Marco Buzzoni

Hempel’s account of thought experiments has been discussed only by a very few authors and, for the most part, with rather cursory remarks. Its importance, however, is not only historical, but also systematic theoretical, because it involves the distinction between discovery and justification, a main pillar of neopositivistic philosophy of science. Hempel raised the question whether thought experiments constitute a methodological component of scientific research or, on the contrary, are merely a heuristic-psychological device for obtaining and/or transmitting new ideas. While conceding a few exceptions in the natural sciences, he argued that thought experiments always have a heuristic character in the social sciences. There is however a fundamental tension in Hempel’s conception of thought experiments, between the thesis of methodological monism and the neopositivistic dichotomy discovery/justification. On the one hand, on the basis of the unity of scientific method, Hempel admits a difference only in degree between the natural and the human sciences, but on the other hand, he draws a principled distinction between thought experiments of the human sciences (which have only a greater or lesser heuristic value) and those of the natural sciences (which may have also a cognitive-justificatory value). If one assumes the unity of method in the minimal sense in which no scientific knowledge can renounce intersubjective controllability, this tension can be removed either by rejecting the discovery/justification dichotomy or by interpreting it differently. Here, following the second path, two senses of the dichotomy are distinguished, one of which must be accepted, while the other rejected. This removes the internal tension in Hempel’s conception of thought experiments and suggests the thesis that any plausible thought experiment, both in the natural and the human sciences, must already contain some justification, implicit or explicit, of the theoretical hypotheses that they formulate.

Der Neue Experimentalismus musste sich angesichts seines Gegensatzes zwischen experimentellen Praktiken und grundlegenden Theorien mit dem Problem der Beziehung zwischen der Einmaligkeit der ersteren und der Allgemeinheit der letzteren auseinandersetzen. Andere Autoren (von Charles A. Baylis und Nelson Goodman bis Catherine Elgin) haben das Konzept der Exemplifikation verwendet, um die Beziehung zwischen partikulären und universellen/allgemeinen Begriffen oder Gesetzen zu klären. Es stellt sich jedoch die Frage, ob sie zwar einen Gesichtspunkt andeuten, der neue Aspekte des Problems beleuchten kann, das Problem selbst aber nicht lösen. In diesem Artikel wird auf der Grundlage von Überlegungen, die an anderer Stelle entwickelt wurden, sowie in Anlehnung an eine Anregung von Aristoteles vorgeschlagen, den Begriff der Exemplifikation mit dem Problem der Induktion und der Abduktion zu verknüpfen, die hier als Bezeichnung für eine Vielzahl methodischer Verfahren verstanden werden, die darauf abzielen, eine kognitive Beziehung zwischen der Reproduzierbarkeit wissenschaftlicher Begriffe oder Gesetze und der Konkretheit, der Lokalität und dem situierten Charakter experimenteller Praktiken herzustellen. Eine notwendige Voraussetzung für die Lösung des durch diese Beziehung aufgeworfenen Problems ist die Unterscheidung zwischen zwei Bedeutungen − einer reflexiv-transzendentalen und einer genetisch-methodologischen − des Begriffspaares Entdeckung/Rechtfertigung. Dies wirft gleichzeitig Licht auf das Problem der Induktion sowie auf das Problem des Verhältnisses zwischen der Universalität wissenschaftlicher Gesetze und dem stets lokalen und situierten Charakter experimenteller Praktiken. Der letzte Teil des Artikels zeigt, wie diese Schlussfolgerungen auch für Gedankenexperimente gelten, indem auf John Nortons Auffassung eingegangen wird.

