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)

Unlike in physics, the category of thought experiment is not very common in biology. At least there are no classic examples that are as important and as well-known as the most famous thought experiments in physics, such as Galileo’s, Maxwell’s or Einstein’s. The reasons for this are far from obvious; maybe it has to do with the fact that modern biology for the most part sees itself as a thoroughly empirical discipline that engages either in (...) real natural history or in experimenting on real organisms rather than fictive ones. While theoretical biology does exist and is recognized as part of biology, its role within biology appears to be more marginal than the role of theoretical physics within physics. It could be that this marginality of theory also affects thought experiments as sources of theoretical knowledge. Of course, none of this provides a sufficient reason for thinking that thought experiments are really unimportant in biology. It is quite possible that the common perception of this matter is wrong and that there are important theoretical considerations in biology, past or present, that deserve the title of thought experiment just as much as the standard examples from physics. Some such considerations may even be widely known and considered to be important, but were not recognized as thought experiments. In fact, as we shall see, there are reasons for thinking that what is arguably the single most important biological work ever, Charles Darwin’s On the Origin of Species, contains a number of thought experiments. There are also more recent examples both in evolutionary and non-evolutionary biology, as we will show. Part of the problem in identifying positive examples in the history of biology is the lack of agreement as to what exactly a thought experiment is. Even worse, there may not be more than a family resemblance that unifies this epistemic category. We take it that classical thought experiments show the following characteristics: They serve directly or indirectly in the non-empirical epistemic evaluation of theoretical propositions, explanations or hypotheses. Thought experiments somehow appeal to the imagination. They involve hypothetical scenarios, which may or may not be fictive. In other words, thought experiments suppose that certain states of affairs hold and then try to intuit what would happen in a world where these suppositions are true. We want to examine in the following sections if there are episodes in the history of biology that satisfy these criteria. As we will show, there are a few episodes that might satisfy all three of these criteria, and many more if the imagination criterion is dropped or understood in a lose sense. In any case, this criterion is somewhat vague in the first place, unless a specific account of the imagination is presupposed. There will also be issues as to what exactly “non-empirical” means. In general, for the sake of discussion we propose to understand the term “thought experiment” here in a broad rather than a narrow sense here. We would rather be guilty of having too wide a conception of thought experiment than of missing a whole range of really interesting examples. (shrink)

Most disciplines make use of thought experiments, but physics and philosophy lead the pack with heavy dependence upon them. Often this is for conceptual clarification, but occasionally they provide real theoretical advances. In spite of their importance, however, thought experirnents have received rather little attention as a topic in their own right until recently. The situation has improved in the past few years, but a mere generation ago the entire published literature on thought experiments (...) could have been mastered in a long weekend. Now the subject is beginning to flourish. Given the relative newness of the field, it might be useful to have several examples at one’s finger tips, so a number of great ones will be described. Attention will also be drawn outside physics and philosophy. In mathematics there is something analogous to thought experiments -- visual reasoning and picture proofs. I will look briefly at this class of thought experiments and try using them to make a case for possibly settling the continuum hypothesis. After this, I will return to thought experiments in the sciences and propose an account of how they work. Finally, I will end with a sketch of a topic I am currently working on, a kind of progress report which, I hope, will be an inducement to others. (shrink)

Newton's bucket, Einstein's elevator, Schrödinger's cat – these are some of the best-known examples of thought experiments in the natural sciences. But what function do these experiments perform? Are they really experiments at all? Can they help us gain a greater understanding of the natural world? How is it possible that we can learn new things just by thinking? In this revised and updated new edition of his classic text _The Laboratory of the Mind_, James Robert (...) Brown continues to defend apriorism in the physical world. This edition features two new chapters, one on “counter thought experiments” and another on the development of inertial motion. With plenty of illustrations and updated coverage of the debate between Platonic rationalism and classic empiricism, this is a lively and engaging contribution to the field of philosophy of science. (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)

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)

This is a review of those key thought experiments in physics from the late 19th century onward that seem to have played a particular role in the process of the discovery or advancement of theory. Among others the paper discusses Maxwell's demon, several of Einstein's thought experiments in relativity, Heisenberg's microscope, the Einstein-Schrödinger cat, and the EPR thought experiment.

