I'm confused about a statement by Israel Gelfand given in the book TOPSY TURVY: A Book for All in One Page No:155

Why did Israel Gelfand say “You have to be fast only to catch fleas,” and how does this phrase apply to researchers?

  • 9
    This quote basically implies you can be slow for "big results" but I'm not really sure it's accurate anymore except in some exceptional cases like Fermats Last Theorem. The quantity of papers coming out continues to grow. Doing any type of original work is becoming increasingly difficult for every field. Mar 4, 2021 at 2:17
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    @FourierFlux Ah, but the questions considered and our toolboxes also continue to grow. I'm not convinced that research is getting more difficult---it's always been hard---though how people do research has changed.
    – Kimball
    Mar 4, 2021 at 11:39
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    "Unless your objective is catching fleas, you dont need to worry about being fast"
    – Strawberry
    Mar 4, 2021 at 15:30
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    It would be useful if you can give more of the context preceding the quote, for the benefit of those of us who don’t have this book.
    – Dan Romik
    Mar 4, 2021 at 16:12
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    Also the book you are quoting seems like a book of random quotes, some of them mis-translated, misappropriated or taken out of context.
    – Tom
    Mar 4, 2021 at 20:40

5 Answers 5


To me, at least, the metaphor seems clear. Anyone can pick up pennies off the street, but it takes hard work and time to amass a fortune. Hmmm. Another metaphor.

If you want to make a reputation publishing trivial (or small) results, then you have to be fast, since they are available to most mathematicians in a subfield. But if you want to do great things (catch bears, for example), it will take time and effort. It will, necessarily be slower and that is ok as the results are more profound.

The word "only" in the quote is very important. Yes, you need to be fast to catch small, fleeting, things, but only for that. Without that word, the meaning would be entirely different.

Gelfand, of course, is known for some pretty profound work. They didn't result from 3 week research projects.

And, this is only my speculation, since he can't be asked directly.

  • 40
    Just to add that this is quite a common expression in Russian, and the gist is essentially correct: no need to rush, we aren't hunting fleas here. Mar 3, 2021 at 16:08
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    No, I don't think that's quite the same meaning. I'd say "You only have to be fast to catch fleas" as in, if you want to catch fleas, you have to be fast with the implication being that if you want to catch something bigger, speed is less important.
    – Foon
    Mar 3, 2021 at 22:19
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    Inferring from this and my language knowledge, it might be (for a better result the original quote is needed) the counterpart of the English saying "Nothing must be done hastily but killing of fleas." But the Russian counterpart means to me merely "don't be in haste", "don't rush things". Mar 3, 2021 at 22:25
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    @Federico, no, "fleas" sounds better in Russian, although the two words are just as close. But the main difference is that it's practical: nobody really catches flies by hand: there are better methods. Whereas catching fleas was common (well, still is: I recently caught a flea on my dog), and you need to be really quick before it jumps off and disappears (as is well known, fleas are record jumpers with respect to their size).
    – Zeus
    Mar 4, 2021 at 23:26
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    The word order in the question is in fact the most appropriate one, but the contrapositive might convey the literal meaning more clearly: "You do not need to be fast for any reason other than to catch fleas". If instead the quotation were "You only need to be fast to catch fleas" then the most ready interpretation would be that speed is sufficient for flea catching. Mar 5, 2021 at 2:03

This is just speculation, but as a native Russian speaker, I'm pretty sure this is a literal translation of a Russian saying, better translated as "You only need haste when catching fleas" (Спешка нужна только при ловле блох). Since Israel Gelfand had lived in USSR, I think it's pretty likely he was referencing it.

It's pretty much a generic "haste makes waste" proverb that means you shouldn't rush and that you should think before doing something.