Nella sua straordinaria opera scientifica, Franco Selleri si è sempre opposto alla rinuncia alla comprensione della struttura della realtà e della natura degli oggetti fisici, che egli considera come l’elemento caratterizzante delle principali teorie della fisica del Novecento e che è stata stigmatizzata da Karl Popper come tesi della “fine della strada in fisica”. Sin dalla fine degli anni ’60, egli ha sviluppato quella riflessione critica nei confronti delle teorie fondamentali della fisica moderna, in particolar modo della teoria delle particelle elementari e della meccanica quantistica, e in un secondo tempo delle teorie relativistiche, che contraddistingue il suo programma di ricerca. Nel corso della sua intensa e infaticabile attività scientifica, Selleri è entrato in proficuo contatto con molti grandi fisici e filosofi della scienza, instaurando un intenso dialogo critico con Louis de Broglie, John Bell e Karl Popper. Le sue originali e non convenzionali ricerche lo hanno portato a risultati significativi non solo nell’ambito dei fondamenti della fisica, ma anche della storia e della filosofia della fisica. Per questo abbiamo voluto dedicare un numero speciale di Isonomia al nostro impareggiabile amico e collega, sia per la sua passione instancabile e la sua profonda conoscenza dei fondamenti formali, concettuali e filosofici delle teorie della fisica contemporanea, sia e forse ancor più come maestro di una prospettiva perennemente critica che egli ha sempre seguito e proposto con particolare rigore ed estrema determinazione.

This book offers the most complete and up-to-date overview of the philosophical work of Evandro Agazzi, presently the most important Italian philosopher of science, and one of the most influential in the world. Scholars from seven countries explore his contributions in areas ranging from philosophy of physics and general philosophy of science to bioethics, philosophy of mathematics and logic, epistemology of the social sciences and history of science, philosophy of language and artificial intelligence, education and anthropology, metaphysics, and philosophy of religion. Agazzi developed a complete and coherent philosophical system, anticipating some of the turns in the philosophy of science after the crisis of logical empiricism and exerting an equal influence on continental hermeneutic philosophy. His work is characterized by an original synthesis of contemporary analytic philosophy, phenomenology, and classical philosophy, including the scholastic tradition, and these threads are reflected in the different backgrounds of the contributors to this book. While upholding the epistemological value of science against scepticism and relativism, Agazzi eschews scientism by stressing the equal importance of non-scientific forms of thought, such as metaphysics and religion. While defending the freedom of research as a cognitive enterprise, he argues that as a human and social practice it must nonetheless respect ethical constraints.

With reference to an already existing and relatively widespread use of the expression in question, mathematical “thought experiments” (“TEs”) involve mathematical reasoning in which visualisation plays a relatively more important role. But to ensure an unambiguous and consistent use of the term, certain conditions have to be met: (1) Contrary to what has happened so far in the literature, the distinction between logical-formal thinking and experimental-operational thinking must not be ignored; (2) The separation between the context of discovery and the context of justification is to be rejected, at least in one of the main senses in which it was defended by the logical empiricists and Popper (this excludes any position which, ascribing to mathematical TEs only a heuristic role, regards them an intermediate step to attain more traditional forms of rigour); (3) The distinction between mathematical TEs and formal proofs must be regarded as one of degree, and not as a qualitative one, although this distinction may be used in a de facto way for particular or local purposes.

In the last decades it has become clear that medicine must find some way to combine its scientific and humanistic sides. In other words, an adequate notion of medicine requires an integrative position that mediates between the analytic-reductionist and the normative-holistic tendencies we find therein. This is especially important as these different styles of reasoning separate “illness” (something perceived and managed by the whole individual in concert with their environment) and “disease” (a “mechanical failure” of a biological element within the body). While the demand for an integrative view has typically been motivated by ethical concerns, we claim that it is also motivated, perhaps even more fundamentally, by epistemological and methodological reasons. Evidence-based bio-medicine employs experimental and statistical techniques which eliminate important differences in the ways that conscious humans evaluate, live with, and react to disease and illness. However, it is precisely these experiences that underpin the concepts and norms of bio-medicine. Humanistic disciplines, on the other hand, have the resources to investigate these experiences in an intersubjectively testable way. Medicine, therefore, cannot afford to ignore its nature as a human science; it must be concerned not only with disease and illness, but also with the ways in which patients as persons respond to malady. Insofar as attitudes and expectations influence the criteria of illness and disease, they must be studied as part of the genuine subject matter of medicine as a human science. In general, we urge that this is a necessary step to overcome today's trend to split evidence-based and clinical medicine.