This article concerns the way in which philosophers study the epistemology of scientific thought experiments. Starting with a general overview of the main contemporary philosophical accounts, we will first argue that two implicit assumptions are present therein: first, that the epistemology of scientific thought experiments is solely concerned with factual knowledge of the world; and second, that philosophers should account for this in terms of the way in which individuals in general contemplate these thought (...) class='Hi'>experiments in thought. Our goal is to evaluate these assumptions and their implications using a particular case study: Albert Einstein's magnet-conductor thought experiment. We will argue that an analysis of this thought experiment based on these assumptions – as John Norton (1991) provides – is, in a sense, both misguided (the thought experiment by itself did not lead Einstein to factual knowledge of the world) and too narrow (to understand the thought experiment's epistemology, its historical context should also be taken into account explicitly). Based on this evaluation we propose an alternative philosophical approach to the epistemology of scientific thought experiments which is more encompassing while preserving what is of value in the dominant view. (shrink)

Husserl holds the view that givenness through adumbrations (i.e. perspectival givenness) is an essential characteristic of the givenness of spatiotemporal things. He goes so far to say that we are dealing with an essential law. In this article I try to make sense of this claim. I am also dealing with a thought experiment that is designed to show that the givenness through adumbrations is just a consequence of our physiological make-up, a view that Husserl explicitly rejects. Amongst other (...) things, I defend Husserl by introducing the crucial distinction between first-person-imagination and third-person-imagination. (shrink)

Proponents of the “negative program” in experimental philosophy have argued that judgements in philosophical cases, also known as case judgements, are unreliable and that the method of cases should be either strongly constrained or even abandoned. Here we put one of the main proponent’s account of why philosophical cases may cause the unreliability of case judgements to the test. We conducted our test with thought experiments from physics, which exhibit the exact same supposedly “disturbing characteristics” of philosophical (...) cases. (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)

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)

The history of mechanics has been extensively investigated in a number of historical works. The full story from the Greeks and medievals through the Scientific Revolution to the modern era is long and complex. But it is also incomplete. Studies to date have been admirably thorough in putting empirical discoveries into proper perspective and in making clear the great importance of mathematical innovations. But there has been surprisingly little regard for the role of thought experiments in the development (...) of mechanics. We attempt to rectify this, at least in part. After a brief account of Greek ideas of space and motion, we focus on late medieval and early modern physics, especially the development of inertial motion. In particular, we examine the thought experiments of Buridan, Oresme, and Galileo, which did so much to undermine Aristotle’s account of motion and lead the way to the modern concept of inertia. (shrink)

Abstract Thought experimentation is part of accepted scientific practice, and this makes it surprising that philosophers of science did not seriously engage with it for a very long time. The situation changed in the 1990s, resulting in a highly intriguing debate over thought experiments. Initially, the discussion focused mostly on thought experiments in physics, philosophy, and mathematics. Other disciplines have since become the subject of interest. Yet, nothing substantial has been said about the role (...) of thought experiments in nonphilosophical theology. This paper discusses the role of thought experiments in Christian theology in comparison to their role in quantum physics, as mentioned by John Polkinghorne in Quantum Physics and Theology. We first look briefly at the history of the inquiry into thought experiments and then at Polkinghorne's remarks about the role of thought experimentation in quantum physics and Christian eschatology. To determine the actual importance of thought experiments in Christian theology a number of new examples are introduced in a third step. In the light of these examples, in a fourth step, we address the question of what it is that explains the cognitive efficacy of thought experiments in quantum physics and Christian theology. (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)

Thought experiments have a mysterious way of informing us about the world, apparently without examining it, yet with a great degree of certainty. It is tempting to try to explain this capacity by making use of the idea that in thought experiments, the mind somehow simulates the processes about which it reaches conclusions. Here, I test this idea. I argue that when they predict the outcomes of hypothetical physical situations, thought experiments cannot simulate physical (...) processes. They use mental models, which should not be confused with process-driven simulations. A convincing case can be made that thought experiments about hypothetical mental processes are mental simulations. Concerning moral thought experiments, I argue that construing them as simulations of mental processes favours certain moral theories over others. The scope of mental simulation in thought experiments is primarily limited by the constraint of relevant similarity on source and target processes: on one hand, this constraint disqualifies thought from simulating external natural processes; on the other hand, it is a source of epistemic bias in moral thought experiments. In view of these results, I conclude that thought experiments and mental simulations cannot be assimilated as means of acquiring knowledge. (shrink)

