Thought Experiments

Can merely thinking about an imaginary situation provide evidence for how the world actually is--or how it ought to be? In this lively book, Roy A. Sorensen addresses this question with an analysis of a wide variety of thought experiments ranging from aesthetics to zoology. Presenting the first general theory of thought experiment, he sets it within an evolutionary framework and integrates recent advances in experimental psychology and the history of science, with special emphasis on Ernst Mach and Thomas Kuhn. (...) Sorensen explores what thought experiments are, how they work, and what their virtues and vices are. In his view, philosophy differs from science in degree, but not in kind. For this reason, he claims, it is possible to understand philosophical thought experiments by concentrating on their resemblance to scientific relatives. Sorensen assesses the hazards of thought experiments and grants that there are interesting ways in which the method leads us astray, but attacks most scepticism about thought experiments as arbitrary. He maintains that they should be used--as they generally are--as part of a diversified portfolio of techniques, creating a network of cross-checks that make for impressive reliability. (shrink)

In 1969 Harry Frankfurt published his hugely influential paper 'Alternate Possibilities and Moral Responsibility' in which he claimed to present a counterexample to the so-called 'Principle of Alternate Possibilities' ('a person is morally responsible for what he has done only if he could have done otherwise'). The success of Frankfurt-style cases as counterexamples to the Principle has been much debated since. I present an objection to these cases that, in questioning their conceptual cogency, undercuts many of those debates. Such cases (...) all require a counterfactual mechanism that could cause an agent to perform an action that he cannot avoid performing. I argue that, given our concept of what it is for someone to act, this requirement is inconsistent. Frankfurt-style alleged counterexamples are cases where an agent is morally responsible for an action he performs even though, the claim goes, he could not have avoided performing that action. However, it has recently been argued, e.g. by John Fischer, that a counterexample to the Principle could be a 'Fischer-style case', i.e. a case where the agent can either perform the action or do nothing else. I argue that, although Fischer-style cases do not share the conceptual flaw common to all Frankfurt-style cases, they also fail as counterexamples to the Principle. The paper finishes with a brief discussion of the significance of the Principle of Alternate Possibilities. (shrink)

Argumentative thought experiments are structurally conditional clauses. They can hence be formalized by means of the principle of modus ponendo ponens, as well as of modus tollendo tollens. In contrast to the practice in formal logic, exponents of argumentative thought experiments claim that the logical validity of a conclusion drawn within the framework of a particular conditional argument also holds beyond the particular conditional in question. In this paper, I articulate the criticism that this claim is wrong by arguing that (...) the counterfactual scenario sets itself the most determinant premise. If the counterfactual scenario sets the initial conditional premise of the argument, then its true conclusion holds only as a counterfactual truth. The present paper illustrates this criticism using Frank Jackson’s thought experiment, the so-called knowledge argument, as a concrete example. (shrink)

David Atkinson asks whether nonempirical constructions can lead to genuine knowledge in science, and answers in the negative. Thought experiments, in his view, are to be commended only insofar as they eventually lead to real experiments. The claim does not rely on a general study, conceptual or historical, of thought experiments as such: the range of the paper is at once narrower and broader. Atkinson views thought experiments as commonly understood as just one kind of episode in the development of (...) physics in which real experimentation is bypassed, and he believes that such episodes are justified only inasmuch as they are transitory stages on the way to genuine empirical inquiry. Atkinson wants to kill with one arrow what is usually regarded as two different birds: the notion that thought experiments proper can be persuasive in themselves, and the thesis that theories which cannot be brought to the tribunal of experience can nevertheless belong to science. He thus implicitly opposes three views which are commonly, albeit not universally, held: (i) some thought experiments are conclusive; (ii) some theories belong to science despite not being evidently and concretely amenable to empirical corroboration; (iii) the two issues are largely independent. The standpoint from which Atkinson operates is a rather strict form of empiricism, one which relies on a fairly sharp distinction between the conceptual and empirical dimensions of inquiry. My outlook is rather different: the conceptual and empirical seem to me to be intertwined, both conceptually, as suggested by Quine’s critique of logical positivism, and empirically, as revealed by the evidence provided by science itself in its daily and historical reality. Rather than take the high road, I propose to focus first on the critique to which Atkinson subjects Galileo’s thought experiment, and the lessons he draws from his analysis.. (shrink)

