The background of this question is as follows. Sean Carroll is in the process of giving a series of talks recorded in his home office and published on YouTube. The setup is intentionally very informal. The overall name of the series is Biggest ideas in the Universe.

Recently, he threw out an on-the-side remark that really annoyed me. Sean Carroll was talking about Ludwig Boltzmann, and about opposition from some of his contemporaries.

Transcript 52:35 into the video:

[...] a lot of people in germany led by Ernst Mach of Mach's principle fame didn't want to believe in the existence of atoms. They thought that things like the second law of thermodynamics were not probabilistic. [...]

So, at the time, what was actually going on? What, in truth, was the attitude of Ernst Mach towards the existence of atoms?

The Stanford Encyclopedia of Philosophy has an article about atomism.

The striking thing about atomism in the 19th century: on one hand there is circumstantial evidence in favor of atomism, in the form of elements tending to combine in particualar ratios, and from kinetic theory of gases. On the other hand, for both lines of circumstantial evidence there were also anomalies. Cases were known where the chemical reaction doesn't show a preferred ratio, cases were known where certain experimental results could not be accounted for in terms of the existing kinetic theory of gases.

In the Stanford Encyclopedia article Ostwald is mentioned. Ostwald was of the opinion that the case for atomism was not conclusive.

Mach's philosophy of science
Mach's philosophy of science was very austere. At the time there was the school of thought called 'Logical Positivism'. As I understand it: in terms of logical positivism only experimental results and the formulas that express the structure of a theory of physics are regarded to fall in realm of science.

In this austere view even interpretation of a theory of physics isn't necessarily science, in the sense that this interpretation may be in part speculative.

So, I can see Ernst Mach arguing that the evidence available at the time does not prove atomism beyond doubt.

Specific question: of the people who opposed the views of Ludwig Boltzman, what was their opinion on the status of atomism?

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    $\begingroup$ Related: Did scientists at some point believe that everything is made out of atoms? For places to look regarding your question, see the references I gave in my comment to this earlier question. A glance at the index of my copy of Mary Jo Nye's book gives 20 page listings under "March, Ernst" and 3 books by Mach are listed in her bibliography. I'll look them up in a moment . . . $\endgroup$ Aug 5, 2020 at 14:08
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    $\begingroup$ The 3 books by March are: [1] Erkenntnis und Irrtum and [2] The Principles Of Physical Optics and [3] The Science of Mechanics $\endgroup$ Aug 5, 2020 at 14:12
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    $\begingroup$ Cercignani (1998) Ludwig Boltzmann: The Man Who Trusted Atoms, Oxford UP, has as chapt. 11 "Boltzmannn and his contemporaries" (view in googlebooks). Btw people used to make a distiction b/n the earlier positivism (e.g. Mach, 19th. c) and the later (20th.c) "logical" positivism. $\endgroup$
    – sand1
    Aug 5, 2020 at 17:55
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    $\begingroup$ Logical positivism only appeared in 1920s, Mach was just a positivist ("empiriocritic"). He did not have a problem with using "mental artifices" to describe "complexes of sensational elements" generally, including a heat fluid, he opposed atoms specifically, and with a fervor that is hard to explain from his philosophy. He stopped using them in his works, complained that they impose too many constraints on "creations of thought", but at the same time are too much of a "mechanical mythology", etc., etc., see Brush, Mach and Atomism. $\endgroup$
    – Conifold
    Aug 5, 2020 at 19:48
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    $\begingroup$ @RodrigodeAzevedo In the case of youtube: with the videos uploaded by Sean Carroll I get the option to open a machine generated transcript. For a machine generated transcript it is stunningly good. 'Ernst Mach' was misspelled as 'Ernst Mock', but obviously I was still perfectly able to find the statement by having a text editor search for the string 'ernst'. So there it is: there is no longer any excuse to quote from memory. (It may be that youtube does not extend the machine transscription to all videos, I don't know about that.) $\endgroup$
    – Cleonis
    Aug 7, 2020 at 13:40


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