Scientists often make use of epistemic representations in order to perform investigations about the real world. So far, philosophers of science interested in epistemic representation of this sort have mostly focused on scientific models. In this thesis, I argue that there are other interesting instances of representation besides models: thought experiments, experimental organisms, and mechanically-produced pictures. These represent portions of the world in the same way as models do, if the concept of epistemic representation is properly understood. In (...) Chapter 1, I introduce and develop the idea that a system functions as an epistemic representation of a designated target system insofar as it is interpreted as a symbol that both possesses and highlights some properties that are then to be imputed to that target system via a proper de-idealising function. In the main body of the thesis, I analyse the above-mentioned types of representations and argue that they function as representations in the same way as scientific models. Chapter 2 discusses the use of thought experiments in physics, with particular focus on Galileo’s thought experiment that illustrates the principle of inertia. Chapter 3 focuses on experimental organism research in biology, with specific attention to the Drosophila melanogaster. Finally, Chapter 4 is about the epistemic use of mechanically produced pictures with the picture of a black hole as the primary case study. In each chapter, I further show that by studying these types of representation through the lens of the account developed in Chapter 1, one can (dis)solve specific issues about thought experiments, model organisms, and pictures respectively. In Chapter 5, I further defend my proposal from scepticism about the concept of representation and its application to these different cases. Chapter 6 concludes the thesis by illustrating the most general implications of my analysis and proposing routes for future enquiry. (shrink)

The aim of this paper is to show how thought experiments help us learn about laws. After providing examples of this kind of nomic illumination in the first section, I canvass explanations of our modal knowledge and opt for an evolutionary account. The basic application is that the laws of nature have led us to develop rough and ready intuitions of physical possibility which are then exploited by thought experimenters to reveal some of the very laws responsible (...) for those intuitions. The good news is that natural selection ensures a degree of reliability for the intuitions. The bad news is that the evolutionary account seems to limit the range of reliable thought experiment to highly practical and concrete contexts. In the fifth section, I provide reasons for thinking that we are not as slavishly limited as a pessimistic construal of natural selection suggests. Nevertheless, I promote the idea that biology is a promising source of predictions and diagnoses of thought experiment failures. (shrink)

The role of intuition in understanding in general and in scientific understanding in particular is still very much a subject of a lively philosophical discussion. The role of intuition in thought experimenting is much disputed in its own right, and the arguments range from those that deny any substantial role of intuition in the final inference that the thought experiment is meant to illustrate (eg. Norton or Williamson) to the pivotal role some form of intuition might play (eg. (...) Brown or Miščević). So far, mostly Platonists were defenders of intuition, but in his recent book, Miščević takes on a formidable task to mount a defense of intuition as seen from a naturalist-evolutionist point of view and within his mental modelling approach to thought experiments. I will, while acclaiming certain – and considerable – merits of his approach, nevertheless, insist that certain aspects of intuitive comprehending as it is meant to be going on in the process of thought experimenting remains inexplicable in the naturalist scheme such as Miščević’s. The more mysterious (not to say Platonist) aspects of intuition will, hopefully, be revealed through the analyses of the two very famous thought experiments of Einstein which also figure quite importantly in his scientific opus. I will also have something to say about a few related problems as addressed by Miščević in his book regarding the description of thought experiment and more general imaginative enactments in thought, as well as on whether there is an essential difference between scientific (primarily physical) and metaphysical thought experiments and other thought experiments or related modes of thinking. (shrink)

Scientists investigating the thermal properties of black holes rely heavily on theoretical and non-empirical tools, such as mathematical derivations, analogue experiments and thought experiments. Although the use of mathematical derivations and analogue experiments in the context of black hole physics has recently received a great deal of attention among philosophers of science, the use of thought experiments (TEs) in that context has been almost completely neglected. In this paper, we will start filling this (...) gap by systematically analyzing the epistemic role of the two TEs that gave birth to black hole thermodynamics, namely Wheeler’s demon and Geroch’s engine. We will argue that the two main epistemic functions of these TEs are to reveal and resolve inconsistencies, in line with El Skaf’s (Probing theoretical statements with thought experiments. Synthese 199:6119–6147, 2021) approach to TEs. We will, then, go beyond El Skaf’s approach by stressing an important difference between the strategies employed to assess the reliability of each epistemic function. (shrink)

