crick
If, for example, I had some idea, which, as it turned out would, say, be quite wrong, was going off of the tangent, Watson would tell me in no uncertain terms this was nonsense, and vice-versa. If he had some idea I didn’t like and I would say so and this would shake his thinking about it and draw him back again. And in fact, it’s one of the requirements for collaboration of this sort that you must be perfectly candid, one might almost say rude, to the person you are working with. It’s useless, working with somebody who’s either much too junior than yourself, or much too senior, because then politeness creeps in. And this is the end of all real collaboration in science.
— Francis Crick
In my experience most mathematicians are intellectually lazy and especially dislike reading experimental papers. He (René Thom) seemed to have very strong biological intuitions but unfortunately of negative sign.
— Francis Crick
In nature hybrid species are usually sterile, but in science the reverse is often true. Hybrid subjects are often astonishingly fertile, whereas if a scientific discipline remains too pure it usually wilts.
— Francis Crick
It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.
[Concluding remark in the paper by Watson and Crick announcing discovery of the structure of DNA.]
[Concluding remark in the paper by Watson and Crick announcing discovery of the structure of DNA.]
— Francis Crick
It is not easy to convey, unless one has experienced it, the dramatic feeling of sudden enlightenment that floods the mind when the right idea finally clinches into place.
— Francis Crick
It is notoriously difficult to define the word living.
— Francis Crick
It is one of the striking generalizations of biochemistry—which surprisingly is hardly ever mentioned in the biochemical text-books—that the twenty amino acids and the four bases, are, with minor reservations, the same throughout Nature. As far as I am aware the presently accepted set of twenty amino acids was first drawn up by Watson and myself in the summer of 1953 in response to a letter of Gamow's.
— Francis Crick
It might be thought … that evolutionary arguments would play a large part in guiding biological research, but this is far from the case. It is difficult enough to study what is happening now. To figure out exactly what happened in evolution is even more difficult. Thus evolutionary achievements can be used as hints to suggest possible lines of research, but it is highly dangerous to trust them too much. It is all too easy to make mistaken inferences unless the process involved is already very well understood.
— Francis Crick
Jim and I hit it off immediately, partly because our interests were astonishingly similar and partly, I suspect, because a certain youthful arrogance, a ruthlessness, an impatience with sloppy thinking can naturally to both of us.
— Francis Crick
My own prejudices are exactly the opposite of the functionalists’: “If you want to understand function, study structure.” I was supposed to have said in my molecular biology days. (I believe I was sailing at the time.)
— Francis Crick
My own thinking (and that of many of my colleagues) is based on two general principles, which I shall call the Sequence Hypothesis and the Central Dogma. The direct evidence for both of them is negligible, but I have found them to be of great help in getting to grips with these very complex problems. I present them here in the hope that others can make similar use of them. Their speculative nature is emphasized by their names. It is an instructive exercise to attempt to build a useful theory without using them. One generally ends in the wilderness.
The Sequence Hypothesis
This has already been referred to a number of times. In its simplest form it assumes that the specificity of a piece of nucleic acid is expressed solely by the sequence of its bases, and that this sequence is a (simple) code for the amino acid sequence of a particular protein...
The Central Dogma
This states that once 'information' has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein. This is by no means universally held—Sir Macfarlane Burnet, for example, does not subscribe to it—but many workers now think along these lines. As far as I know it has not been explicitly stated before.
The Sequence Hypothesis
This has already been referred to a number of times. In its simplest form it assumes that the specificity of a piece of nucleic acid is expressed solely by the sequence of its bases, and that this sequence is a (simple) code for the amino acid sequence of a particular protein...
The Central Dogma
This states that once 'information' has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein. This is by no means universally held—Sir Macfarlane Burnet, for example, does not subscribe to it—but many workers now think along these lines. As far as I know it has not been explicitly stated before.