I argue that Plato’s use of thought experiments anticipate many of the themes discussed by Thomas S. Kuhn’s classic essay, “A Function for Thought Experiments.” Kuhn’s concern is that thought experiments satisfy the condition of verisimilitude. That is, thought experiments must not be conducted merely to alter the conceptual apparatus of the scientist regarding the phenomenon explored, but rather to alter the scientist’s conceptual apparatus for the sake of altering his actions (i.e., practical rationality). Plato, too, is quite concerned with (...) getting interlocutors to appreciate that theory not be separated from practice, and that theory is necessary for the process of effective decision making. Each of the interlocutors presented in the Republic, Apology and Alcibiades Minor are confrontedwith a thought experiment that is designed to effect how they choose to live. Although the three dialogues I discuss illustrate the Kuhnian admonishment against separating theory form practice, many other dialogues in the Platonic corpus echo Kuhn’s concerns. (shrink)

Against Norton's claim that all thought experiments can be reduced to explicit arguments, I defend Brown's position that certain thought experiments yield a priori knowledge. They do this, I argue, not by allowing us to perceive “Platonic universals” (Brown), even though they may contain non-propositional components that are epistemically indispensable, but by helping to identify certain tacit presuppositions or “natural interpretations” (Feyerabend's term) that lead to a contradiction when the phenomenon is described in terms of them, and by suggesting a (...) new natural interpretation in terms of which the phenomenon can be redescribed free of contradiction. (shrink)

This chapter will discuss the role of thought experiments in science and in science teaching. The constructive and destructive roles played by thought experiments in the construction of scientific theories can be used in science teaching to help students to understand the processes of science. In addition, they have potential to be used as a teaching tool for developing students’ conceptual understanding. The use of thought experiments can also increase students’ interest in science and help them in understanding situations beyond (...) their everyday experiences. It has been reported elsewhere that the use of thought experiments in science teaching may be challenging for both teachers and students. Despite the recent increase in research activities with respect to thought experiments in science education, further systematic research work is still needed for the most effective methods to be discovered of how best to use thought experiments in science teaching. Of particular importance will be studies that focus on science teachers’ understanding of thought experiments and their actual use in a classroom environment. (shrink)

My theme is thought experiment in natural science, and its relation to real experiment. I shall defend the thesis that thought experiments that do not lead to theorizing and to a real experiment are generally of much less value that those that do so. To illustrate this thesis I refer to three examples, from three very different periods, and with three very different kinds of status. The first is the classic thought experiment in which Galileo imagined that he had, by (...) pure thought, demolished Aristoteles' dogma that heavier bodies fall more quickly than light ones. I will show that he was mistaken. The second is the Einstein-Podolsky-Rosen paper purporting to show that quantum mechanics must be incomplete in its domain of application. This thought experiment is a very good one, not because its conclusions are correct, but precisely because it was fruitful, leading to theory and, above all, to a real experiment. Finally I discuss the modern string theory of everything, which, while it is regarded as a physical theory by its instigators, shares some properties of the least successful sort of thought experiment. (shrink)

Both entertaining and startling, The Pig That Wants to Be Eaten offers one hundred philosophical puzzles that stimulate thought on a host of moral, social, and personal dilemmas. Taking examples from sources as diverse as Plato and Steven Spielberg, author Julian Baggini presents abstract philosophical issues in concrete terms, suggesting possible solutions while encouraging readers to draw their own conclusions: Lively, clever, and thought-provoking, The Pig That Wants to Be Eaten is a portable feast for the mind that is sure (...) to satisfy any intellectual appetite. BACKCOVER: “Thinking again is what this taut, incisive, bullet-hard book is dedicated to promoting.” —The Sunday Times (London) “This book is like the Sudoku of moral philosophy: apply your mind to any of its ‘thought experiments’ while stuck on the Tube, and quickly be transported out of rush-hour hell.” —New Statesman. (shrink)

This book includes experiments that cover identity, religion, art, ethics, language, knowledge and more.