The scales across which physical properties exist are vast and subtle in their effects on particular systems placed locally on such scales. For example, human experiential access is restricted only to partial segments of the mass density, size, and temperature scales of the universe. I argue that philosophers must learn to appreciate better the effects of physical scales. Specifically, thought experiments in philosophy should be more sensitive to physical scale effects, because the conclusion of a thought experiment (...) may be undermined by unintentionally ignored scale effects, and the changes required to obtain the foreground state of affairs in a thought experiment might require unacknowledged scale-spanning changes to the contextual background. I discuss four philosophical thought experiments: Putnam's Twin Earth and Brain in a Vat, Searle's Chinese Room, and Chalmers's Zombies Without Qualia. I close by briefly defending the greater interest and importance of physical possibility over logical possibility. (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)

Experiments (E), computer simulations (CS) and thought experiments (TE) are usually seen as playing different roles in science and as having different epistemologies. Accordingly, they are usually analyzed separately. We argue in this paper that these activities can contribute to answering the same questions by playing the same epistemic role when they are used to unfold the content of a well-described scenario. We emphasize that in such cases, these three activities can be described by means of the (...) same conceptual framework—even if each of them, because they involve different types of processes, fall under these concepts in different ways. We further illustrate our claims by presenting a threefold case study describing how a TE, a CS and an E were indeed used in the same role at different periods to answer the same questions about the possibility of a physical Maxwellian demon. We also point at fluid dynamics as another field where these activities seem to be playing the same unfolding role. We analyze the importance of unfolding as a general task of science and highlight how our description in terms of epistemic functions articulates in a noncommittal way with the epistemology of these three activities and accounts for their similarities and the existence of hybrid forms of activities. We finally emphasize that picturing these activities as functionally substitutable does not imply that they are epistemologically substitutable. (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)

Good physical experiments conform to the basic methodological standards of experimental design: they are objective, reliable, and valid. But is this also true of thought experiments? Especially problems of personal identity have engendered hypothetical scenarios that are very distant from the actual world. These imagined situations have been conspicuously ineffective at resolving conflicting intuitions and deciding between the different accounts of personal identity. Using prominent examples from the literature, I argue that this is due to many of (...) these thought experiments not adhering to the methodological standards that guide experimental design in nearly all other disciplines. I also show how empirically unwarranted background assumptions about human physiology render some of the hypothetical scenarios that are employed in the debate about personal identity highly misleading. (shrink)

I provide some considerations on scientific thought experiments, focusing on their epistemic value. First, I outline the distinctive features of scientific thought experiments, provide some historical background and, as an illustration, describe two thought experiments: Galileo's on falling bodies and Stevin's on inclined plane. I take thought experiments in physics as an example from which more general conclusions can be drawn - about thought experiments in other natural sciences, but (...) also in philosophy, mathematics, and other sciences. Further, I present Kuhn's epistemic puzzle as well as some proposed solutions. This closely relates to the question what kind of processes are involved in scientific thought experimenting. The satisfactory answer must consider scientific discoveries. I outline the mental model account as the most promising account since it best incorporates the findings of cognitive science. I conclude with two issues that the account needs to resolve and the role cognitive science can play in this. (shrink)

I consider various experiments related to the so-called “macroscopic quantum coherence” experiment, which are probably at present in the class of “thought” experiment but are likely to become realistic in the next few decades. I explore the way in which outcomes consistent with the predictions of quantum mechanics would be interpreted by an adherent of, respectively, the Copenhagen, statistical, and Bohmian interpretations of the formalism.

Thought experiments are a means of imaginative reasoning that lie at the heart of philosophy, from the pre-Socratics to the modern era, and they also play central roles in a range of fields, from physics to politics. The Routledge Companion to Thought Experiments is an invaluable guide and reference source to this multifaceted subject. Comprising over 30 chapters by a team of international contributors, the Companion covers the following important areas: -/- · the history of (...) thought experiments, from antiquity to the trolley problem and quantum non-locality; -/- · thought experiments in the humanities, arts, and sciences, including ethics, physics, theology, biology, mathematics, economics, and politics; -/- · theories about the nature of thought experiments; -/- · new discussions concerning the impact of experimental philosophy, cross-cultural comparison studies, metaphilosophy, computer simulations, idealization, dialectics, cognitive science, the artistic nature of thought experiments, and metaphysical issues. -/- This broad ranging Companion goes backwards through history and sideways across disciplines. It also engages with philosophical perspectives from empiricism, rationalism, naturalism, skepticism, pluralism, contextualism, and neo-Kantianism to phenomenology. This volume will be valuable for anyone studying the methods of philosophy or any discipline that employs thought experiments, as well as anyone interested in the power and limits of the mind. (shrink)

