The debate between Norton and Brown regarding whether thought experiments transcend empiricism is interesting with Norton suggesting that thought experiments do not transcend empiricism.

If one had to choose a thought experiment to defend Norton's view, would Galileo's thought experiment that two falling bodies fall with the same acceleration be a suitable thought experiment since it can be empirically tested and it also can be written in a premise and conclusion argument form. I am not sure whether this would be a deductive argument though.

Also, wouldn't the assumption that connecting the heavier (H) and lighter (L) body makes one body of weight (H+L) mean that one of the premises of the argument would be false.

Thank you for your help!

  • CriglCragl, That is very helpful. If one had to choose between the following thought experiments to defend the view that thought experiments do not transcend empiricism (John D. Norton's view), which would be the most appropriate and why? 1. Einstein's chasing the light beam 2. Light clock 3. Magnet and conductor 4. Einstein's Elevator 5. Dropping a ball through a hole in the centre of the Earth (to check curvature) Thank you!
    – ADG
    Dec 24, 2018 at 16:09
  • @ADG Riding a light beam. The blackhole firewall paradox seems to be pointing to the need to have systems that unify observers with events. The whole area is a playground of thought experiments, and we are still really just getting to grip with understanding how much we don't understand (eg. the gravity-fluid correspondance).
    – CriglCragl
    Dec 26, 2018 at 0:45
  • Empirically testing that two bodies fall with the same acceleration is not trivial. Try it with pennies over the dining room table. It's going to be hard to make sure they hit the table at the exact same time. If you get into more exact measurements, a penny is likely to fall faster or slower depending on its orientation. Assuming we're using very good instruments in a really hard vacuum, we can test various bodies, but we can't empirically determine that any two bodies will fall with the same acceleration, because we can't test everything. Dec 26, 2018 at 23:21

2 Answers 2


I'm not familiar with that Norton&Brown debate, but it's nevertheless abundantly and historically clear that it's empiricism which transcends thought experiments, rather than the other-way-around.

The enormously famous EPR thought experiment is the historical example I had in mind, e.g., https://en.wikipedia.org/wiki/EPR_paradox   And you'll note that https://en.wikipedia.org/wiki/Bell_test_experiments describes the subsequent empirical experimental evidence contradicting/disproving the earlier EPR thought experiments/conjectures.


Thought experiments test premises, as can be understood from Cartwright's How The Laws of Physics Lie. A mathematical truth is a necessary truth from given abstractions if they are correct, so when an observation disagrees the abstractiins must not be correct. I see thought experiments as in the domain of mathematical truths.

I would pick Maxwell's demon. When it was proposed it was essentially obvious it couldn't work, but it took considerable time and the unification of thermodynamics and information theory to explain why. We needed a more fundamental place to stand, evidence told us, and thought experiment led us to.

Consider the 'thought experiment' of the Many Worlds interpetation - what happens if we just take the equations of quantum mechanics as literally true and all the outcomes as real? The thought experiment can't settle it. We need observations. They always have the final word.

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