Einstein’s debt to philosophy and Hume

Recently it seems to have become fashionable among some scientists, mainly physicists, to harshly disparage philosophy in general and the philosophy and sociology of science in particular. This was not so in times gone by, especially during the time of ferment at the dawn of the twentieth century with the development of theories of relativity and quantum mechanics. While they were developing various successful computational techniques, people struggled to figure out what these theories meant because they seemed to defy our intuitions of how matter behaved at very small scales and when it was traveling very fast.

Even at that time, some eminent physicists spoke somewhat disparagingly of philosophy, such as Paul Dirac saying, “I feel that philosophy will never lead to important discoveries. It is just a way of talking about discoveries which have already been made.” But now that opinion is more widespread among scientists and in my forthcoming book I discuss this development and why it might have occurred.

But one notable exception to this disdain was Albert Einstein and throughout his life, not just in his later years when scientists tend to start philosophizing, he emphasized the importance of philosophy and felt that a scientist was impoverished by not studying it, As Matias Slavov writes, Einstein credits David Hume with giving him a key idea about the nature of time that led to his special theory of relativity.

In 1915, Albert Einstein wrote a letter to the philosopher and physicist Moritz Schlick, who had recently composed an article on the theory of relativity. Einstein praised it: ‘From the philosophical perspective, nothing nearly as clear seems to have been written on the topic.’ Then he went on to express his intellectual debt to ‘Hume, whose Treatise of Human Nature I had studied avidly and with admiration shortly before discovering the theory of relativity. It is very possible that without these philosophical studies I would not have arrived at the solution.’

More than 30 years later, his opinion hadn’t changed, as he recounted in a letter to his friend, the engineer Michele Besso: ‘In so far as I can be aware, the immediate influence of D Hume on me was greater. I read him with Konrad Habicht and Solovine in Bern.’ We know that Einstein studied Hume’s Treatise (1738-40) in a reading circle with the mathematician Conrad Habicht and the philosophy student Maurice Solovine around 1902-03. This was in the process of devising the special theory of relativity, which Einstein eventually published in 1905. It is not clear, however, what it was in Hume’s philosophy that Einstein found useful to his physics. We should therefore take a closer look.

Hume’s philosophy of time shows the fundamental relevance of the relation between an observer and a reference object. There is no evidence for absolute, self-existing time. Nor is there evidence for one universal time. There are different times, depending on the observer/reference-object relation. It is not ‘possible for time alone ever to make its appearance’, as ‘time is nothing but the manner, in which some real objects exist,’ writes Hume. Based on this dictum, in his 2007 biography of Einstein, Walter Isaacson alludes that Hume’s rejection of absolute/universal time ‘would later echo in Einstein’s theory of relativity’.

Slavov goes on to describe how Einstein and Hume’s views are in opposition to Isaac Newton and Immanuel Kant’s concept of time.

The ideas of special relativity were very much in the air when Einstein proposed his special theory. There were experimental anomalies that needed to be explained and the Lorentz transformation was already around. So one could make the case that if Einstein did not exist or propose it, someone else would come along not too long after with the same idea.

But this is not the case for Einstein’s theory of general relativity. Of the three tests of general relativity (the gravitational red shift, the bending of light by gravitational fields, and the rate of precession of the perihelion of Mercury) only the last was known as a problem and it was not seen as an insurmountable one within classical physics. His insight as to what things might look like to someone falling freely in a gravitational field led to his formulation of the Equivalence Principle and later to his General Theory that explained the Mercury problem. This insight was not obvious. As Richard Feynman said:

Einstein himself, of course, arrived at the same Lagrangian but without the help of a developed field theory, and I must admit that I have no idea how he guessed the final result. We have had troubles enough arriving at the theory – but I feel as though he had done it while swimming underwater, blindfolded, and with his hands tied behind his back!

— Feynman Lectures on Gravitation (1995) p.87. Feynman was showing how to derive the theory of general relativity. Even Feynman struggled to understand how Einstein obtained his theory of general relativity given the state of knowledge at the time.