In this chapter, the author presents some Cartesian thought experiments by reproducing an excerpt from The Meditations on First Philosophy. The author asks us to imagine that the physical world around us is an elaborate illusion. He imagines that the world was merely a dream or, worse yet, a hoax orchestrated by an evil demon bent on deceiving us. The author asks us to suppose that we are dreaming, and that some particulars ‐ namely, the opening of the (...) eyes, the motion of the head, the forth‐putting of the hands ‐ are merely illusions; and even that we really possess neither an entire body nor hands such as we see. Nevertheless, he says that, it must be admitted at least that the objects which appear to us in sleep are, as it were, painted representations which could not have been formed unless in the likeness of realities. (shrink)

The ‘Fading Qualia’ thought experiment of Chalmers purports to show that computationalism is very probably true even if dualism is true by considering a series of brains, with biological parts increasingly substituted for by artificial but functionally analagous parts in small steps, and arguing that consciousness would not plausibly vanish in either a gradual or sudden way. This defense of computationalism inspired an attack on computationalism by Bishop, who argued that a similar series of substitutions by parts that have (...) the correct physical activity but not the correct causal relationships must likewise preserve consciousness, purportedly showing that ‘Counterfactuals Cannot Count’ and if so ruining a necessary condition for computation to meaningfully distinguish between physical systems. In this paper, the case in which a series of parts are simply removed and substituted for only by imposing the correct boundary conditions to exactly preserve the functioning of the remaining partial brain is described. It is argued that consciousness must gradually vanish in this case, not by fading but by becoming more and more partial. This supports the non-centralized nature of consciousness, tends to support the plausibility of physicalism against dualism, and provides the proper counterargument to Bishop’s contention. It also provides an avenue of attack against the “Fading Qualia” argument for those who remain dualists. (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)

In §69.b of BT Heidegger attempts an existential genetic analysis of science, i.e. a phenomenology of the conceptual process of the constitution of the logical view of science (science seen as theory) starting from the Dasein. It attempts to do so by examining the special intentional-existential modification of (human) being-in-the-world, which is called the "mathematical projection of nature"; that is, by examining that special modification of our being, which places us in the state of experience that presents the world to (...) us as taught by, e.g., Galileo and Newton. The idea he puts forward is that modern mathematical physics and the corresponding experience of the real is the result of the mathematical projection of nature. Modern science, Heidegger says, stands out because it is mathematical. But we cannot get the answer to what this mathematicality consists in from mathematics, because mathematics is only a special manifestation of mathematicality. Here is what Heidegger means by "mathematicality" and, accordingly by "mathematical projection of nature." If one were to let two bodies of different weights fall simultaneously from the top of the tower of Pisa, Heidegger notes, both Galileo and an Aristotelian would see that the two bodies would reach the ground with as little time difference as possible, and not at exactly the same moment. Galileo, however, does something decisive: he claims that under conditions that would be impossible to ensure (if we removed absolutely all resistance to the motion of the bodies), the two bodies would reach the ground absolutely simultaneously. This is not something that he or the Aristotelian sees happening empirically. How, then, does Galileo insist so firmly on his position? How exactly does it happen that he has before him such a view of things? Heidegger's answer is that Galileo is mathematically projecting nature. In his Dialogues Galileo says "I conceive with my mind" (mente concipio) a body thrown to move on an infinitely extending horizontal plane, having eliminated from its path every possible obstacle. Finally, I argue that from the detailed interpretation of Heidegger's points of the mathematical and of the notion of mathematical projection of nature, we can arrive at the conclusions I had arrived at in my doctoral dissertation (2000) as regards the meaning and function of thought experiments in physics as seen from a Husserlian phenomenological point of view as intentional acts. In a nutshell, in thought experiments physics constitutes the special metaphysics (to use the Kantian term) of the primordial ontological region it investigates as well as attempts to make natural sense of the mathematical formalism in cases it proves necessary. (shrink)

Thought experiments have played a prominent role in numerous cases of conceptual change in science. I propose that research in cognitive psychology into the role of mental modeling in narrative comprehension can illuminate how and why thought experiments work. In thought experimenting a scientist constructs and manipulates a mental simulation of the experimental situation. During this process, she makes use of inferencing mechanisms, existing representations, and general world knowledge to make realistic transformations from one possible (...) physical state to the next. The simulation reveals the impossibility of integrating multiple constraints drawn from existing representations and the world and pinpoints the locus of the required conceptual reform. (shrink)

