Both Mach and Norton hold empiricist views on the notions of the role of thought experiments.

Could someone please explain the difference? Have done some reading but it’s not totally clear.

  • 2
    I think your question could be much improved by giving a little more context ... or maybe just a quote from Mach and Norton. Also, please express what your current thoughts are, even if you are not totally clear; it helps to focus what exactly it is you are struggling with.
    – Bram28
    Commented Jan 1, 2019 at 14:13

1 Answer 1


Ernst Mach made a good point that any sensibly designed real experiment should be preceded by a thought experiment that anticipates, at any rate, the possibility of its outcome.

Mach's empiricism is complicated. It has its roots in the belief that knowledge is a product of evolution, that our senses, minds, and cultures have an evolutionary history.

It was a simple experience to which early organisms responded, and it was out of simple experiences that the first images of the world were constructed.

The views of Norton represent the extremes of platonic rationalism and classic empiricism, respectively.

Norton claims that any thought experiment is really an argument;

it starts with premises grounded in experience and follows deductive or inductive rules of inference in arriving at its conclusion.

The picturesque features of any thought experiment which give it an experimental flavor might be psychologically helpful but are strictly redundant.

Thus, says Norton, we never go beyond the empirical premises in a way to which any empiricist would object.

There are three objections that might be offered against Norton.

First, his notion of argument is too vague. However, this might not be the best objection: arguments can be deductive (which are perfectly clear) or inductive. If the latter is unclear, the fault is with induction, not with Norton's argument view.

Second, it is argued that Norton simply begs the question: every real-world experiment can be rephrased as an argument, but nobody would say that real-world arguments are dispensable.

The account does not address the question: where do the premises come from? A thought experiment might be an essential step in making the Norton-style reconstruction.

Third, a thought experiment that is presented in argument form loses its typical force. The soft-point in Brown's Platonism is linked to the strength of Norton's account because Norton claims that any other view implies a commitment to “asking the oracle.” “Imagine an oracle that claims mysterious powers but never delivers predictions that could not be learned by simple inferences from ordinary experience. We would not believe that the oracle had any mysterious powers. I propose the same verdict for thought experiments in science.” (Norton, 1996, pp. 1142–1143)

Defenders of empiricist alternatives deny this dispensability thesis.

By contrast, Brown holds that in a few special cases we do go well beyond the old data to acquire a priori knowledge of nature. (See also Koyré 1968.) Galileo showed that all bodies fall at the same speed with a brilliant thought experiment that started by destroying the then reigning Aristotelian account.

Thomas Kuhn's "A Function for Thought Experiments" employs many of the concepts (but not the terminology) of his well-known Structure of Scientific Revolutions.

On his view, a well-conceived thought experiment can bring on a crisis or at least create an anomaly in the reigning theory and so contribute to paradigm change.

Thought experiments can teach us something new about the world, even though we have no new empirical data, by helping us to re-conceptualize the world in a better way. Tamar Gendler has recently developed this view in a number of important respects.


  • some good facts, but the answer could hang together better, imho... are you saying that the main difference between mach / norton is that the former "deny this dispensibility thesis"? and the 3rd paragraph ending "respectively" looks odd
    – user35983
    Commented Jan 2, 2019 at 11:59
  • confused- I agree the "respectively" term is not necessary. Not being a philosopher is a handicap and I am trying to learn by collecting info about the two approaches- I find several examples from modern science about thought experiments esp. in physical sciences but could not post it.. but they go against Norton's approach.
    – drvrm
    Commented Jan 2, 2019 at 20:20

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