Elsewhere I have tried to provide the justification of both the irreducible distinction of science and philosophy and their inevitable complementarity. Unlike empirical science, philosophy has no limit whatever as far as its possible objects are concerned. To say that there is no limit whatever to the possible objects of philosophy is to say that, strictly speaking, it has no object at all and must find its object outside itself, that is, in common sense knowledge and the natural and human sciences. Against the background of this conception, the paper argues that philosophy of science, as a critical reflection on common sense knowledge and the natural or human sciences, inherits from philosophy in general this two-faced Janus nature, which in the philosophy of science shapes the epistemological status of the discipline in an even more prominent way. To show this in detail, the paper enunciates eleven theses that derive from the intimate connection of unity and distinction that exists between philosophy of science on the one hand and the particular and specialized scientific knowledge on the other.

Since the beginning of the twentieth century, prominent authors including Jean Piaget have drawn attention to Edmond Goblot’s account of mathematical thought experiments. But his contribution to today’s debate has been neglected so far. The main goal of this article is to reconstruct and discuss Goblot’s account of logical operations (the term he used for thought experiments in mathematics) and its interpretation by Piaget against the theoretical background of two open questions in today’s debate: (1) the relationship between empirical and mathematical thought experiments and (2) the question of whether mathematical thought experiments can play a justificatory function in proofs. The main corollary of this analysis is that Piaget’s interpretation is seriously flawed and insufficiently appreciative of important theses of Goblot’s account. First, Goblot can be easily defended against Piaget’s main criticism, and second, Goblot developed ideas about mathematical thought experiments that still deserve attention.

Since the beginning of the twentieth century, prominent authors including Jean Piaget have drawn attention to Edmond Goblot’s account of mathematical thought experiments. But his contribution to today’s debate has been neglected so far. The main goal of this article is to reconstruct and discuss Goblot’s account of logical operations (the term he used for thought experiments in mathematics) and its interpretation by Piaget against the theoretical background of two open questions in today’s debate: (1) the relationship between empirical and mathematical thought experiments and (2) the question of whether mathematical thought experiments can play a justificatory function in proofs. The main corollary of this analysis is that Piaget’s interpretation is seriously flawed and insufficiently appreciative of important theses of Goblot’s account. First, Goblot can be easily defended against Piaget’s main criticism, and second, Goblot developed ideas about mathematical thought experiments that still deserve attention.

Despite the many turns that philosophy of technology has undergone in recent decades, the question of the nature and limits of technological determinism (TD) has been neglected, because it was considered as solved and overcome, and therefore not worth further discussion. This paper once again raises the problem of TD, by trying to save the opposing, but complementary elements of truth of the two main forms of TD that I shall call “nomological” and “normative”: (a) technology is all-pervasive and has an inexorable capacity for extending itself into every field of human life, and (b) we have a capacity to counteract and orient technology, at least in some measure. In order to reconcile these seemingly inconsistent claims, the key move for my argument is a brief analysis of the notion of scientific experiment from the perspective of the distinction between the context of discovery and the context of justification. As a result, two senses of technology are distinguished, which I shall call respectively “reflective” and “methodological.” From the point of view of this distinction, the all-pervasiveness and inexorability of technology and the in principle irreducibility of human persons to technology—which nomological and normative TD assert dialectically one against the other—can be reconciled. Among other things, this requires the rejection (in one fundamental sense) of the widely held assumption, made both by nomological and normative TD, that technology is a cultural field whose contents can be neatly separated from the rest of human culture. This thesis should be replaced by the more qualified claim of the reflective unity and the methodological multiplicity of technology.

The main purpose of this paper is to investigate some important aspects of the relationship between thought experiment and computer simulation, from the point of view of real experiment. In the first part of this paper, I shall pass in critical review four important approaches concerning the relationship between TE and CS. None of these approaches, though containing some important insights, has succeeded in distinguishing between CS and TE, on the one hand, and REs, on the other. Neither have they succeeded in distinguishing TEs and REs. In Sect. 5, the paper briefly outlines an account of CSs as compared with TEs that takes REs as a central reference point. From the perspective of the analysis of the empirico-experimental intensions of the concepts of TE, CS, and RE—considering their empirical content and actual performance within a discipline—the attempts to find a distinction in logical kind between TEs, CSs and REs breaks down: for every particular characteristic of one of these notions there is a corresponding characteristic in the two others. From an epistemological-transcendental point of view, the only difference in kind between TEs and CSs consists in the fact that any simulation, even a computer one, involves a kind of real execution, one that is not merely psychological or conceptual. In TEs the subject operates concretely by using mental concepts in the first person; in contrast, real experiments and simulations involve an ‘external’ realisation. As shown in Sect. 6, this manifests itself in the higher degree of complexity often found in CSs as compared with TEs.