The goal of this paper is to answer the following question: Does it make sense to speak of thought experiments not only in physics, but also in mathematics, to refer to an authentic type of activity? One may hesitate because mathematics as such is the exercise of reasoning par excellence, an activity where experience does not seem to play an important role. After reviewing some results of the research on thought experiments in the natural sciences, (...) we turn our attention to experiments and thought experiments in mathematics, especially in fundamental mathematics, and investigate what thought experiments can teach us there. If we accept the principle that mathematical practice can sometimes be best described by a pragmatist approach where the concept of experience in mathematics is considered from a new perspective, thought experiments can in some cases be a useful instrument different from both ‘mathematical experiments’ and ‘formal’ proofs: they are mathematical experiments using deviant methods. (shrink)

The way in which philosophers have thought about the scientific method and the nature of good scientific reasoning over the last few centuries has been consistently and heavily influenced by the examples set by physics. The astounding achievements of 19th and 20th century physics demonstrated that physicists had successfully identified methodologies and reasoning patterns that were uniquely well suited to discovering fundamental truths about the natural world. Inspired by this success, generations of philosophers set themselves the goal (...) of taxonomising, codifying, formalising and evaluating these reasoning patterns. Many will concede that this has been a tremendously fruitful exercise that has served both to illuminate characteristic methodological and epistemological features of the physical sciences, and to inform the way that philosophers think about the epistemic ideals served by science more generally. However, as has been widely noted, the great challenges confronted by contemporary physics have led to a number of fundamental shifts in the way that physicists formulate, assess and apply their theories of the physical world. The most prominent examples of this trend occur in the realm of theoretical high energy physics, where many of the most influential theories advocated by physicists lie beyond the reach of extant experimental methods, and are therefore extremely difficult to test empirically. The fact that whole communities of physicists have devoted so much time and effort to evaluating theories that are largely disconnected from experiments and empirical testing suggests that existing philosophical accounts of the epistemology of physics, based as they are on a broadly empiricist conception of physics, are no longer completely apt, or are at least somewhat out of date. This in turn suggests that it is time for philosophers to redirect their attention towards the characteristic reasoning strategies at play in contemporary physics. As well as clarifying the epistemic structure of 21st century physics and providing new stimulation for general debates surrounding the epistemology of science, this will also allow more philosophers to confront and engage with the existential methodological debates currently raging within physics. There is currently intense and wide spread disagreement surrounding what kinds of reasoning strategies can legitimately be employed in the assessment of competing physical theories and research programs. This special issue aims to facilitate the further engagement of philosophers in this crucial debate by collecting eight contributions that both highlight the deep philosophical issues at stake in debates surrounding the proper methodology for theory assessment in physics, and present novel philosophical perspectives on specific reasoning strategies in the physical sciences. (shrink)

The authors undertake a thought experiment the purpose of which is to explore possibilities for understanding moral principles in analogy with cosmic order. The experiment is based on three proposals, which are described in detail: an ontological, a neurological, and a moral proposal. The ontological proposal accepts from the phenomena of quantum physics that there is a nonempirical domain of physical reality that consists not of material things but of what is philosophically conceptualized as a realm of nonmaterial (...) forms. This realm of forms is the realm of potentiality in physical reality that quantum physics posits as an indivisible Wholeness—the One. It is the ultimate reality because everything empirical is the actualization of its forms. The neurological proposal is the hypothesis that the brain is sensitive to the potentiality waves in the cosmic field, as ordinary measuring instruments in physics are sensitive to potentiality waves at the quantum level, so that the cosmic field can communicate with the human brain. The third proposal assumes that the communication with the cosmic field can translate into moral ideas and actions. Even though the three proposals underlying the thought experiment are highly speculative, they lead to definite implications that make sense in their own right and can be applied in a useful way. From the order of reality some simple rules of conduct follow that are identical with traditional moral rules but have the character of rules of well-ness, leading to new aspects of Aristotle's concept of eudaimonia and Kant's concept of the highest good. In analogy with the structure of physical reality, where all empirical phenomena are actualizations of nonempirical forms, it is suggested that the structure of morality, too, is that of a tacit, nonempirical form that actualizes in explicit principles and moral acts through our consciousness. The tacit form is thought to exist in the realm of cosmic potentiality, together with all the other forms that the empirical world actualizes. It can appear spontaneously in our consciousness when needed, offering its guidance to our judgment and free will. Because it does not appear in the form of commandments accompanied by threats, the actions of the tacit moral form define a higher level of morality, similar to that offered by some aspects of the Christian teaching, where one acts not out of fear but on the desire to do things right. (shrink)

