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)

I introduce a middle route between giving a sharp definition and examples to explain what a thought experiment is. It comprises an account of the concept thought experiment that we can rightly apply to different extents. Three explanatory virtues of this account include (i) that we can use it to explain why one thing may seem to be less of a thought experiment than another, (ii) that it provides for a fine-grained explanation of the relation between literary fiction and thought (...) experiment and (iii) that we can use it to explain conflicting intuitions about whether certain literary fictions are thought experiments. (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)

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)

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)

In economics, thought experiments are frequently justified by the difficulty of conducting controlled experiments. They serve several functions, such as establishing causal facts, isolating tendencies, and allowing inferences from models to reality. In this paper, I argue that thought experiments served a further function in economics: facilitating the quantitative definition and measurement of the theoretical concept of utility, thereby bridging the gap between theory and statistical data. I support my argument by a case study, the “hypothetical experiments” of the Norwegian (...) economist Ragnar Frisch (1895-1973). Frisch aimed to eliminate introspection and a subjective concept of utility from economic reasoning. At the same time, he sought behavioral foundations for economic theory that enabled quantitative reasoning. By using thought experiments to justify his set of choice axioms and facilitating the operationalization of utility, Frisch circumvented the problem of observing utility via actual experiments without eliminating the concept of utility from economic theory altogether. As such, these experiments helped Frisch to empirically support the theory’s most important results, such as the laws of demand and supply, without the input of new empirical findings. I suggest that Frisch’s experiments fulfill the main characteristics of thought experiments. (shrink)

This is the introduction to the Routledge Companion to Thought Experiments.

I wish to explore the idea that thought experiments are best accounted for as a special case of a narrative that features an interplay between puzzles and paradoxes. Furthermore, I believe the more successfully thought experiments manage to combine puzzles and paradoxes the more insightful and instructive they become. I suggest the latter kind of thought experiments also use the technique of mental variation.

Much of the recent movement organized under the heading “Experimental Philosophy” has been concerned with the empirical study of responses to thought experiments drawn from the literature on philosophical analysis. I consider what bearing these studies have on the traditional projects in which thought experiments have been used in philosophy. This will help to answer the question what the relation is between Experimental Philosophy and philosophy, whether it is an “exciting new style of [philosophical] research”, “a new interdisciplinary field that (...) uses methods normally associated with psychology to investigate questions normally associated with philosophy” (Knobe et al. 2012), or whether its relation to philosophy consists, as some have suggested, in no more than the word ‘philosophy’ appearing in its title, or whether the truth lies somewhere in between these two views. I first distinguishes different strands in Experimental Philosophy, negative and positive x-phi, and x-phi pursuing philosophy as opposed to x-phi as cognitive science. Next I review some ways in which Experimental Philosophy has been criticized. Finally, I consider what would have to be true for Experimental Philosophy to have one or another sort of relevance to philosophy, whether the assumptions required are true, how we could know it, and the ideal limits of the usefulness Experimental Philosophy to philosophy. I conclude x-phi cannot in principle be a replacement for traditional first person approaches because it yields the wrong kind of knowledge and that it can nonetheless be a practical aid in conducting philosophical thought experiments. n. (shrink)

The conventional interpretation that Pierre Duhem condemned outright any type of thought experiment in Ernst Mach’s sense should be, at least in large part, rejected. Although Duhem placed particular emphasis on the perils of thought experiments that Mach had overlooked or at least underestimated, he retained the core idea of Mach’s theory, according to which thought experiments cannot break free from the ultimate authority of real-world experiments. This similarity between Duhem’s and Mach’s views about thought experiments is not the only (...) one. Just as there was in Duhem’s criticism of “expériences fictives” a tendency leading him to give voice to one of Mach’s basic empiricist claims, so also there was in Mach’s interpretation of thought experiments a tendency in the direction of Duhem’s conventionalism. If Mach’s and Duhem’s conceptions of thought experiments are compared, there results an importantly similar, although not identical, tension that should properly be taken into account in the more general comparison between Mach and Duhem. (shrink)

We might think that thought experiments are at their most powerful or most interesting when they produce new knowledge. This would be a mistake; thought experiments that seek understanding are just as powerful and interesting, and perhaps even more so. A growing number of epistemologists are emphasizing the importance of understanding for epistemology, arguing that it should supplant knowledge as the central notion. In this chapter, I bring the literature on understanding in epistemology to bear on explicating the different ways (...) that thought experiments increase three important kinds of understanding: explanatory, objectual and practical. (shrink)

What role does the imagination play in scientific progress? After examining several studies in cognitive science, I argue that one thing the imagination does is help to increase scientific understanding, which is itself indispensable for scientific progress. Then, I sketch a transcendental justification of the role of imagination in this process.

