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I wondered whether thought experiments actually can be substituted for actual experimentation. I understand that in some cases it might be necessary, but can it be unnecessary over thinking sometimes? Which can cause controversial understanding of that subject.

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I haven't thought about it :) – Nilotpal Sinha Apr 26 '13 at 6:01
The problem with thought experiments is that they are often difficult to reproduce. – user1504 Apr 26 '13 at 11:54
Thought experiments are of paramount importance in theoretical physics, and of course qualify they as perfectly good research! This question seems not constructive. – Dilaton May 14 '13 at 14:44
@Dilaton He asked can/why a thought experiment, something that relies on our perceptions and expectations, qualify as research. I would take the position that they are a logical/philosophical device that can lead to actual research or explain the results of research, but are not research themselves, Sounds like you disagree. Just because the answer, in your opinion, is "of course!" doesn't make the question unconstructive. user1504 makes the same argument, and Nilotpal always took them for granted. Sounds like a constructive question to me, given the disagreement. – David Schwartz Sep 18 '14 at 21:13

Physics is the construction of mathematical models that describe the real world. For example, when Einstein formulated General Relativity it was just a mathematical model. Not until Eddington (debatably) observed the light bending predicted by the theory did it become accepted as describing the real world.

So research can be split (although it's a slightly artificial separation) into two parts: the theoretical construction of the models and the experimental testing of the models. Thought experiments are an essential part of model construction. They can assist with the formulation of models and test for internal consistency. For example, Einstein claimed that it was his thought experiment of an observer in a freely falling lift that guided him towards the construction of GR.

There are areas of physics where experiment has fallen far behind the theoreticians, notoriously in the area of quantum gravity. Whether this renders further thought experiment unnecessary is debatable. My own view is that while we can afford to build cruise missiles we can afford to provide theoreticians with pencils and paper (and wastebaskets, unless they're working in (insert your least favourite area here) in which case the wastebaskets aren't needed :-).

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"unless they're working in" ? - software? Nebraska? playdough? conjunction with cats? academia? a dumpster? – RedGrittyBrick Apr 26 '13 at 9:58
There's an old joke: maths departments are cheap to run because you only need pencils, paper and wastebaskets. Philosophy departments are even cheaper because you don't need the wastebaskets :-) – John Rennie Apr 26 '13 at 11:45
How about the Quantum Suicide? Immortality? How do we explain that? just by thought. What is the basis of such experiments? – Chandough Apr 26 '13 at 19:16
The Quantum Suicide/Immortality thought experiments are intended to examine some of the consequences of the Many Worlds interpretation of quantum mechanics. They are perfectly valid experiments, though it isn't clear to me how much they tell us. – John Rennie Apr 27 '13 at 6:13
@JohnRennie Great answer! You convinced me. – David Schwartz Sep 18 '14 at 21:14

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