How long might we have gone without realizing that a new theory was needed if Einstein did not have his insight? We now know that if GPS satellites do not make corrections due to the gravitational red shift, then after a day or two they will be off by about 6 miles! So that would definitely have told us that we had a problem. But would we have even reached the stage of putting satellites in space without the General Theory?

It is interesting to speculate but we cannot know. In general, it is not the case that only one person could have come up with a new theory that works well. But what can happen is the time taken for the theory to be proposed and accepted could vary greatly.


  1. Rob Grigjanis says

    We now know that if GPS satellites do not make corrections due to the gravitational red shift, then after a day or two they will be off by about 6 miles!

    I’m aware of the time difference between earth and satellite clocks -- I’ve calculated it using the Schwarzschild metric, and it agrees with results I’ve seen. But I have doubts about the “6 miles a day”.

    You get a number like this by starting with an acceptable distance error -- let’s say 10 metres. Then convert this to a time error by dividing by c. That gives about 3e(-8) seconds. The Δt for earth vs satellite clocks is about 4e(-5) seconds per day, which is about a thousand times the time error, giving in turn a distance error a thousand times 10m. So 10km per day!

    Thing is; why would you divide the distance error by c? It would make more sense to divide it by the speed of the satellite, which would give a daily error of about 10 cm.

    Anyway, I’ll dig into this a bit more when I have time.

  2. Reginald Selkirk says

    National Weather Service Duties Act of 2005
    In which horrible person Rick Santorum sought to prevent the National Weather Service from disseminating weather information directly to the public, on behalf of commercial weather companies which disliked competition -- and which got their data from the NWS.

    And why do I bring this up? Science was originally considered a branch of philosophy. Science has many useful and productive methods -- which it got from philosophy. So science should not feel competition from, nor disdain for, philosophy because it is philosophy.

    Why do some scientists feel disdain for philosophy? I think part of it has to be the misuse of the trappings of philosophy to sell bad thinking. This is seen for example in religious apologetics. The use of philosophical argumentation to convince others without regard for the truth is sophistry, and I suspect this is what puts scientists off.

  3. says

    The scientific method is an epistemological tool -- a way of acquiring knowledge and trying to be reasonably confident that scientific knowledge is true. Scientists should not dismiss philosophy, they should be fist-bumping philosophers -- they are working on the same project.

  4. Matt G says

    And speaking of Feynman:

    “Philosophy of science is as useful to scientists as ornithology is to birds. “

  5. Rob Grigjanis says

    Lassi Hippeläinen @3: Unfortunately, the article you link to promotes a common misconception: that you have to consider SR and GR, as though they are separate.

    Any GR solution we use (like Schwarzschild) will be locally Minkowskian; in other words, it has SR in its bones, and will contain both the “speed” part, and the “gravity hole” part. In the particular case of an object in circular motion about the centre of mass in a Schwarzschild spacetime, the speed part comes from the third term on the right hand side in the second equation here (the one beginning ‘g=’), specifically the dφ² term. The “gravity hole” part comes from the dt² term.

  6. consciousness razor says

    The irony is that positivism[1] was in part inspired by (some conceptions of) relativity.[2] Einstein himself seemed to be on that train early on, and of course that is in a way connected with Humean empiricism, along with ideas from Mach and others who were closer to being his contemporaries.
    In the end, though, he wasn’t going to accept the kind of anti-realism (and the accompanying anti-philosophical stance) which gradually festered out of that. His complaints about the Copenhagen (non-) “interpretation” of QM, or the whole measurement problem if you like, is a clear example which was particularly important for him. But to me, it seems like a bunch of somewhat “new” topics in the early 1900s fit into the general pattern, regarding what the fashionable philosophy of science was like at the time (and for many people even today)…. Behaviorism is another obvious case, although of course those disputes (mainly) involved a different set of scientists.
    [1] Or various flavors of logical empiricism, verificationism, and so forth…. I think it’s all a murky incoherent mess anyway, so take your pick of whatever you want to call the philosophical villains of the 20th century, who thought of themselves as defending the scientific establishment.
    [2] See this article from the SEP for some interesting discussion about that and many other things.

