This book offers a readable introduction to the main aspects of thought experimenting in philosophy and science. It presents the main options in understanding thought experiments, from empiricism to Platonism, and discusses their strengths and weaknesses. However, it also provides some original perspectives on the topic. Firstly, it provides a new definition and analysis of thought experimenting that brings it closer to laboratory experimenting. Secondly, it develops the author’s earlier theory of “mental modelling”, proposed some decades ago by him, and (...) some other researchers in the field as the crucial procedure in thought experimenting. The mental modelling approach links work with thought experimenting to cognitive science and to research on mental simulation which is a hot topic in present-day research. Thirdly, it proposes a principled way to respond to criticism of thought experimenting by “experimental philosophers” as they have been dominating the present-day debates. The response suggests a possible ameliorative, self-help project for thought experimenting. Finally, the book provides a way to systematize the history of important thought experiments in science and philosophy and thus connects, in an original way, the systematic investigation of experimenting to the historical work of famous thought experiments. It is of interest to scholars interested in history of ideas and philosophy of science. (shrink)

For many, the two key thinkers about science in the twentieth century are Thomas Kuhn and Karl Popper, and one of the key questions in contemplating science is how to make sense of theory change. In Creatively Undecided, philosopher Menachem Fisch defends a new way to make sense of the rationality of scientific revolutions. He argues, loosely following Kuhn, for a strong notion of the framework dependency of all scientific practice, while at the same time he shows how such frameworks (...) can be deemed the possible outcomes of keen rational deliberation along Popperian lines. Fisch's innovation is to call attention to the importance of ambiguity and indecision in scientific change and advancement. Specifically, he backs the problem up, looking not at how we might communicate rationally across an already existing divide but at the rational incentive to create an alternative framework in the first place. Creatively Undecided will be essential reading for philosophers of science, and its vivid case study in Victorian mathematics will draw in historians. (shrink)

Science relies on models and idealizations that are known not to be true. Even so, science is epistemically reputable. To accommodate science, epistemology should focus on understanding rather than knowledge and should recognize that the understanding of a topic need not be factive. This requires reconfiguring the norms of epistemic acceptability. If epistemology has the resources to accommodate science, it will also have the resources to show that art too advances understanding.

This work interprets the notion of thought experiment (TE) from the viewpoint of a functional reading of the a priori, that is, an a priori that is devoid of any particular content. It is true that Kant ascribes some content to the (synthetic) a priori, but only a functional reading of the a priori agrees with the spirit of Kant's philosophy and can be used for developing a consistent account of TEs. On the basis of this concept of the a (...) priori, an account is developed that mediates between Brown and Norton by considering TEs from two distinct but connected points of view: transcendental and operational. On the one hand, the account is transcendental in a very usual sense of the word: TEs are the condition of the possibility of real world experiments (REs) because, without the a priori capacity of the mind to reason counterfactually, we could not devise any hypothesis and would be unable to plan the corresponding RE that should test it. This capacity underpins the distinction in principle — a properly transcendental distinction — between TEs and REs. But while there is a distinction in principle between TE and RE on the transcendental level of the a priori capacity of the mind to reason counterfactually, the exclusively func¬tional character of the a priori entails that, on the operational-methodological level, TEs —considering their empirical content and actual performance within a discipline — are and function essentially like REs. (shrink)

In this paper I examine the role of thought experiments in the social studies of science. More specifically, I will focus on two strands of social studies of science: the so-called sociology of scientific knowledge and the naturalistically oriented philosophy of science with interest in social dimensions of science. I begin by discussing David Hull's views on thought experiments in the study of science. His account serves as a foil that helps me to make some points about thought experiments. As (...) an illustration I discuss two example of thought experimenting in the social studies of science. The first example is the use of thought experiments by the sociologists of scientific knowledge, and the second case will be the recent work by Philip Kitcher on division of cognitive labour. With the help of these cases, I argue that Hull's negative attitude towards the use of thought experiments requires some, tempering. The notion of thought experiment will be understood broadly in this paper. One could also talk about imaginary or hypothetical examples. In social sciences the contrast for thought experiments is not an experiment, but an empirical case study. Accordingly, thought experiment in social science in an imaginary case study or a made up historical scenario. The focus of my discussion is on the various functions and argumentative roles thought experiments have or could have in social studies of science. An empirical experiment (or a case study) is not an argument by itself, nor is a thought experiment. However, they both are used in making arguments and my aim is to look how they are used. (shrink)