— Francis Crick
One can say, looking at the papers in this symposium, that the elucidation of the genetic code is indeed a great achievement. It is, in a sense, the key to molecular biology because it shows how the great polymer languages, the nucleic acid language and the protein language, are linked together.
— Francis Crick
Only time and money stand between us and knowing the composition of every gene in the human genome.
— Francis Crick
Protein synthesis is a central problem for the whole of biology, and that it is in all probability closely related to gene action.
— Francis Crick
Rather than believe that Watson and Crick made the DNA structure, I would rather stress that the structure made Watson and Crick.
— Francis Crick
The Astonishing Hypothesis is that “You,” your joys and your sorrows, your memories and your ambitions, your sense of identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll’s Alice might have phrased it: “You’re nothing but a pack of neurons.”
— Francis Crick
The job of theorists, especially in biology, is to suggest new experiments. A good theory makes not only predictions, but surprising predictions that then turn out to be true. (If its predictions appear obvious to experimentalists, why would they need a theory?)
— Francis Crick
The layman is delighted to learn that after all, in spite of science being so impossibly difficult to understand, Scientists Are Human!
— Francis Crick
The major credit I think Jim and I deserve … is for selecting the right problem and sticking to it. It’s true that by blundering about we stumbled on gold, but the fact remains that we were looking for gold. Both of us had decided, quite independently of each other, that the central problem in molecular biology was the chemical structure of the gene. … We could not see what the answer was, but we considered it so important that we were determined to think about it long and hard, from any relevant point of view.
— Francis Crick
The ultimate aim of the modern movement in biology is in fact to explain all biology in terms of physics and chemistry.
— Francis Crick
There is no form of prose more difficult to understand and more tedious to read than the average scientific paper.
— Francis Crick
To produce a really good biological theory one must try to see through the clutter produced by evolution to the basic mechanisms lying beneath them, realizing that they are likely to be overlaid by other, secondary mechanisms. What seems to physicists to be a hopelessly complicated process may have been what nature found simplest, because nature could only build on what was already there.
— Francis Crick
Trying to determine the structure of a protein by UV spectroscopy was like trying to determine the structure of a piano by listening to the sound it made while being dropped down a flight of stairs.
— Francis Crick
Watson and I had been often discussing the problem, the ways you could go wrong solving problems of this sort, the techniques you have to use, and in particular, such rather curious things as you mustn’t pay too much attention to the all the experimental evidence, some of it may be wrong, for example.
— Francis Crick
We knew that DNA was important. We knew it was an important molecule. And we knew that its shape was likely to be important. But we didn’t realise I think just how important it would be. Put in other words, we didn’t realise that the shape would give us a clue to the replication mechanism. And this turned out to be really an unexpected dividend from finding out what the shape was.
— Francis Crick
We wish to suggest a structure for the salt of deoxyribose nucleic acid (DNA). This structure has novel features which are of considerable biological interest.
[Opening remark in the paper by Watson and Crick announcing discovery of the structure of DNA.]
[Opening remark in the paper by Watson and Crick announcing discovery of the structure of DNA.]
— Francis Crick
What is found in biology is mechanisms, mechanisms built with chemical components and that are often modified by other, later, mechanisms added to the earlier ones.
— Francis Crick
When the war finally came to an end, 1 was at a loss as to what to do. ... I took stock of my qualifications. A not-very-good degree, redeemed somewhat by my achievements at the Admiralty. A knowledge of certain restricted parts of magnetism and hydrodynamics, neither of them subjects for which I felt the least bit of enthusiasm.