: This article seeks to explain how thought experiments work, and also the reasons why they can fail. It is divided into four sections. The first argues that thought experiments in philosophy and science should be treated together. The second examines existing accounts of thought experiments and shows why they are inadequate. The third proposes a better account of thought experiments. According to this account, a thought experimenter manipulates her worldview in accord with the “what if” questions posed by a (...) thought experiment. When all necessary manipulations are carried through, the result is either a consistent model or a contradiction. If a consistent model is achieved, the thought experimenter can conclude that the scenario is possible; if a consistent model cannot be constructed, then the scenario is not possible. The fourth section of the article uses this account to shed light on the circumstances in which thought experiments fail. (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)

Wie ist es wohl, eine Fledermaus zu sein? Wäre ein rein physikalisches Duplikat von mir nur ein empfindungsloser Zombie? Muss man sich seinem Schicksal ergeben, wenn man sich unfreiwillig als lebensnotwendige Blutwaschanlage eines weltberühmten Violinisten wieder findet? Kann man sich wünschen, der König von China zu sein? Bin ich vielleicht nur ein Gehirn in einem Tank mit Nährflüssigkeit, das die Welt von einer Computersimulation vorgegaukelt bekommt? Worauf beziehen sich die Menschen auf der Zwillingserde mit ihrem Wort 'Wasser', wenn es bei (...) ihnen gar kein H2O gibt? -/- Diese und weitere seltsame Fragen sind das tägliche Brot vieler professioneller Philosophen. Die abstrusen Umstände, die dabei geschildert werden, nennt man "Gedankenexperimente". -/- Was soll die Erörterung dieser Szenarien, die sich so weit von unserem alltäglichen Leben, z.T. außerhalb der Grenzen unserer Wirklichkeit abspielen? Welche Rolle spielen diese "Gedankenexperimente" in der philosophischen Methodologie? Ist diese Rolle überhaupt berechtigt? -/- Das vorliegende Buch gibt Antworten auf diese Fragen. Es stellt sich heraus, dass diese seltsamen Gedankenexperimente nicht nur berechtigte, sondern überaus wichtige Instrumente philosophischen Forschens darstellen. (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)

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. (shrink)

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 second volume in the _Blackwell Brown Lectures in Philosophy_, this volume offers an original and provocative take on the nature and methodology of philosophy. Based on public lectures at Brown University, given by the pre-eminent philosopher, Timothy Williamson Rejects the ideology of the 'linguistic turn', the most distinctive trend of 20th century philosophy Explains the method of philosophy as a development from non-philosophical ways of thinking Suggests new ways of understanding what contemporary and past philosophers are doing.

Nicholas Rescher surveys and analyzes the different kinds of unreal possibilities and nonexistent objects, tying together all the diverse ways in which this area has been approached by philosophers. As he surveys the field and clarifies the kinds of unreality, he also makes a sustained argument against the philosophical fashion for dealing with nonexistent possible world as though they were authentic objects. The author holds that, while we may discuss possibilities, we ought not to accord them ontological status. The possibility (...) of existence of a certain sort of world is not the existence of possible world of a certain sort. While we may reasonable discuss possibilities at the generic level, such as a world where dogs have horns, this does not require a commitment to a possible world where they do. The work that theorists of logic and language want to accomplish with possible worlds and individuals can be managed with propositional manifolds, stories or scenarios, while the modalities of necessity and possibility that modal logicians want to analyze in terms of realization in possible worlds can be handled by turning instead to figuring in stories or scenarios. (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)

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)