  7. Mano Singham says

    Matt G @#5,

    The origins of the quote are unclear but it has been assigned to various people such as Feynman and Steven Weinberg and others who have quoted it approvingly.

  8. Owlmirror says

    “Philosophy of science is as useful to scientists as ornithology is to birds. “

    Which is an odd comparison to make. Birds are presumably less intelligent and more ignorant than the ornithologists that study them. ¹

    Are scientists supposed to be less intelligent and more ignorant than philosophers of science?

    1: And if the birds were as intelligent as the ornithologists, they could indeed make use of ornithological information. Preyed-upon birds could learn about predators, and predator birds could learn about prey. All could benefit from general environmental and ecological data. (“Hey, it says here that DDT causes thin eggshells. No wonder we’ve been losing so many young! Let’s go build a new nest somewhere where that stuff isn’t used!) Brood parasites might end up either going extinct or changing their reproductive behavior very quickly. (“Wait, this egg doesn’t look like the rest! I’ve heard about this. Quick, fly to the library! Look up “cuckoo egg”! Or maybe “cowbird egg”!)

    And so on.

  9. Owlmirror says

    A few thoughts how to express things that I’ve been noodling about with for a while. Let’s see how well they fly.

    1) Science is the work of forming the most accurate conceptual model or map of empirical reality based on empirical reality itself.

    2) Philosophy, in general, is the study and exploration of concepts. Some concepts, of course, are more useful than others.

    3) Philosophy of science is the study of concepts and methodologies used by scientists in their own studies. Inasmuch as understanding and improving the tools one uses is useful, scientists could benefit from the philosophy of science.

  10. Mano Singham says


    I read the quote as not saying anything about intelligence but that just as birds can fly perfectly well without knowing any ornithology, so can scientists function perfectly well without any knowledge of the philosophy of science.

  11. Rob Grigjanis says

    Further to my #1:

    As the link supplied by Lassi Hippeläinen @3 makes clear, the 10 km a day isn’t the error in position on the Earth’s surface. It’s the error in the pseudorange; the distance between satellite and receiver as defined by c times (time taken for signal from satellite to receiver).

    I’d have noticed this earlier if I hadn’t stopped reading after the SR and GR nonsense! 🙁

  12. says

    @Matt G, #5:

    “Philosophy of science is as useful to scientists as ornithology is to birds.”

    So… incredibly useful then? I mean, it’s clear ornithology has been of benefit to, say, the California Condor to name just one species off the top of my head.

    Imagine how scientists would argue for grant money before congress without philosophy:

    CongressCritter: “Why should we fund your discipline? Many people believe we should no longer have university departments dedicated to your discipline, and even if private universities do choose to have such departments, the government is under no obligation to do so. I presume eliminating all national funding would thus be acceptable to you?”

    Scientist: “Um, I don’t know. I could commission an empirical study on nation-states who don’t fund my discipline and nation states who do fund my discipline, but we’d have to start out with a hypothesis about what sorts of things are ‘worth’ government funding, and then see how funding our discipline impacts those things known to be worth funding. But I’m struggling with this concept of ‘worth’.”

    CongressCritter: “So I see. Perhaps you could come back next month and present your justification.”

    Scientist: “Justification? I could present a scatterplot of my most recent data with a best fit regression curve. Does that justify funding?”

    CongressCritter: “Well, if even you’re not sure whether or not you have any justification for funding your discipline, we’ll just cut it out of the budget without worrying about next month. Thanks for dropping by.”

    Of course, they could leave such testimony to the philosophers of science, but then PoS would still be useful to them, they just wouldn’t understand it. Much like Silicon-on-Insulator fabrication techniques are useful to me, regardless of my level of understanding.

  13. Matias Slavov says

    Thank you for the interesting post and discussing the Aeon piece.
    Your forthcoming book sounds intriguing. Have you devised the table of contents?

  14. Mano Singham says

    Matias @#16,

    Thanks for the comment. Actually, the entire book is written and only the final proofs need to be checked. It should appear in stores towards the end of this year or very early next year.

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