The first part of this paper discusses two important meanings of robustness and shows their essential connection with the notion of intersubjective reproducibility. As I shall maintain, robustness in both senses of the term is intimately connected with the notion of scientific experiment. This is the important element of truth of the mechanistic systems approach, which explains events as products of robust and regular systems and processes. In the second part of this paper I shall show that the concept of robustness of a mechanism, if applied to biological systems, is one-sided and incomplete without a heuristic˗methodical reference to final causes, even though the assumption of the teleological point of view is justified in biology only to the extent that we use it as a counterfactual artifice, capable of bringing to light causal relations which have a robustly reproducible content. In this way, the reflexive, typically human concept of purposefulness may be employed to investigate living beings scientifically, that is, in an intersubjectively testable and reproducible way, to discover mechanisms in living systems which are robust in both senses of the word.

The paper addresses the question of the nature and limits of philosophical thought experiments. On the one hand, experimental philosophers are right to claim that we need much more laboratory work in order to have more reliable thought experiments, but on the other hand a naturalism that is too radical is incapable of clarifying the peculiarity of thought experiments in philosophy. Starting from a historico-critical reconstruction of Kant’s concept of the “experiments of pure reason”, this paper outlines an account of thought experiments in philosophy that tries to reconcile the thesis of a principled difference between scientific and philosophical TEs with the position of a methodological naturalism that does not admit any difference in kind between the methods of science and of philosophy.

The conventional interpretation that Duhem condemned outright any type of thought experiment in Mach’s sense should be, at least in large part, rejected. There are some interesting remarks made by Mach and Duhem that suggest a very different reading. In this paper I shall take up and develop these remarks, which lead to the conjecture that Duhem’s criticism was not intended to be a complete rejection of thought experiments but a completion and supplement of Mach’s theory. Duhem, while retaining the core idea of Mach’s theory – according to which thought experiments cannot break free from the ultimate authority of real world experiments –, laid particular emphasis on the perils of thought experiment, which Mach had overlooked or, at least, underestimated.

The purpose of this article is to examine two important issues concerning the agency theory of causality: the charge of anthropomorphism and the relation of simultaneous causation. After a brief outline of the agency theory, sections 2–4 contain the refutation of the three main forms in which the charge of anthropomorphism is to be found in the literature. It will appear that it is necessary to distinguish between the subjective and the objective aspect of the concept of causation. This will lead, in section 5, to contrast two kinds of anthropomorphism, one which has been rightly rejected by modern science and one which is fully compatible with the objective reality of the causal processes. Finally, section 6 will apply the preceding considerations to simultaneous causation. On the one hand, in a basic sense, there can be no simultaneous causal relations. On the other hand, simultaneous causation arises when we consider the natural change by abstracting from the agent and from her/his projects of interven..

The paper outlines a critical history of the concept of TE from a broadly Kantian viewpoint. The thread of our discussion has been Kant's position on the nature of the a priori and how each neo-Kantian theory of TEs can be understood in terms of its own position on this issue. Section 2 examines some aspects of Kant's philosophy that are related to today's debate on TEs. Section 3 is devoted to the precursors of neo-Kantian accounts of TEs, with a special emphasis on Ørsted's account. This author wavers between two positions: sometimes he claims that TEs are merely the hypothetical aspect of REs while other times he assigns to them the capacity of determining a priori some fundamental laws of natural science. The latter position recalls the "material" aspect of the Kantian a priori, a notion which was abandoned by the philosophy of science at the end of the nineteenth century. This is probably the main reason Ørsted's point of view had no real influence on the historical development of the concept of TE and why some recent Kantian or neo-Kantian accounts of TE depart from Ørsted's concept of the a priori. I, on the other hand, have defended an interpretation of the a priori as purely functional by retaining the necessary and universal character of Kant's a priori while rejecting the material a priori, since content can be given only by experience. On this view, TE and RE are complementary in a sense similar to the complementarity of form and matter in Kant: TEs without REs are empty; REs without TEs are blind. On the other hand, Yiftach Fehige has defended a relativized and contingent notion of the a priori which has been recently advocated by many authors, notably by Michael Friedman. Unlike myself, Fehige rejects the universality and necessity of Kant's a priori but retains the idea that the a priori, as a constitutive element of experience, is endowed with material content that may be made explicit by thought experimentation.

