Online research in philosophy

In one of the most influential empiricist account on the epistemic nature of thought experiments John Norton proposes a challenge: that no thought experirnent in science could be found that cannot be logically reconstructed as an argument. Norton’s account has two main theses, the epistemic thesis that all information about the physical world delivered through a thought experiment comes solely frorn experience and the reconstruction thesis that all thought experiments could be reconstructed as arguments. In the present paper I argue that in at least sorne cases Norton’s theses are incompatible with each other and therefore their combination could not form a reliable account. I try to show that sometimes the experience available could not justify the conclusion of a thought experiment and even contradicts it. I suggest an analysis of Einstein’s Train Thought Experiment as a counterexample to the challenge.

Thought experiments are ordinary argumentation disguised in a vivid pictorial or narrative form. This account of their nature will allow me to show that empiricism has nothing to fear from thought experiments. They perform no epistemic magic. In so far as they tell us about the world, thought experiments draw upon what we already know of it, either explicitly or tacitly; they then transform that knowledge by disguised argumentation. They can do nothing more epistemically than can argumentation. I defend my account of thought experiments in Section 3 by urging that the epistemic reach of thought experiments turns out to coincide with that of argumentation and that this coincidence is best explained by the simple view that thought experiments just are arguments. Thought experiments can err—-a fact to be displayed by the thought experiment - anti thought experiment pairs of Section 2. Nonetheless thought experiments can be used reliably and, I urge in Section 4., this is only possible if they are governed by some very generalized logic. I will suggest on evolutionary considerations that their logics are most likely the familiar logics of induction and deduction, recovering the view that thought experiment is argumentation. Finally in Section 5 I defend this argument based epistemology of thought experiments against competing accounts. I suggest that these other accounts can offer a viable epistemology only insofar as they already incorporate the notion that thought experimentation is governed by a logic, possibly of very generalized form.

A characteristic of contemporary analytic philosophy is its ample use of thought experiments. We formulate two features that can lead one to suspect that a given thought experiment is a poor one. Although these features are especially in evidence within the philosophy of mind, they can, surprisingly enough, also be discerned in some celebrated scientific thought experiments. Yet in the latter case the consequences appear to be less disastrous. We conclude that the use of thought experiments is more successful in science than in philosophy.

The paper is a contribution to the debate on the epistemological status of thought experiments. I deal with the epistemological uniqueness of experiments in the sense of their irreducibility to other sources of justification. In particular, I criticize an influential argument for the irreducibility of thought experiments to general arguments. First, I introduce the radical empiricist theory of eliminativism, which considers thought experiments to be rhetorically modified arguments, uninteresting from the epistemological point of view. Second, I present objections to the theory, focusing on the critique of eliminativism by Tamar Szabó Gendler based on the reconstruction of famous Galileo's Pisa experiment. I show that her reconstruction is simplistic and that more elaborate reconstruction is needed for an appropriate assessment of the epistemic power of general argument. I propose such a reconstruction and demonstrate that general version of Pisa experiment is epistemically equal to the particular one. Thus, from an epistemological perspective, Galileo's thought experiment is reducible to a straightforward argument without particular premises.

An overview is provided of how the concept of the thought experiment has developed and changed for the natural sciences in the course of the 20th century. First, we discuss the existing definitions of the term 'thought experiment' and the origin of the thought experimentation method, identifying it in Greek Presocratics epoch. Second, only in the end of the 19th century showed up the first systematic enquiry on thought experiments by Ernst Mach's work. After the Mach's work, a negative attitude towards thought experiments came in the beginning of the 20th century, which went on until the Thomas Kuhn's and Karl Popper's work on thought experiments. Only from the mid-1980s did thought experiments begin to be considered relevant to scientific enterprise. Finally, we show the existing empirical and 'functional' theories which have developed about the nature and purpose of thought experiments.

I begin with an explication of "thought experiment". I then clarify the role that intuitions play in thought experiments by addressing two important issues: (1) the informativeness of thought experiments and (2) the legitimacy of the method of thought experiments in philosophy and the natural sciences. I defend a naturalistic account of intuitions that provides a plausible explanation of the informativeness of thought experiments, which, in turn, allows thought experiments to be reconstructed as arguments. I also specify criteria for distinguishing bad "intuition pumps" from legitimate thought experiments. These criteria help us to avoid being seduced by the dangerous suggestive power of misleading intuitions.

On the relation between experiment and thought experiment in the natural sciences. To understand the reciprocal autonomy and complementarity of thought and real experiment, it is necessary to distinguish between a ‘positive’ (empirical or formal) and a transcendental perspective. Empirically and formally, real and thought experiments are indistinguishable. However, from a reflexive-transcendental viewpoint thought experiment is at the same time irreducible and complementary to real experiment. This is due to the fact that the hypothetical-anticipatory moment is in principle irreducible to physical reality—even though it refers to physical reality and is bound with the empirical use of our understanding. The presence of counterfactuals is the condition of the possibility for thought experiments to become in principle real ones, by means of a series of technical realisations that gradually approximate the idealisations that they contain.

Commenting on Atkinson's paper I argue that leading to a successful real experiment is not the only scale on which a thought experiment's value is judged. Even the path from the original EPR thought experiment to Aspect's verification of the Bell inequalities was long-winded and involved considerable input from the sides of technology and mathematics. Von Neumann's construction of hidden variables was, moreover, a genuinely mathematical thought experiment that was successfully criticized by Bell. Such thought experiments are also possible in string theory, where any (non-trivial) empirical corroboration seems to be out of reach. Yet appraising mathematical thought experiments and their contribution to physical thought experiments requires a dynamical account which in the spirit of Mach and Lakatos attributes due weight to informal mathematical reasoning or empirical intuition.

Are thought experiments nothing but arguments? I argue that it is not possible to make sense of the historical trajectory of certain thought experiments if one takes them to be arguments. Einstein and Bohr disagreed about the outcome of the clock-in-the-box thought experiment, and so they reconstructed it using different arguments. This is to be expected whenever scientists disagree about a thought experiment's outcome. Since any such episode consists of two arguments but just one thought experiment, the thought experiment cannot be the arguments.

The operational perspective here defended permits a reflexive-transcendental point of view that sharply distinguishes the two concepts, while, at the same time, maintaining the connection between them. On the one hand, simply imagining that the experimental apparatus, counterfactually anticipated in a thought experiment, has really been constructed is sufficient to erase any difference between thought and real experiments. On the other hand, this very ‘imagining’, this capacity of the mind to assume every real entity as a possible entity, underpins the difference in principle – a properly transcendental difference – between thought and real experiments. This difference, however, implies the intimate association between experiment and thought experiment: All thought experiments must be thought of as translatable into real ones, and all real experiments as realisations of thought ones. What thought experiments have over and above real experiments is the mere fact that they exist in a purely hypothetical sphere; what real have over and above thought experiments is the mere fact that they overstep the sphere of the possible, in the experiment’s real execution.