The second edition of this popular compendium provides the necessary intellectual equipment to engage with and participate in effective philosophical argument, reading, and reflection Features significantly revised, updated and expanded entries, and an entirely new section drawn from methods in the history of philosophy This edition has a broad, pluralistic approach--appealing to readers in both continental philosophy and the history of philosophy, as well as analytic philosophy Explains difficult concepts in an easily accessible manner, and addresses the use and application (...) of these concepts Proven useful to philosophy students at both beginning and advanced levels. (shrink)

Nevertheless, I believe that, as it has been construed recently, the assumption is false. At the very least, it does not deserve the largely unquestioned status it enjoys, as I hope to show by a graduated series of thought experiments. I present the thought experiments as a series to expose a shared inadequacy in a variety of individualistic views, from type-type physicalism to the most sophisticated methodological solipsism; and I present them as graduated to suggest that having accepted the first (...) relatively uncontroversial story, one has no principled place to demur later. (shrink)

This essay concerns the question of how we make genuine epistemic progress through conceptual analysis. Our way into this issue will be through consideration of the paradox of analysis. The paradox challenges us to explain how a given statement can make a substantive contribution to our knowledge, even while it purports merely to make explicit what one’s grasp of the concept under scrutiny consists in. The paradox is often treated primarily as a semantic puzzle. However, in “Sect. 1” I argue (...) that the paradox raises a more fundamental epistemic problem, and in “Sects.1 and 2” I argue that semantic proposals—even ones designed to capture the Fregean link between meaning and epistemic significance—fail to resolve that problem. Seeing our way towards a real solution to the paradox requires more than semantics; we also need to understand how the process of analysis can yield justification for accepting a candidate conceptual analysis. I present an account of this process, and explain how it resolves the paradox, in “Sect. 3”. I conclude in “Sect. 4” by considering the implications for the present account concerning the goal of conceptual analysis, and by arguing that the apparent scarcity of short and finite illuminating analyses in philosophically interesting cases provides no grounds for pessimism concerning the possibility of philosophical progress through conceptual analysis. (shrink)

…A reconstructed imaginal account of Alexander’s (the Great) historical letter to Aristotle pursuant to his (in-) famous meeting with the gymnosophist Dandimus on the paradoxes of Zeno ( presaging those of Nagarjuna ) as a means of presenting a synthesis of the stasis and dynamism implicit in the potential of a phenomenally real world beyond a rigid designation of a chain-of-being taxonomy where animal dignity resides side by side with predator-prey relations and a mind-laden ( theory ) of evolution.

The thought-experiment presented by Bernard Williams in 'The self and the future' continues to draw the attention of writers in the debate about personal identity. While few of them agree on what implications it has for the debate, almost all agree that those implications are significant ones. Some have even claimed that it has consequences not only for personal identity, but also concerning the viability of thought-experiment as a method. This paper surveys what these consequences might be at both levels (...) - as a substantive contribution to the debate on identity, and as to what it shows about the usefulness of thought-experiments. It argues ultimately that thought-experiments like Williams's do provide a useful philosophical tool as long as we temper our expectations of them, and that it offers some support to a view of personal identity but one which is at odds with Williams's own view. (shrink)

Nils-Frederic Wagner takes issue with my argument that influential critics of “transplant” thought experiments make two cardinal mistakes. He responds that the mistakes I identify are not mistakes at all. The mistakes are rather on my part, in that I have not taken into account the conceptual genesis of personhood, that my view of thought experiments is idiosyncratic and possibly self-defeating, and in that I have ignored important empirical evidence about the relationship between brains and minds. I argue that my (...) case still stands and that transplant thought experiments can do damage to rivals of a psychological continuity theory of personal identity like Marya Schechtman’s Person Life View. (shrink)

Paul Ricoeur and Marya Schechtman express grave doubts about the acceptability and informativeness of the thought-experiments employed by analytic philosophers (notably Derek Parfit) in the debate about personal identity, and for what appear to be related reasons. I consider their reasoning and argue that their reasons fail to justify their doubts. I go on to argue that, from this discussion of possible problems concerning select thought-experiments, something positive can be learned about personal identity.