Why should a thought experiment, an experiment that only exists in people's minds, alter our fundamental beliefs about reality? After all, isn't reasoning from the imaginary to the real a sign of psychosis? A historical survey of how thought experiments have shaped our physical laws might lead one to believe that it's not the case that the laws of physics lie - it's that they don't even pretend to tell the truth. My aim in this paper is to defend an (...) account of thought experiments that fits smoothly into our understanding of the historical trajectory of actual thought experiments and that explains how any rational person could allow an imagined, unrealized (or unrealizable) situation to change their conception of the universe. (shrink)

Paul Thagard has recently argued that thought experiments are dangerous and misleading when we try to use them as evidence for claims. This paper refutes his skepticism. Building on Thagard’s own work in cognitive science, I suggest that Thagard has much that is positive to say about how thought experiments work. My last section presents some new directions for research on the intersection between thought experiments and cognitive science.

. What are thought experiments, and how do they generate knowledge? More specifically, what sorts of intentional acts must one perform in order to carry out a thought experiment, what sorts of objects are such acts directed toward, and how are those objects made present in such acts? I argue on phenomenological grounds that the proper objects of thought experiments are, in certain cases, uninstantiated universals and relations among them. I will also argue that, in the best of cases, we (...) intuit or “see” these universals and their relations to one another, and respond to some objections to this view. (shrink)

This paper presents a critical analysis of Tamar Szabó Gendler’s view of thought experiments, with the aim of developing further a constructivist epistemology of thought experiments in science. While the execution of a thought experiment cannot be reduced to standard forms of inductive and deductive inference, in the process of working though a thought experiment, a logical argument does emerge and take shape. Taking Gendler’s work as a point of departure, I argue that performing a thought experiment involves a process (...) of self-interrogation, in which we are compelled to reflect on our pre-existing knowledge of the world. In doing so, we are forced to make judgments about what assumptions we see as relevant and how they apply to an imaginary scenario. This brings to light the extent to which certain forms of skill, beyond the ability to make valid logical inferences, are necessary to execute a thought experiment well. (shrink)

Several major breakthroughs in the history of physics have been prompted not by new empirical data but by thought experiments. James Robert Brown and John Norton have developed accounts of how thought experiments can yield such advances. Brown argues that knowledge gained via thought experiments demands a Platonic explanation; thought experiments for Brown are a window into the Platonic realm of the laws of nature. Norton argues that thought experiments are just cleverly disguised inductive or deductive arguments, so no new (...) account of their epistemology is needed. In this paper, I argue that although we do not need to invoke any Platonic insight to explain thought experimentation, Norton’s eliminativist account fails to capture the unique epistemological importance of thought experiments qua thought experiments. I then present my own account, according to which thought experiments are a particular type of inductive inference that is uniquely suited to generate new breakthroughs. (shrink)

Ein Gespenst geht um in den Wissenschaften - das Gespenst des Gedankenexperiments. Gedankenexperimente verheißen Erkenntnisgewinn ohne empirische Arbeit - was vor dem Selbstverständnis der modernen Naturwissenschaften jedoch einer Unmöglichkeit gleichkommt. Und doch zieht sich das Forschen mit Gedankenexperimenten wie ein roter Faden durch die lange Tradition in den empirischen Wissenschaften von ihren Anfängen bei Stevin, Galilei und Newton bis heute.

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)

Marco Buzzoni has presented a Kantian account of thought experiments in science as a serious rival to the current empiricist and Platonic accounts. This paper takes the first steps of a comprehensive assessment of this account in order to further the more general discussion of the feasibility of a Kantian theory of scientific thought experiments. Such a discussion is overdue. To this effect the broader question is addressed as to what motivates a Kantian approach. Buzzoni's account and the assessment developed (...) in this paper are warranted by the fact that the history of philosophical inquiry into thought experiments is deeply interwoven with Kant's philosophy. This history will be depicted here for the first time in more comprehensive terms to contextualize Buzzoni's account in historical and systematic perspective. (shrink)

An explorative contribution to the ongoing discussion of thought experiments. While endorsing the majority view that skepticism about thought experiments is not well justified, in what follows we attempt to show that there is a kind of “bodiliness” missing from current accounts of thought experiments. That is, we suggest a phenomenological addition to the literature. First, we contextualize our claim that the importance of the body in thought experiments has been widely underestimated. Then we discuss David Gooding's work, which contains (...) the only explicit recognition of the importance of the body to understanding thought experiments. Finally, we introduce a phenomenological perspective of the body, which will give us the opportunity to sketch the power and promise of a phenomenological approach to thought experiments. (shrink)