The idea that claims about the physical world might be arrived through a priori reasoning has a long history in physics. But it is clear that empiricist notions of the nature of science, and in particular the empirical nature of physics, have held sway in this century. Yet, in the idea of thought experiments in science, we might find the survival of earlier a priori reasoning to the truth of claims about the physical world. This paper challenges the notion that (...) science can be understood as a purely empirical endeavor and points out what reforms would be necessary for teaching the image of science to our young. (shrink)

This paper develops an account of rigour in the use of thought experiments in ethics. I argue that there are two separate challenges to be faced. The first is internal validity: is the thought experiment designed in a way that allows its readers to make judgements that are confident and free of bias about the hypothesis or point of principle that it aims to test? The second is external validity: to what extent do ethical judgements that are correct of the (...) world of the thought experiment generalize to a wide variety of other contexts, including ethical decision-making in the actual world? Ensuring external validity is the harder and more important problem of rigour, yet it is one that few philosophers have even noticed, let alone begun to solve. (shrink)

A striking feature of the traditional armchair method of philosophy is the use of imaginary examples: for instance, of Gettier cases as counterexamples to the justified true belief analysis of knowledge. The use of such examples is often thought to involve some sort of a priori rational intuition, which crude rationalists regard as a virtue and crude empiricists as a vice. It is argued here that, on the contrary, what is involved is simply an application of our general cognitive capacity (...) to handle counterfactual conditionals, which is not exclusively a priori and is not usefully conceived as a form of rational intuition. It is explained how questions of metaphysical possibility and necessity are equivalent to questions about counterfactuals, and the epistemology of the former (in particular, the role of conceiving or imagining) is a special case of the epistemology of the latter. A non-imaginary Gettier case is presented in order to show how little difference it makes. (shrink)

Thought experiments have played a pivotal role in many debates within ethics—and in particular within applied ethics—over the past 30 years. Nonetheless, despite their having become a commonly used philosophical tool, there is something odd about the extensive reliance upon thought experiments in areas of philosophy, such as applied ethics, that are so obviously oriented towards practical life. Herein I provide a moderate defence of their use in applied philosophy against those three objections. I do not defend all possible uses (...) of thought experiments but suggest that we should distinguish between legitimate and illegitimate uses. Their legitimate uses are determined not so much by the modal content of any actual thought experiment itself, but by the extent to which the argument in which it is nested follows basic tenets of informal logic and respects the fundamental contingency of applied ethical problems. In pursuing these ideas, I do not so much provide a set of criteria for their legitimate use, but more modestly present two significant ways in which their use can go awry. (shrink)

Recent years saw the rise of an interest in the roles and significance of thought experiments in different areas of human thinking. Heisenberg's gamma ray microscope is no doubt one of the most famous examples of a thought experiment in physics. Nevertheless, this particular thought experiment has not received much detailed attention in the philosophical literature on thought experiments up to date, maybe because of its often claimed inadequacies. In this paper, I try to do two things: to provide an (...) interesting interpretation of the roles played by Heisenberg's gamma ray microscope in interpreting quantum mechanics – partly based on Thomas Kuhn’s views on the function of thought experiments – and to contribute to the ongoing discussions on the roles and significance of thought experiments in physics. (shrink)

Many important metaphysical arguments validly deduce an actuality from a possibility. For example: Because it is possible for me to exist in the absence of anything material, I am not my body. I argue that there is no reason to suppose that our capacity for modal judgment is equal to the task of determining whether the "possibility" premise of any of these arguments is true. I connect this thesis with Stephen Yablo's recent work on the epistemology of modal statements.