No published papers at all … [Only gradually did I realize that this lack of qualification could be an advantage. By the time most scientists have reached age thirty they are trapped by their own expertise. They have invested so much effort in one particular field that it is often extremely difficult, at that time in their careers, to make a radical change. I, on the other hand, knew nothing, except for a basic training in somewhat old-fashioned physics and mathematics and an ability to turn my hand to new things. … Since I essentially knew nothing, I had an almost completely free choice. …
No published papers at all … [Only gradually did I realize that this lack of qualification could be an advantage. By the time most scientists have reached age thirty they are trapped by their own expertise. They have invested so much effort in one particular field that it is often extremely difficult, at that time in their careers, to make a radical change. I, on the other hand, knew nothing, except for a basic training in somewhat old-fashioned physics and mathematics and an ability to turn my hand to new things. … Since I essentially knew nothing, I had an almost completely free choice. …
— Francis Crick
When there is publicity about [UFO] sightings that turn out to be explainable, the percentage of unexplained sightings goes up, suggesting that these, too, are caused by something in people’s psychology rather than by something that is actually out there. The UFO evidence forms no coherent residue; it never gets better.
— Francis Crick
When you start in science, you are brainwashed into believing how careful you must be, and how difficult it is to discover things. There’s something that might be called the “graduate student syndrome”; graduate students hardly believe they can make a discovery.
— Francis Crick
While DNA could be claimed to be both simple and elegant, it must be remembered that DNA almost certainly originated fairly close to the origin of life when things were necessarily simple or they would not have got going.
— Francis Crick
While Occam’s razor is a useful tool in the physical sciences, it can be a very dangerous implement in biology. It is thus very rash to use simplicity and elegance as a guide in biological research.
— Francis Crick
Quotes by others about Francis Crick (7)
The central dogma, enunciated by Crick in 1958 and the keystone of molecular biology ever since, is likely to prove a considerable over-simplification. That is the heretical but inescapable conclusion stemming from experiments done in the past few months in two laboratories in the United States.
At lunch Francis [Crick] winged into the Eagle to tell everyone within hearing distance that we had found the secret of life.
The fundamental biological variant is DNA. That is why Mendel's definition of the gene as the unvarying bearer of hereditary traits, its chemical identification by Avery (confirmed by Hershey), and the elucidation by Watson and Crick of the structural basis of its replicative invariance, are without any doubt the most important discoveries ever made in biology. To this must be added the theory of natural selection, whose certainty and full significance were established only by those later theories.
I think that the formation of [DNA's] structure by Watson and Crick may turn out to be the greatest developments in the field of molecular genetics in recent years.
And now the announcement of Watson and Crick about DNA. This is for me the real proof of the existence of God.
Sodium thymonucleate fibres give two distinct types of X-ray diagram … [structures A and B]. The X-ray diagram of structure B (see photograph) shows in striking manner the features characteristic of helical structures, first worked out in this laboratory by Stokes (unpublished) and by Crick, Cochran and Vand2. Stokes and Wilkins were the first to propose such structures for nucleic acid as a result of direct studies of nucleic acid fibres, although a helical structure had been previously suggested by Furberg (thesis, London, 1949) on the basis of X-ray studies of nucleosides and nucleotides.
While the X-ray evidence cannot, at present, be taken as direct proof that the structure is helical, other considerations discussed below make the existence of a helical structure highly probable.
While the X-ray evidence cannot, at present, be taken as direct proof that the structure is helical, other considerations discussed below make the existence of a helical structure highly probable.
We wish to put forward a radically different structure for the salt of deoxyribose nucleic acid. This structure has two helical chains each coiled round the same axis (see diagram).
[Co-author with Francis Crick]
[Co-author with Francis Crick]
See also:
- 8 Jun - short biography, births, deaths and events on date of Crick's birth.
- Francis Crick: Hunter of Life's Secrets, by Robert Olby. - book suggestion.
- Francis Crick: Discoverer of the Genetic Code, by Matt Ridley. - book suggestion.
- Astonishing Hypothesis: The Scientific Search for the Soul, by Francis Crick. - book suggestion.
- Of Molecules and Men, by Francis Crick. - book suggestion.
- Life Itself: Its Origin and Nature, by Francis Crick. - book suggestion.
- What Mad Pursuit: A Personal View of Scientific Discovery, by Francis Crick. - book suggestion.