I consider how we might begin to redress a cognitive model for thought experimental and other imagery-based scientific reasoning from an embodied cognition viewpoint. The paper gravitates on clarifying tour issues: (i) the danger of understanding the genuine novelty of thought-experimental reasoning and other imagery-based reasoning as a product of ‘quasi-perceiving’ new phenomenology with the ‘mind’s eye’ (as asserted by quasi-pictorialist theories of imagery); (ii) the erroneous choice of units of analysis that assume equivalence of external reports of visual imagery (...) with those internal structures that govern imagery-based reasoning, which are, as I will argue, largely linked to motor processes; (iii) the establishment of thought experimentation as imagery-based reasoning by providing evidence for the psychological necessity of imagistic simulation in thought experiments; (iv) a cognitive model for how learning via thought experimentation and other imagery-based reasoning takes place. The study was underpinned by constructivist assumptions. Case methodology was adopted, the case being a pair of final year A-level physics students. Data was collected through non-participant observation over two sessions of collaborative problem-solving. The tasks drew upon Newtonian mechanics. (shrink)

Thought experiments being central to contemporary philosophy and science, the following questions were asked in recent literature. What is their definition? Are they heuristic devices, arguments, paradoxes? Are they comparable to real experiments? Do intuition and conceivability intervene? Equally imaginative thought experiments are found in ancient, medieval, and Renaissance texts. Paying attention to prime historical examples of thought experiments, we show that historical perspectives help answer these general questions.

: While thought experiments play an important role in contemporary analytic philosophy, much remains unclear about thought experiments. In particular, it is still unclear whether the judgments elicited by thought experiments can provide evidence for the premises of philosophical arguments. This article argues that, if an influential and promising view about the nature of the judgments elicited by thought experiments is correct, then many thought experiments in philosophy fail to provide any evidence for the premises of philosophical arguments.

It is commonly held that our intuitive judgements about imaginary problem cases are justified a priori, if and when they are justified at all. In this paper I defend this view — ‘rationalism’ — against a recent objection by Timothy Williamson. I argue that his objection fails on multiple grounds, but the reasons why it fails are instructive. Williamson argues from a claim about the semantics of intuitive judgements, to a claim about their psychological underpinnings, to the denial of rationalism. (...) I argue that the psychological claim — that a capacity for mental simulation explains our intuitive judgements — does not, even if true, provide reasons to reject rationalism. (More generally, a simulation hypothesis, about any category of judgements, is very limited in its epistemological implications: it is pitched at a level of explanation that is insensitive to central epistemic distinctions.) I also argue that Williamson’s semantic claim — that intuitive judgements are judgements of counterfactuals — is mistaken; rather, I propose, they are a certain kind of metaphysical possibility judgement. Several other competing proposals are also examined and criticized. (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)

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)

Let's begin with an old example. In De Rerum Naturua , Lucretius presented a thought experiment to show that space is infinite. We imagine ourselves near the alleged edge of space; we throw a spear; we see it either sail through the ‘edge’ or we see it bounce back. In the former case the ‘edge’ isn't the edge, after all. In the latter case, there must be something beyond the ‘edge’ that repelled the spear. Either way, the ‘edge’ isn't really (...) an edge of space, after all. So space is infinite. (shrink)

In his paper ‘A Function for Thought Experiments’, T. S. Kuhn asks: Ought we demand of our concepts, as we do of our laws and theories, that they be applicable to any and every situation that might conceivably arise in any possible world? Is it not sufficient to demand of a concept, as we do of a law or theory, that it be unequivocally applicable in every situation which we expect ever to encounter?

When they abandoned the analytic-synthetic distinction, analytic philosophers substituted for it uncritical appeals to thought experiments or conceivability arguments. Although the history of philosophy is replete with thought experiments, medieval and early modern philosophers developed sophisticated theories concerning what governs what happens in thought experiments. By contrast, contemporary philosophers subscribe to the thesis of facile conception according to which casual allegations of conceivability or inconceivability are taken as good evidence of possibility or impossibility. Philosophers need to adopt standards of thought (...) experimentation like those found in science and to ground them in a general theory of conceivability. (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.