In their paper, ‘When are thought experiments poor ones?’ (Peijnenburg and David Atkinson, 2003, Journal of General Philosophy of Science 34, 305-322.), Jeanne Peijnenburg and David Atkinson argue that most, if not all, philosophical thought experiments are “poor” ones with “disastrous consequences” and that they share the property of being poor with some (but not all) scientific thought experiments. Noting that unlike philosophy, the sciences have the resources to avoid the disastrous consequences, Peijnenburg and (...) Atkinson come to the conclusion that the use of thought experiments in science is in general more successful than in philosophy and that instead of concocting more “recherché” thought experiments, philosophy should try to be more empirical. In this comment I will argue that Peijnenburg’s and Atkinson’s view on thought experiments is based on a misleading characterization of both, the dialectical situation in philosophy as well as the history of physics. By giving an adequate account of what the discussion in contemporary philosophy is about, we will arrive at a considerably different evaluation of philosophical thought experiments. For I am convinced that we now find ourselves at an altogether decisive turning point in philosophy, and that we are objectively justified in considering that an end has come to the fruitless conflict of systems. We are already at the present time, in my opinion, in possession of methods which make any such conflict in principle unnecessary. What is now required is their resolute application. (Schlick, ‘The Turning Point in Philosophy’, 1930/1959, p. 54). (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)

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

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

In lieu of an abstract, here is a brief excerpt of the content:The Concept of Experience in Locke and Hume JOHN W. YOLTON THE EMPIRICISTPROGRAM has been designed to show that all conscious experience "comes from" unconscious encounters with the environment, and that all intellectual contents (concepts, ideas) derive from some conscious experiential component. Some empiricists, but not all, have also argued that experience reports about the world. A strict empiricism would have to reject this latter claim, as Hume did, (...) although even to consider the possibility of knowledge being related to an external world is to operate on a reflective level, to seek to make sense of experience. The distinction between an account of the nature of experience--its structure, relations, and contents-and explanations of experience--its causal antecedents, its reference--is an important one. The phrase "the concept of experience" refers to the use made of some account of experience. The concept of experience need not be restricted to the experiential contents. Thus, Locke sought to show how experience is of the world, Hume tried to show how experience restricts our valid conceptual contents to certain sorts of ideas, eliminating others. Any account of experience will already be a conceptualization of experience: it must be made from the reflective level. But the account need be no more than a careful record of how the organism comes to the conscious level. Of course, such an account cannot be a straightforward description, since we cannot directly observe all of the processes operating in the production of awareness. The psychology of awareness is forced to extrapolate and conjecture. Nevertheless, we can still distinguish the psychological or descriptive account of experience from the metaphysical use made of that account. It is my purpose here to explore the accounts given and the uses made of experience by two representative empiricists, that is, by philosophers whom we look upon as advancing the empiricist metaphysic of experience. Locke's Derivation o[ Ideas From Experience Locke claimed that all mental contents come from two sources, sensory experience of the world and introspective awareness of our mental processes. The program of Book II of his Essay was to exemplify, by reference to a [53] 54 HISTORY OF PHILOSOPHY number of different ideas and concepts, this derivation of our mental contents. The counter claim for Locke was innatism, the view held by many of his contemporaries and refuted in the first book of his Essay. In order to appreciate what Locke's alternative to innatism was, we must try to discover what the program of derivation of ideas amounts to in his epistemology and what precisely he understood by the term "experience." We must first note that he offers the program of derivation in conjunction with a complex theory of mental operations. H. H. Price has remarked that it is "historically false that the empiricist thought the human mind passive. It would be more just to criticize them for making it more active than it can possibly be.''1 Mental processes play a most active and decisive role in the genesis of all ideas in Locke's account. In the case of simple ideas of sense even, the mind must be attentive to what the senses report, else that report will go unrecorded, or be recorded only at the neural level (II, I, #6, #8, and II, IX, #3). Locke frequently draws the distinction between mental contents or processes and physical processes. In the "Epistle to the Reader," where he defines "idea," he is careful to distinguish idea from the sound we "use as a sign of it." In I, I, #2 he draws a distinction between the "physical consideration of the mind" and the non-physical consideration, although he does not have a name for the latter. He also speaks there of "sensations by our organs" and "ideas in our understanding." Locke disclaimed any intention of going into the physical account of sensation. He simply accepted the current corpuscular theory. But although he is not always as precise as we would be about the physical and physiological levels of encounter, in distinction from the mental levels, he does hold to this division. II, I, #3, for instance, speaks of the senses conveying "into the mind" several "distinct perceptions... (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)