While theories about interpreting biblical and other parables have long realised the importance of readers’ responses to the topic, recent results in social psychology concerning systematic self-deception raise unforeseen problems. In this paper I first set out some of the problems these results pose for the authority of fictional thought-experiments in moral philosophy. I then consider the suggestion that biblical parables face the same problems and as a result cannot work as devices for moral or religious instruction in the way (...) that they are usually understood to work. I examine a number of influential theories about interpretation of the parables which might appear to deflect the problems, and argue that none of them are ultimately successful in doing so. (shrink)

Philosophers have traditionally used thought-experiments in their endeavours to find a satisfactory account of the self and personal identity. Yet there are considerations from empirical psychology as well as related ones from philosophy itself that appear to completely undermine the method of thought-experiment. This paper focuses on both sets of considerations and attempts a defence of the method.

The paper takes a close look at Derek Parfit’s example of the Nineteenth Century Russian in 'Reasons and Persons'. Parfit presents it as an example which illustrates the moral consequences of adopting his reductionist view of personal identity in a positive light. I argue that things turn out to be more complex than he envisages, and that it might be far more difficult to live in his world than he allows.

The aim of this paper is to re-evaluate the manner in which the Ticking Bomb Scenario (TBS), a thought experiment in philosophical enquiry, has been used in the discussion of the justifiability or otherwise of forward-looking interrogational torture (FLIT). The paper argues that criticisms commonly raised against the thought experiment are often inappropriate or irrelevant. A great many criticisms misunderstand the way in which thought experiments in general, and the TBS in particular, are supposed to work in philosophical (and for (...) that matter scientific) inquiry. The paper is not about the acceptability or otherwise of FLIT per se but rather an attempt to show that thought experiments such as the TBS are useful analytic tools and ought not to be rejected due to their inappropriate use by those engaged in the justifiability or otherwise of FLIT. By rescuing the TBS from its erroneous use the paper seeks to show its proper worth as part of an argumentative device in uncovering conflicting moral intuitions in our search for ethical truths. (shrink)

I want to model a finite, fallible cognitive agent who imagines that p in the sense of mentally representing a scenario—a configuration of objects and properties—correctly described by p. I propose to capture imagination, so understood, via variably strict world quantifiers, in a modal framework including both possible and so-called impossible worlds. The latter secure lack of classical logical closure for the relevant mental states, while the variability of strictness captures how the agent imports information from actuality in the imagined (...) non-actual scenarios. Imagination turns out to be highly hyperintensional, but not logically anarchic. Section 1 sets the stage and impossible worlds are quickly introduced in Sect. 2. Section 3 proposes to model imagination via variably strict world quantifiers. Section 4 introduces the formal semantics. Section 5 argues that imagination has a minimal mereological structure validating some logical inferences. Section 6 deals with how imagination under-determines the represented contents. Section 7 proposes additional constraints on the semantics, validating further inferences. Section 8 describes some welcome invalidities. Section 9 examines the effects of importing false beliefs into the imagined scenarios. Finally, Sect. 10 hints at possible developments of the theory in the direction of two-dimensional semantics. (shrink)

I present an approach to our conceiving absolute impossibilities—things which obtain at no possible world—in terms of ceteris paribus intentional operators: variably restricted quantifiers on possible and impossible worlds based on world similarity. The explicit content of a representation plays a role similar in some respects to the one of a ceteris paribus conditional antecedent. I discuss how such operators invalidate logical closure for conceivability, and how similarity works when impossible worlds are around. Unlike what happens with ceteris paribus counterfactual (...) conditionals, the closest worlds are relevantly closest belief-worlds: closest to how things are believed to be, rather than to how they are. Also, closeness takes into account apriority and the opacity of intentional contexts. (shrink)