  • I would vote this answer up if you could convince me with a citation or two that this information is correct. Mar 12, 2021 at 17:14
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    @MatthewChristopherBartsh No citations are required to offer an example of an aphorism popular in some part of the world. This is for the same reason that 0 is the minimum sample size required to be statistically certain that at least 50% of Americans over the age of 30 have eaten ice-cream at least once in their lifetime. I mean, you could round up 10,000 people, ask them a yes or no question (have you eaten ice-cream before?), assume that there is an underlying binomial distribution, etc... define a null and alternative hypothesis, report a p-value, but that would all be a waste of time. Jun 14, 2021 at 6:34

Not an answer, but another "catch a flea" quote from a mathematician.

In guessing a conundrum, or in catching a flea, we do not expect the breathless victor to give us afterwards, in cold blood, a history of the mental or muscular efforts by which he achieved success; but a mathematical calculation is another thing.

Lewis Carroll
A Tangled Tale
Answers to Knot 4


I am only speculating, but the meaning in this context seems clear to me: "You only need to be quick about generating and publishing material when the material is relatively trivial." The implication is that you can take your time, not only not rushing, but even being somewhat slow, when you are generating momentous material, that is to say, solving big problems.

Furthermore, "fleas" may allude to opportunities to generate trivial new mathematical content in the form of minor nitpicks, adjustments, corrections, and additions to a recently published big breakthrough. These "fleas" are thus perhaps small spin-offs from recent breakthroughs that are easily seen by everyone. There may be an allusion to a woolly mammoth or other large animal, brought down by some great hunter, that has fleas on it. You would need to be quick if you are to catch one or more of them before they have been caught by other hunters.

I also get a sense that catching fleas is not something to be proud of.

"You have to be fast only to catch fleas" unfortunately (I just realized) could be taken to mean, instead, "You always need to be fast. Even to catch only fleas, you have to be fast" In the context of mathematical research, that would mean you always need to quickly publish results, even trivial ones. If Gelfand meant "You don't have to be fast except to catch fleas", perhaps he should have said so, or "You only have to be fast to catch fleas".


I don't think this is accurate any more, unfortunately people are expected to come up even with big results with a reasonable amount of speed. Wiles and Fermat's Last Theorem is a bit of an exception if I remember rightly, as he was salami slicing and publishing intermediate results as separate papers on the way to the proof to give the illusion of productivity (see the book by Singh).

Edit: I am aware that Wiles was publishing important articles in this period and I am just paraphrasing his own words from an interview, but I appreciate that he was being modest/self-deprecating and simplifying what actually happened to make it understandable at a popular level.

I'm also interested in the extent to which this applies to scientific research and physics. I guess it still applies but then there really is a race for results and sometimes time is of the essence. In general a lot of emphasis is given towards those people that can make very quick (not necessarily non-trivial) extensions of other people's work or to come up with quick explanations of recent experimental results.

In physics, Einstein said he had no time for those physicists who 'find where the board is thin and drill lots of small holes' ie. he was interested in things which took a lot of thought and conceptual understanding rather than just choosing what looked to be an area with lots of quick results which can be obtained with relative ease and speed.

  • Looking over Wiles's publication record (as I did just now) does not bear out a claim of "salami slicing": in the period from 1986 to 1993 he has several papers that are really excellent in every sense (solving important problems, published in the best journals, with lots of citations...) If I remember correctly, what he said was that he had important results from before 1986 and he took his time writing them up. That may be the case...or it may be that he was not being entirely serious. Note that he dared to have no publications from 2008 to 2015. Jun 17, 2021 at 20:33
  • But I agree with your first sentence, and I upvoted your answer. What Wiles gets away with many years after he became one of the world's most celebrated mathematicians has little do with the pressures that other (especially younger) mathematicians face. Jun 17, 2021 at 20:35
  • I am just paraphrasing something that he said himself in some interview (I think in the popular book by Singh). I appreciate that this very much has to be taken with a pinch of salt, as he was simplifying a lot to get his point across in that interview.
    – Tom
    Jun 17, 2021 at 21:16
  • As you say, he may just have been being self-deprecating or not totally serious.
    – Tom
    Jun 17, 2021 at 21:32

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