Most papers in theoretical economics contain thought experiments. They take the form of more informal bits of reasoning that precede the presentation of the formal, mathematical models these papers are known for. These thought experiments differ from the formal models in various ways. In particular, they do not invoke the same idealized assumptions about the rationality, knowledge, and preferences of agents. The presence of thought experiments in papers that present formal models, and the fact that they differ from the formal (...) models in this way, is often ignored in debates on what, if anything, we can learn from formal models in theoretical economics. I show that paying due attention to thought experiments in theoretical economics has serious implications for this debate. Differences between thought experiments and formal models are especially problematic for Robert Sugden’s “credible worlds” account. (shrink)

Thought experiments have been influential in philosophy at least since Plato, and they have contributed to science at least since Galileo. Some of this influence is appropriate, because thought experiments can have legitimate roles in generating and clarifying hypotheses, as well as in identifying problems in competing hypotheses. I will argue, however, that philosophers have often overestimated the significance of thought experiments by supposing that they can provide evidence that supports the acceptance of beliefs. Accepting hypotheses merely on the basis (...) of thinking about them constitutes a kind of epistemic hubris with many negative consequences, including the acquisition of false beliefs and the blocking of .. (shrink)

I claim that one way thought experiments contribute to scientific progress is by increasing scientific understanding. Understanding does not have a currently accepted characterization in the philosophical literature, but I argue that we already have ways to test for it. For instance, current pedagogical practice often requires that students demonstrate being in either or both of the following two states: 1) Having grasped the meaning of some relevant theory, concept, law or model, 2) Being able to apply that theory, concept, (...) law or model fruitfully to new instances. Three thought experiments are presented which have been important historically in helping us pass these tests, and two others that cause us to fail. Then I use this operationalization of understanding to clarify the relationships between scientific thought experiments, the understanding they produce, and the progress they enable. I conclude that while no specific instance of understanding (thus conceived) is necessary for scientific progress, understanding in general is. (shrink)

Sometimes we learn through the use of imagination. The epistemology of imagination asks how this is possible. One barrier to progress on this question has been a lack of agreement on how to characterize imagination; for example, is imagination a mental state, ability, character trait, or cognitive process? This paper argues that we should characterize imagination as a cognitive ability, exercises of which are cognitive processes. Following dual process theories of cognition developed in cognitive science, the set of imaginative processes (...) is then divided into two kinds: one that is unconscious, uncontrolled, and effortless, and another that is conscious, controlled, and effortful. This paper outlines the different epistemological strengths and weaknesses of the two kinds of imaginative process, and argues that a dual process model of imagination helpfully resolves or clarifies issues in the epistemology of imagination and the closely related epistemology of thought experiments. (shrink)

John D. Norton defends an empiricist epistemology of thought experiments, the central thesis of which is that thought experiments are nothing more than arguments. Philosophers have attempted to provide counterexamples to this claim, but they haven’t convinced Norton. I will point out a more fundamental reason for reformulation that criticizes Norton’s claim that a thought experiment is a good one when its underlying logical form possesses certain desirable properties. I argue that by Norton’s empiricist standards, no thought experiment is ever (...) justified in any deep sense due to the properties of its logical form. Instead, empiricists should consider again the merits of evaluating thought experiments more like laboratory experiments, and less like arguments. (shrink)

Arguments from thought experiment ask the reader to imagine some hypothetical, sometimes exotic, often fantastic, scenario for the sake of illustrating or countering some claim. Variously characterized as mental experimentation, imaginary cases, and even crazy cases, thought experiments figure into both scientific and philosophical arguments. They are often criticized for their fictive nature and for their lack of grounding. Nevertheless, they are common especially in arguments in ethics and philosophy of mind. Moreover, many thought experiments have spawned variations that attempt (...) to both affirm and refute their original arguments. These emended thought experiments exhibit a variety of styles, details, and embellishments. A rhetorical analysis of these variations suggests a reciprocal influence between the arguers' selection of details and their philosophical commitments. I offer examples of this relationship from the variations on John Searle's Chinese Room thought experiment and Judith Thomson's unconscious violinist thought experiment. (shrink)