The Humean view that conceivability entails possibility can be criticized via input from cognitive psychology. A mainstream view here has it that there are two candidate codings for mental representations (one of them being, according to some, reducible to the other): the linguistic and the pictorial, the difference between the two consisting in the degree of arbitrariness of the representation relation. If the conceivability of P at issue for Humeans involves the having of a linguistic mental representation, then it is (...) easy to show that we can conceive the impossible, for impossibilities can be represented by meaningful bits of language. If the conceivability of P amounts to the pictorial imaginability of a situation verifying P, then the question is whether the imagination at issue works purely qualitatively, that is, only by phenomenological resemblance with the imagined scenario. If so, the range of situations imaginable in this way is too limited to have a significant role in modal epistemology. If not, imagination will involve some arbitrary labeling component, which turns out to be sufficient for imagining the impossible. And if the relevant imagination is neither linguistic nor pictorial, Humeans will appear to resort to some representational magic, until they come up with a theory of a ‘third code’ for mental representations. (shrink)

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. (shrink)

: An examination of two thought experiments in contemporary physics reveals that the same thought experiment can be reanalyzed from the perspective of different and incompatible theories. This fact undermines those accounts of thought experiments that claim their justificatory power comes from their ability to reveal the laws of nature. While thought experiments do play a genuine evaluative role in science, they do so by testing the nonempirical virtues of a theory, such as consistency and explanatory power. I conclude that, (...) while their interpretation presupposes a whole set of background theories and putative laws, thought experiments nonetheless can evolve and be retooled for different theories and ends. (shrink)

In this paper a unified theory of models and thought experiments is proposed by considering them as fictions, la Vaihinger. In order to reach this aim, the Hertzian and Botzmannian interpretation of theories as Bilder is reconsidered.

The literature on thought experiments has been mainly concerned with thought experiments that are directed at a theory, be it in a constructive or a destructive manner. This has led some philosophers to argue that all thought experiments can be formulated as arguments. The aim of this paper is to draw attention to a type of thought experiment that is not directed at a theory, but fulfills a specific function within a theory. Such thought experiments are referred to as functional (...) thought experiments, and they are routinely used in applied statistics. An example is given from frequentist statistics, where a thought experiment is required to establish the probability space. It is concluded that (a) not all thought experiments can be formulated as arguments, and (b) the role of thought experiments is more general and more important to scientific reasoning than has previously been recognized. (shrink)

Ce texte propose de prendre au sérieux l’expérience de pensée d’une rencontre extraterrestre, pour poser à la philosophie politique et morale le défi d’une rencontre de l’altérité radicale. En se demandant comment accueillir des non-humains non-terriens, cet article argumente en faveur d’une politique de l’hospitalité, comme alternative aux propositions posthumanistes souvent trop abstraites. L’hospitalité offre une série d’épreuves qui permettent de déterminer la nature d’entités inconnues et d’affuter notre sensibilité à leur égard. Le détour par la science-fiction permet ainsi de (...) penser la responsabilité. -/- This text proposes that we take the thought experiment of an extraterrestrial encounter seriously and set political and moral philosophy the challenge of addressing an encounter with radical alterity. By asking how we might welcome extraterrestrial non-humans, this article argues in favor of a policy of hospitality, as an alternative to posthumanist proposals that are often too abstract. Hospitality offers a series of tests to help us determine the nature of unknown entities and to attune our sensibility towards them. Taking a trip through science fiction allows us to reflect on our responsibility in the face of a radical alterity. (shrink)

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. (shrink)

Theories often run into paradoxes. Some of these are outright contradictions, sending the would-be champions of the theory back to the drawing board. Others are paradoxical in the sense of being bizarre and unexpected. The latter are sometimes mistakenly thought to be instances of the former. That is, they are thought to be more than merely weird; they are mistakenly thought to be self-refuting. Showing that they are not self-contradictory but merely a surprise is often a challenge. Notions of explanation (...) and understanding are often at issue. For instance, we might explain—or explain away—a paradox by invoking some mechanism provided by the theory and showing how it does not really lead to a logically incoherent .. (shrink)