David Bloor et la contingence des sciences formelles
Explorer les conceptions inévitabilistes versus contingentistes des preuves et résultats mathématiques...
En s'appuyant sur les propositions pionnières de Bloor et sur des comparaisons entre sciences formelles et empiriques
Ces Journées d’étude visent à discuter une thèse originale soutenue par le célèbre sociologue et philosophe des sciences David Bloor à propos des mathématiques : la thèse selon laquelle les preuves et les résultats mathématiques (et logiques) sont contingents, dans le même sens et pour les mêmes raisons que les justifications et les résultats empiriques mis en jeu dans les sciences de la nature.
Cette thèse, qui tranche avec la conception dominante des mathématiques comme royaume de la nécessité, a été introduite par Bloor dès les années 1970, puis développée par lui dans un certain nombre de travaux ultérieurs, mais est restée très largement ignorée au sein de la communauté des philosophes des mathématiques et plus largement des sciences. Même Ian Hacking, internationalement reconnu comme celui qui a le premier introduit et conceptualisé, au tournant des années 2000 en philosophie des sciences empiriques, l’opposition entre les conceptions « contingentistes » et « inévitabilistes » des résultats établis par les sciences de la nature, et qui s’est par la suite lui-même penché sur l’application de cette opposition au cas des mathématiques, semble ignorer les propositions « contingentistes » pionnières de Bloor à propos des sciences formelles (Bloor lui-même n’utilise pas le lexique hackinguien du « contingentisme » mais ses thèses se laissent très naturellement reconceptualiser en ces termes).
Cette situation interroge. Elle est d’autant plus regrettable que les analyses et arguments de Bloor appliqués aux mathématiques et à la logique, très élaborés et développés avec rigueur, s’avèrent, à divers égards significatifs, structurellement similaires à ceux que Hacking et ses successeurs ont appliqué à la physique, à la biologie, ou à d’autres sciences empiriques, ce qui suggère des rapprochements potentiellement féconds, d’un point de vue épistémologique, entre sciences formelles et sciences empiriques (par exemple, la question et les difficultés d’une mathématique « alternative » présentent des parentés essentielles avec celles d’une physique « alternative »).
La philosophie des sciences a tout à gagner à engager une discussion systématique et approfondie des propositions « contingentistes » de Bloor à propos des mathématiques plutôt que de les ‘traiter comme inexistantes’. Le récent développement de la « philosophie des pratiques mathématiques » constitue un contexte propice à cette discussion.
Les journées d’étude discuteront en détails les propositions de Bloor avec la volonté d’engager des comparaisons instructives entre sciences formelles et sciences de la nature. Du point de vue de ces comparaisons, les compétences diversifiées des membres des Archives H. Poincaré dans les domaines de la philosophie et de l’histoire des mathématiques et de la logique d’une part, des sciences de la nature d’autre part, seront mises à profit pour aborder de manière pluridisciplinaire le problème de la contingence/inévitabilité dans les sciences.
----
David Bloor and the contingency of the formal sciences
Exploring inevitabilitist versus contingentist views of mathematical proofs and results…
Relying on Bloor’s pioneering proposals and on comparisons between the formal and the empirical sciences
The conference will address an original thesis about mathematics (and logic) articulated by the renowned sociologist and philosopher of science David Bloor: namely, the thesis that mathematical (and logical) proofs and results are contingent—in the same sense and for the same reasons that, according to Bloor, the empirical arguments and results of the natural sciences are contingent.
The inevitabilist / contingentist (I/C) issue concerning scientific results was first formulated in these terms within the philosophy of the empirical sciences by Ian Hacking around the turn of the 2000s. Since then, it has been explored by a number of meta-analysts of science, but applied almost exclusively to the natural sciences. Yet as early as in the 1970s, Bloor – inspired by Wittgenstein – can be credited with having provided a systematic and powerful conceptual framework, applicable both to the natural and the formal sciences, that, although articulated in a “social” rather than a “contingentist” idiom, proves remarkably valuable for illuminating the I/C issue. Within this framework, Bloor’s position can readily be reformulated as a broadly scoped contingentism. Applied to the proofs and results of the formal sciences, this contingentism stands in sharp contrast to the dominant conception of mathematics as the “realm of necessity”. After the 1970s, Bloor further developed this position in several subsequent works. Yet this part of Bloor’s work has remained largely overlooked by philosophers of mathematics and, more broadly, by philosophers of science.
This neglect is regrettable. Bloor’s elaborate and rigorously argued analyses of the I/C issue as applied to mathematics and logic turn out, in several significant respects, to be structurally similar to analyses later developed by Hacking and his followers with regard to physics, biology, and other empirical sciences. This parallel strongly suggests potentially fruitful connections and epistemological cross-fertilizations between the philosophy of the formal and of the empirical sciences. For example, the question and challenges related to an “alternative mathematics” exhibit essential structural similarities with those related to an “alternative physics.”
Philosophy of science—broadly conceived to include mathematics and logic—has much to gain from engaging systematically and thoroughly with Bloor’s contingentist proposals, rather than treating them as if they did not exist. The recent development of the “philosophy of mathematical practice” provides a particularly favorable context for such a discussion.