Thought experiments in the history of science display a striking asymmetry between chemistry and physics, namely that chemistry seems to lack well-known examples, whereas physics presents many famous examples. This asymmetry, I argue, is not independent data concerning the chemistry/physics distinction. The laws of chemistry such as the periodic table are incurably special, in that they make testable predictions only for a very restricted range of physical conditions in the universe which are necessarily conditioned by the contingences of chemical investigation. (...) The argument depends on how ‚thought experiment’ is construed. Here, several recent accounts of thought experiments are surveyed to help formulate what I call ‚crucial’ thought experiments. These have a historical role in helping to judge between hypotheses in physics, but are not helpful in chemistry past or present. (shrink)

Examples from Archimedes, Galileo, Newton, Einstein, and others suggest that fundamental laws of physics were—or, at least, could have been—discovered by experiments performed not in the physical world but only in the mind. Although problematic for a strict empiricist, the evolutionary emergence in humans of deeply internalized implicit knowledge of abstract principles of transformation and symmetry may have been crucial for humankind's step to rationality—including the discovery of universal principles of mathematics, physics, ethics, and an account of free will that (...) is compatible with determinism. (shrink)

According to popular opinion, thought experiments are limited in scope, since no novel empirical results could be expected to be produced by thought alone. Yet consider the spectacular 16th century experiment by Stevin. leading to the discovery of the principles of the resolution and combination of forces. He conducted no experiments, for he derived his novel and highly important conclusions by several steps of ingenious reasoning alone. To understand why mental experiments may serve as very effective scientific tools. we need (...) to explicate carefully their underlying mechanism. Thought experiments invariably involve the widely debated notion of “counterfactual conditionals.” A variety of historical examples are offered designed to illustrate the nature of thought experiments, their associated counterfactual conditionals. as well a the nature of the vital link between the two. (shrink)

This essay proposes an alternative way of studying video games: as thought experiments akin to the narrative thought experiments that are frequently used in philosophy. This perspective incorporates insights from the narratological and ludological perspectives in game studies and highlights the philosophical significance of games. Video game thought experiments are similar to narrative thought experiments in many respects and can perform the same functions. They also have distinctive advantages over narrative thought experiments, as they situate counterfactuals in more complex, developed (...) contexts and present them to players who are participants in game worlds, rather than simply observers. (shrink)

It has been pointed out that Gettier case scenarios have deviant realizations and that deviant realizations raise a difficulty for the logical analysis of thought experiments. Grundmann and Horvath have shown that it is possible to rule out deviant realizations by suitably modifying the scenario of a Gettier-style thought experiment. They hypothesize further that the enriched scenario corresponds to the way expert epistemologists implicitly interpret the original one. However, no precise account of this implicit enrichment is offered, which makes the (...) proposal somewhat ad hoc. Drawing on pragmatic theory, I argue that the content of Grundmann and Horvath’s modified scenario corresponds to the default interpretation of the original scenario and that epistemological expertise is not required to access the deviance-proof interpretation. This Default Interpretation proposal offers thus a more general and independently motivated solution to the Problem of Deviant Realizations. (shrink)

Where should computer simulations be located on the ‘usual methodological map’ which distinguishes experiment from theory? Specifically, do simulations ultimately qualify as experiments or as thought experiments? Ever since Galison raised that question, a passionate debate has developed, pushing many issues to the forefront of discussions concerning the epistemology and methodology of computer simulation. This review article illuminates the positions in that debate, evaluates the discourse and gives an outlook on questions that have not yet been addressed.

