---
title: "Thought experiment"
chunk: 3/3
source: "https://en.wikipedia.org/wiki/Thought_experiment"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:12:59.237630+00:00"
instance: "kb-cron"
---

=== Possibility ===
In many thought experiments, the scenario would be nomologically possible, or possible according to the laws of nature. John Searle's Chinese room is nomologically possible.
Some thought experiments present scenarios that are not nomologically possible. In his Twin Earth thought experiment, Hilary Putnam asks us to imagine a scenario in which there is a substance with all of the observable properties of water (e.g., taste, color, boiling point), but is chemically different from water.  It has been argued that this thought experiment is not nomologically possible, although it may be possible in some other sense, such as metaphysical possibility.  It is debatable whether the nomological impossibility of a thought experiment renders intuitions about it moot.
In some cases, the hypothetical scenario might be considered metaphysically impossible, or impossible in any sense at all. David Chalmers says that we can imagine that there are zombies, or persons who are physically identical to us in every way but who lack consciousness. This is supposed to show that physicalism is false. However, some argue that zombies are inconceivable: we can no more imagine a zombie than we can imagine that 1+1=3. Others have claimed that the conceivability of a scenario may not entail its possibility.

=== Causal reasoning ===
The first characteristic pattern that thought experiments display is their orientation
in time. They are either:

Antefactual speculations: experiments that speculate about what might have happened prior to a specific, designated event, or
Postfactual speculations: experiments that speculate about what may happen subsequent to (or consequent upon) a specific, designated event.
The second characteristic pattern is their movement in time in relation to "the present
moment standpoint" of the individual performing the experiment; namely, in terms of:

Their temporal direction: are they past-oriented or future-oriented?
Their temporal sense:
(a) in the case of past-oriented thought experiments, are they examining the consequences of temporal "movement" from the present to the past, or from the past to the present? or,
(b) in the case of future-oriented thought experiments, are they examining the consequences of temporal "movement" from the present to the future, or from the future to the present?

=== Relation to real experiments ===
The relation to real experiments can be quite complex, as can be seen again from an example going back to Albert Einstein. In 1935, with two coworkers, he published a paper on a newly created subject called later the EPR effect (EPR paradox). In this paper, starting from certain philosophical assumptions, on the basis of a rigorous analysis of a certain, complicated, but in the meantime assertedly realizable model, he came to the conclusion that quantum mechanics should be described as "incomplete". Niels Bohr asserted a refutation of Einstein's analysis immediately, and his view prevailed. After some decades, it was asserted that feasible experiments could prove the error of the EPR paper. These experiments tested the Bell inequalities published in 1964 in a purely theoretical paper. The above-mentioned EPR philosophical starting assumptions were considered to be falsified by the empirical fact (e.g. by the optical real experiments of Alain Aspect).
Thus thought experiments belong to a theoretical discipline, usually to theoretical physics, but often to theoretical philosophy. In any case, it must be distinguished from a real experiment, which belongs naturally to the experimental discipline and has "the final decision on true or not true", at least in physics.

=== Interactivity ===
Thought experiments can also be interactive where the author invites people into his thought process through providing alternative paths with alternative outcomes within the narrative, or through interaction with a programmed machine, like a computer program.
Thanks to the advent of the Internet, the digital space has lent itself as a new medium for a new kind of thought experiments. The philosophical work of Stefano Gualeni, for example, focuses on the use of virtual worlds to materialize thought experiments and to playfully negotiate philosophical ideas. His arguments were originally presented in his 2015 book Virtual Worlds as Philosophical Tools.
Gualeni's argument is that the history of philosophy has, until recently, merely been the history of written thought, and digital media can complement and enrich the limited and almost exclusively linguistic approach to philosophical thought. He considers virtual worlds (like those interactively encountered in videogames) to be philosophically viable and advantageous. This is especially the case in thought experiments, when the recipients of a certain philosophical notion or perspective are expected to objectively test and evaluate different possible courses of action, or in cases where they are confronted with interrogatives concerning non-actual or non-human phenomenologies.

== Examples ==

=== Humanities ===

=== Physics ===

=== Philosophy ===

=== Mathematics ===

=== Biology ===
Levinthal paradox
Rotating locomotion in living systems

=== Computer science ===

=== Economics ===
Broken window fallacy (law of unintended consequences, opportunity cost)
Laffer Curve

== See also ==

== Notes ==

== References ==

== Further reading ==

== Bibliography ==

== External links ==

Thought experiment at PhilPapers
Thought experiment at the Indiana Philosophy Ontology Project
Stevinus, Galileo, and Thought Experiments Short essay by S. Abbas Raza of 3 Quarks Daily
Thought experiment generator, a visual aid to running your own thought experiment