The aim of the conference, then, is to discuss Bloor’s contingentist analyses, with a view to engaging in instructive comparisons between the formal sciences and the natural sciences.
The conference is part of the ongoing research project, “MultiScienceS”, launched in 2019 under the direction of Léna Soler (https://poincare.univ-lorraine.fr/fr/multisciences-une-autre-science-est-elle-viable). The project is carried out by an interdisciplinary team of researchers of various nationalities.
Tuesday, October 7th – DAVID BLOOR
8h30 WELCOME
8h45-9h - Léna SOLER: Opening
9h-10h Paul ERNEST: David Bloor’s Philosophy of Mathematics and the Beliefs of Working Mathematicians
10h-11h Léna SOLER: Bloor, Pioneer of Contingentism. Inevitabilist strategies about mathematics and logic, and their analogues in the natural sciences
11h-11h15: BREAK
11h15-12h15 Jean Paul VAN BENDEGEM: The Singular and the Plural in the Philosophy of Mathematics
12h15-13h15 Michael J. BARANY: The Contingency of Remedial Mathematics
13:15 – 14:30 LUNCH
14h30-15h30 Baptiste MÉLÈS: Do Computer-Assisted Proofs Change the Game for Mathematical Contingentism?
15h30-16h30 Bart van KERKHOVE and Sander POULIART: Bloor vs Heintz vs Restivo on and in the Sociology of Mathematics
16h30-17h. General discussion
DINER
Wednesday, October 8th – BEYOND BLOOR
8h30-9h30 Roy WAGNER: Contingency in the History of Euclidean Geometry
9h30-10h30 José Antonio PÉREZ-ESCOBAR and Colin Jakob RITTBERG: Petrification in Contemporary Set Theory: The Multiverse and the Later Wittgenstein
10h30-10h45 BREAK
10h45-11h45: Andrew ARANA: Contingency in the Boundaries of Mathematical Disciplines
11h45-12h45: Franci MANGRAVITI: In Defense of the Notion of Alternative Mathematics
12h45-13h15 General discussion
Sjoerd ZWART (Delft, University of Technology) will act as chair throughout the whole conference
Andrew ARANA, Archives Henri-Poincaré—PReST (UMR 7117), Université de Lorraine
Contingency in The Boundaries of Mathematical Disciplines
How are the boundaries of mathematical disciplines drawn? How do we distinguish arithmetic from geometry, or topology from analysis? Are the boundaries between these disciplines part of how mathematical nature is carved at the joints, as the inevitabilist would have it? Or is their drawing an activity of temporally-situated agents responding to their material and scientific conditions, as the contingentist would have it? In this talk, I will discuss these questions.
Michael J. BARANY, University of Edinburgh
The Contingency of Remedial Mathematics
A critical rhetorical and conceptual feature of Bloor's contingentist account of mathematical knowledge was a social theory of taken-for-granted examples of elementary mathematics. It is well known that elementary mathematics has a complex and consequential relationship to mathematics and formal sciences writ large, often confounding or misleading. I will develop a small but significant twist to Bloor's approach that reframes the relationship between elementary and less-elementary mathematics by focusing on the situated social production of epistemic closure. In particular, social processes of remediation can be identified as constitutive points of practical and conceptual continuity across different forms and contexts of mathematics. Bloor identified the social contexts of agreeing to the unicity and even self-evidence of mathematical claims as critical sites for the manifestation of social power and interests. A remedial view extends this insight by understanding closure to be a perpetually provisional and unfinished facet of mathematical epistemology. This permits a contingentist account of the relationship between settled and creative mathematics, while also accounting for the social production and acceptance of appearances of mathematics to be inevitable. I relate these analyses to Bloor's empiricist commitments and his understanding of formality, informality, and the relationship between them.
Jean Paul van BENDEGEM, Vrije Universiteit Brussel – Centre Leo Apostel (CLEA)
The Singular and the Plural in the Philosophy of Mathematics
Many philosophers and mathematicians will agree that changing the focus from mathematical theories, especially foundational theories, to what mathematicians do in their daily work has been an important development. There is, however, a highly curious feature that may seem quite innocent but, as I will argue, is extremely important, and that is that the label for this development uses the singular: the history and philosophy of mathematical practice. Not practices (as I prefer and claim it should be). My defence of the plural consists of another look at (a) one of the favourite examples of David Bloor, namely modus ponens, (b) the role of contradictions, calling in Ludwig Wittgenstein (and thereby Bloor as well), and (c) the status of infinity, a concept that in itself needs the plural. Present in the background, Graham Priest’s dialetheism – the view that there are true contradictions in the world itself, not merely in our theories – will serve as a test case, as it represents a rather extreme position (though Priest himself probably would stick to the singular).