The aim of this paper is to show that scientific thought experiments and works of science fiction are highly suitable tools for facilitating and increasing understanding of science. After comparing one of Einstein’s most famous thought experiments with the science fiction novel “The Forever War”, I shall argue that both proceed similarly in making some of the more outlandish consequences of special relativity theory intelligible. However, as I will also point out, understanding in thought (...) class='Hi'>experiments and understanding in science fiction differ in one important respect: While the former aim at what I shall call “physical understanding”, science fiction novels typically have “existential understanding” as their target. (shrink)

He describes his position as "neo-Carnapian", i.e. he is claiming that even if the question is meaningful, that doesn't mean it's worth looking into. He's probably right, in the sense that anyone can be right about a personal evaluative choice. And until I started questioning the belief that there is only one kind of physical process that could embody consciousness, I felt the same way myself. But the point about this thought experiment is that the current state of cognitive (...) science offers us two possible candidates for the embodiment of mind. And as Bickle points out, it seems like nothing we can imagine discovering in the future could settle this problem one way or the other. If this is true, this means that, strictly speaking, all this talk about being on the verge of a scientific understanding of consciousness is hype: No matter how close we get to solving the Chalmersian easy problems, we are getting nowhere nearer to solving the hard problem. If this is true, Cognitive Scientists ought to change their description of what they are doing, even if it cuts back on publicity and grant money. But I don't want to believe this, and I think the only way to avoid believing this is to discover the presuppositions that compel this belief, and see if we can change them. It's a dirty little job, but somebody has to do it, and philosophers seem less unqualified to attempt it than anyone else. Note, however, that I am not claiming we can use a thought experiment all by itself to find the answer, the way Searle claimed that the Chinese Room experiment supposedly proved that a computer couldn't be conscious. As RONALD LEMMEN points out, the fact that we can imagine something doesn't tell us anything about the world, only about our concepts of the world. Remember that the conclusion of my thought experiment was a question, not an answer. My only goal is to help clarify the question. (shrink)

The ArgumentIn this paper I present and argue for a model of conceptual development in science and apply it to the transition from classical to modern physics associated with Einstein. The model claims a continuous and rational transition between incompatible subsequent conceptual systems in mathematical science and explains its mechanism. The model was developed in a study of the transition from preclassical to classical mechanics. I argue for a strong structural analogy between the transition from preclassical to classical mechanics (...) on the one hand and from classical to modern physics on the other. The first transition is briefly sketched here by reference to Galileo and his disciples; in the second transition Planck and Lorentz on the one hand and Einstein on the other play the respective roles.A detailed and documented reconstruction of the transition from preclassical to classical mechanics on the basis of this model has already been published and is only briefly referred to in the paper. The transition from classical to modern physics is portrayed here much more extensively—though of course merely in broad brush strokes. Einstein–s role in this transition is reconstructed in the light of a conceptualization of his scientific knowledge as an active structure of thought, shaped by his intellectual experience. In this way, the development of his individual thinking is shown to be part of the overall process of conceptual transformation from classical to modern physics. The reconstruction sketched in this paper is to be considered as a proposal to be substantiated, reformed, and improved by future detailed studies. (shrink)

This paper is a study of the mental environment of the Newtonian conception of attraction in the case of George Cheyne, M.D. , physician of the early 18th century and author of a number of popular medical works. It traces the growth of his notions of a spiritual attraction between God and his creatures and between the creatures themselves, and the relation of these ideas both to his use of the Newtonian model of short-range attraction, and to his conception of (...) the creatures as reflections of the divine essence. The paper contends that the development of these aspects of Cheyne's thought harmonizes with the changing pattern of his life, and that this harmony is expressed by his general technique of reasoning by analogy between the various spheres of experience. (shrink)