Thought experiments are usually employed by philosophers as a tool in conceptual analysis. We pose ourselves questions such as “Would it be the same F if p?” or “Would it count as knowledge if q,” where p and q state some bizarre circumstances that are unlikely actually to occur and may even be beyond current technical possibility. The answers we are inclined to give to such questions are held to throw light on the nature of our concepts of, in these (...) cases, identity and knowledge. But the facts about our concepts that are unearthed in this way are implicitly assumed to be deep, not superficial, facts. They are not meant to be facts contingent upon our current linguistic usage, psychology, or social structure, where these could easily be otherwise. If they were just facts of this superficial kind, it would hardly be worth the effort of uncovering them, for they would bind no-one who preferred a different convention or practice. The conceptual truths revealed are meant to be unavoidable, in some sense, and not merely conventional: there is something Platonic or Kantian in the background. The argument of Sections 2–8 of this essay is that, in the case of the thought experiments used to throw light on our concepts of person and personal identity, the results do not seem to be deep or hard to revise, and that this is so largely because of the ontological assumptions shared by more or less all participants in the debate. I shall be arguing that it is primarily these ontological assumptions, rather than the insight into our concepts that the thought experiments are supposed to bring, that determine the answers to the questions about persons and their identity. In the final two sections I shall make some cautious qualifications to this conclusion. (shrink)

Thought experiments are ubiquitous in science and especially prominent in domains in which experimental and observational evidence is scarce. One such domain is the causal analysis of singular events in history. A long‐standing tradition that goes back to Max Weber addresses the issue by means of ‘what‐if’ counterfactuals. In this paper I give a descriptive account of this widely used method and argue that historians following it examine difference makers rather than causes in the philosopher’s sense. While difference making is (...) neither necessary nor sufficient for causation, to establish difference makers is more consistent with the historians’ more ultimate purposes. †To contact the author, please write to: Department of Philosophy, Erasmus University, 3000 DR Rotterdam, The Netherlands; e‐mail: [email protected]. (shrink)

The growing literature on philosophical thought experiments has so far focused almost exclusively on the role of thought experiments in confirming or refuting philosophical hypotheses or theories. In this paper we draw attention to an additional and largely ignored role that thought experiments frequently play in our philosophical practice: some thought experiments do not merely serve as means for testing various philosophical hypotheses or theories, but also serve as facilitators for conceiving and articulating new ones. As we will put it, (...) they serve as ‘heuristics for theory discovery’. Our purpose in the paper is two-fold: to make a case that this additional role of thought experiments deserves the attention of philosophers interested in the methodology of philosophy; to sketch a tentative taxonomy of a number of distinct ways in which philosophical thought experiments can aid theory discovery, which can guide future research on this role of thought experiments. (shrink)

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. (shrink)

We have never entirely agreed with Daniel Cohnitz on the status and rôle of thought experiments. Several years ago, enjoying a splendid lunch together in the city of Ghent, we cheerfully agreed to disagree on the matter; and now that Cohnitz has published his considered opinion of our views, we are glad that we have the opportunity to write a rejoinder and to explicate some of our disagreements. We choose not to deal here with all the issues that Cohnitz raises, (...) but rather to restrict ourselves to three specific points. (shrink)

Still today it remains unclear whether Galileo ever climbed the leaning tower of Pisa in order to drop bodies from its top. Some believe that he established the principle of equal speeds for falling bodies by means of an ingenious thought experiment. However, the reconstruction of that thought experiment circulating in the philosophical literature is no more than a cartoon. In this paper I will tell the story of the thought processes behind the cartoon.Keywords: Galileo Galilei; Thought experiment; Falling bodies.

Newton’s equations of motion tell us that a mass at rest at the apex of a dome with the shape specified here can spontaneously move. It has been suggested that this indeterminism should be discounted since it draws on an incomplete rendering of Newtonian physics, or it is “unphysical,” or it employs illicit idealizations. I analyze and reject each of these reasons. †To contact the author, please write to: Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, PA (...) 15260; e‐mail: [email protected]. (shrink)

Thought experiments in science are merely picturesque argumentation. I support this view in various ways, including the claim that it follows from the fact that thought experiments can err but can still be used reliably. The view is defended against alternatives proposed by my cosymposiasts.

Canadian Journal of Philosophy, 26, pp. 333-66. 1996.