Marco Buzzoni Gödel, Searle, and the Computational Theory of the (Other) Mind According to Sergio Galvan, some of the arguments offered by Lucas and Penrose are somewhat obscure or even logically invalid, but he accepts their fundamental idea that a human mind does not work as a computational machine. His main point is that there is a qualitative difference between the principles of the logic of provability and those of the logic of evidence and belief. To evaluate this suggestion, I shall first compare it with Searle’s concept of “intentionality”, and then introduce a distinction between two different senses of intentionality: a reflexive-transcendental sense and a positive (that is, historical empirical or formal logical) one. In the first of these senses, the nature of human reason is such that we have no idea how a real material system – or the corresponding formal one – could instantiate it. However, although this will turn out to be an important element of truth in Searle’s and Galvan’s conception, it does not exclude the opposite truth of Turing’s functionalism: because intentionality, intuition, vision or insight – taken in their reflexive-transcendental sense – are simply invisible to the scientific eye, a man and a machine (or a robot) that is and one that is not endowed with intentionality are de facto indistinguishable from a strictly scientific point of view. For this reason, we might eventually be entitled, or even — by the practical precautionary principle – morally obliged, to attribute minds to machines.

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.

Why, for such a long time, has there been no Kantian point of view among the most influential theories about thought experiments? The primary historical reason – the main trends in the philosophy of science have always rejected the existence of a priori knowledge – fits a theoretical reason. Kant oscillated between two very different views about the a priori: on the one hand, he attributed to it a particular content, whereas on the other hand he insisted on its purely formal character. The first interpretation of the a priori was one-sidedly developed by Ørsted and led to his untenable notion of thought experiment. The other interpretation, however, can be further developed into new Kantian theories of thought experiments in the natural sciences and in philosophy.

Within Popper's philosophy of science there is a tension between two different and opposite tendencies of thought: one consists in a decisive critique of the neopositivistic philosophy of science, the other preserves instead some assumptions of gnoseology and ontology of Wittgenstein's Tractatus. The attempt to resolve the tension between these two tendencies of thought constitutes the spring that has guided the internal development of Popperian epistemology, from the falsificationism of Die beiden Grundprobleme der Erkenntnistheorie and Logik der Forschung to the more recent theory of World 3. The thesis of a co-presence in Popper's thought of neo-positivistic and antíneopositivistic themes is here understood in a radical sense, which invests the gnoseological and ontological foundations of Popperian epistemology. The development of this thesis takes place by discussing the relevant literature of both the English and German linguistic area. Finally, the author has attempted to enucleate from Popperian epistemology those elements of thought that, if properly developed, would have allowed a re-reading in operational terms of the notion of scientific objectivity and would have made superfluous any Platonic theory of science, such as the Popperian theory of World 3, plagued by serious internal difficulties.

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

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

Thought experiments de facto play many different roles in biology: economical, ethical, technical and so forth. This paper, however, is interested in whether there are any distinctive features of biological TEs as such. The question may be settled in the affirmative because TEs in biology have a function that is intimately connected with the epistemological and methodological status of biology. Peculiar to TEs in biology is the fact that the reflexive, typically human concept of finality may be profitably employed to discover mechanical-experimental causal relations in all living beings—with the obvious caveat that we do not hypostatise and interpret this concept as an ontological quality, since this would land one in an implicitly animistic, pre-Galilean view of nature. From a methodical point of view, the concept of finality is an essential assumption as well as a powerful heuristic tool in the practice of biology, that is, in the investigation of living beings in an intersubjectively testable and reproducible way