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. (shrink)

The paper presents an argument for treating certain types of computer simulation as having the same epistemic status as experimental measurement. While this may seem a rather counterintuitive view it becomes less so when one looks carefully at the role that models play in experimental activity, particularly measurement. I begin by discussing how models function as “measuring instruments” and go on to examine the ways in which simulation can be said to constitute an experimental activity. By focussing on the connections (...) between models and their various functions, simulation and experiment one can begin to see similarities in the practices associated with each type of activity. Establishing the connections between simulation and particular types of modelling strategies and highlighting the ways in which those strategies are essential features of experimentation allows us to clarify the contexts in which we can legitimately call computer simulation a form of experimental measurement. (shrink)

Novels and thought experiments can be pathways to different kinds of knowledge. We may, however, be hard pressed to say exactly what can be learned from novels but not from thought experiments. Headway on this matter can be made by spelling out their respective conditions for epistemic failure. Thought experiments fail in their epistemic role when they neither yield propositional knowledge nor contribute to an argument. They are largely in the business of ‘knowing that’. Novels, on the other hand can (...) be an epistemic success by yielding ‘knowledge how’. They can help us to improve our competences. (shrink)

Explaining intuitions in terms of “facts of our natural history” is compatible with rationally trusting them. This compatibilist view is defended in the present paper, focusing upon nomic and essentialist modal intuitions. The opposite, incompatibilist view alleges the following: If basic modal intuitions are due to our cognitive make‐up or “imaginative habits” then the epistemologists are left with a mere non‐rational feeling of compulsion on the side of the thinker. Intuitions then cannot inform us about modal reality. In contrast, the (...) paper argues that there are several independent sources of justification which make the feeling of compulsion rational: the prima‐facie and a priori ones come from the obviousness of our basic modal intuitions and our not being able to imagine things otherwise, others, a posteriori, from the epistemic success of these intuitions. Further, the general scheme of evolutionary learning is reliable, reliability is preserved in the resulting individual's cognitive make‐up, and we can come to know this a posteriori. The a posteriori appeal to evolution thus plays a subsidiary role in justification, filling the remaining gap and removing the residual doubt. Explaining modal intuitions is compatible with moderate realism about modality itself. (shrink)

This paper motivates, explains, and defends a new account of the content of thought experiments. I begin by briefly surveying and critiquing three influential accounts of thought experiments: James Robert Brown’s Platonist account, John Norton’s deflationist account that treats them as picturesque arguments, and a cluster of views that I group together as mental model accounts. I use this analysis to motivate a set of six desiderata for a new approach. I propose that we treat thought experiments primarily as aesthetic (...) objects, specifically fictions, and then use this analysis to characterize their content and ultimately assess their epistemic success. Taking my starting point from Kendall Walton’s account of representation (Mimesis as make-believe, Harvard University Press, Cambridge, 1990), I argue that the best way to understand the content of thought experiments is to treat them as props for imagining fictional worlds. Ultimately, I maintain that, in terms of their form and content, thought experiments share more with literary fictions and pictorial representations than with either argumentation or observations of the Platonic realm. Moreover, while they inspire imaginings, thought experiments themselves are not mental kinds. My approach redirects attention towards what fixes the content of any given thought experiment and scrutinizes the assumptions, cognitive capacities and conventions that generate them. This view helps to explain what seems plausible about Brown’s, Norton’s, and the mental modelers’ views. (shrink)

Thought experiment acquires evidential significance only on particular metaphysical assumptions. These include the thesis that science aims at uncovering "phenomena"universal and stable modes in which the world is articulatedand the thesis that phenomena are revealed imperfectly in actual occurrences. Only on these Platonically inspired assumptions does it make sense to bypass experience of actual occurrences and perform thought experiments. These assumptions are taken to hold in classical physics and other disciplines, but not in sciences that emphasize variety and contingency, such (...) as Aristotelian natural philosophy and some forms of historiography. This explains why thought experiments carry weight in the former but not the latter disciplines. (shrink)