Paul ERNEST, University of Exeter
David Bloor's Philosophy of Mathematics and the Beliefs of Working Mathematicians
A key tenet of David Bloor's philosophy of mathematics is that the beliefs of mathematicians must be explained, even if they correspond to the widely accepted dogmas of the absolute certainty of mathematical knowledge and of the objective existence of mathematical objects (Platonism). Bloor argues that explanations of such beliefs should be (1) causal, concerned with the conditions which bring about the beliefs; (2) impartial with respect to their truth and falsity; (3) symmetric in explaining both true and false beliefs.
This paper argues that these epistemic and ontic dogmas, irrespective of their truth or falsity, can be partly explained by their widespread acceptance as values. The corresponding beliefs should be seen as located in axiology and not epistemology or ontology. Mathematicians are recruited into the social practices of mathematics, and these come with established modes of working as well as metamathematical beliefs and values.
However, the claim is not that these dogmas are near-arbitrary; held in place solely by institutional decisions. There is a strong rational basis for these beliefs and values, because they are either true or nearly true. Mathematical knowledge is well justified because of proofs and successful applications. Mathematical objects are enduring entities that preexist the formation of mathematicians and continue in their existence beyond them. However, the objects of mathematics can be conceived as cultural instead of Platonic entities. Likewise, mathematical knowledge endures but need not be understood as based on metaphysical necessity. It can also be seen as based on social institutions imposing necessity, based on a deontological ‘must’.
Bloor’s arguments about the explanations of ontic and epistemic beliefs are independent of the epistemological and ontological assumptions of the status of mathematical knowledge and the nature of mathematical objects.
Bart van KERKHOVE and Sander POULIART, Centre Leo Apostel, Vrije Universiteit Brussel
Bloor vs Heintz vs Restivo on and in the Sociology of Mathematics
This paper will delve into the contributions of two lesser-known proponents of a social theory of mathematical knowledge. We shall put their accounts in the wider context of the field, compare their basic tenets to those of David Bloor so as to position them towards it, and then also assess whether and to what extent they give or leave more or less room for contingency in mathematics.
The first of these alternative accounts is that by the German scholar Bettina Heintz. Flowing from systems theory, it aspires to bridge contrasting sociological and philosophical concerns by formulating a general socio-historical explanation for the apparent universality and inevitability with which mathematical knowledge comes to us, through proof. At its core stands the idea that proof production is not mainly aimed at establishing certainty, but rather at facilitating proper communication, namely with a view to enhancing the badly needed trust in mathematical results. This position is better understood once its pragmatic nature is accepted, as what above all seems to count for working mathematicians is whether or not purported results can be relied upon for further research.
The second sociological account that we shall look into is that by the American sociologist Sal Restivo. Borrowing a core idea of the controversial German social critic Oswald Spengler, namely that different cultures are utterly incommensurable, and, accordingly, also have their very own conception of number, Restivo has developed a theory of 'mathematical sociologism'. It essentially says that mathematical production requires the use, and prior or simultaneous development, of conceptual tools, whereby one adopts learnt techniques as well as personal skills essentially as a member of different social groups. As a result, all mathematical 'things', like non-material things or things experienced in general (including talk, persons, minds, cognition) are constitutively social.
Franci MANGRAVITI, ETH Zurich
In Defense of the Notion of Alternative Mathematics
The philosophy of mathematical practice has done much work to unearth ways in which much of the standard picture of mathematics as a uniform monolith is built on questionable assumptions, simplifications, and erasures. Furthermore, the expressiveness of set theory and the rise of metamathematical methods have made it seemingly possible to encompass all kinds of alternatives within a single framework. Together, these two factors put pressure on the very notion of alternativeness - and thus, on the idea that mathematics could be contingent - not, as in the old days, from the perspective of there only being one ‘right’ mathematics, but rather from the perspective of mathematics already being as ‘open’ as possible, and a focus on alternatives unwarrantedly contributing to old-fashioned stereotypes. In this paper, I push back against this by arguing that the very possibility of constructive structural critiques of mathematics depends on alternatives being conceived in a stronger sense than the liberal and reductionist narratives can allow.
Baptiste MÉLÈS, CNRS, Archives Henri-Poincaré—PReST (UMR 7117), Université de Lorraine
Do Computer-Assisted Proofs Change the Game for Mathematical Contingentism?
Far from being a secondary point in David Bloor's argument, contingentism in mathematics is its cornerstone. One might think that the mechanization of mathematical proofs by proof assistants has changed the game by giving mathematics a new form of necessity. However, we will see that Bloor's arguments have both as much and as little reason to hold: other forms of mathematics are still possible, but sociological empiricism is still not proven.
José Antonio PÉREZ-ESCOBAR, Department of Logic, History and Philosophy of Science, UNED, Madrid
Colin Jakob RITTBERG, Centre Leo Apostel, Vrije Universiteit Brussel
Petrification in Contemporary Set Theory: The Multiverse and the Later Wittgenstein
As Bloor’s contingentist sociology of mathematics — rooted in Wittgenstein’s later philosophy — reminds us, choices in mathematics are historically situated. In this talk we follow up on the idea that these choices, which are contingent by nature, can solidify into normative demands. We argue that Wittgenstein’s notion of petrification can be used to explain this solidification. We focus on phenomena in advanced mathematics, thereby extending the debate about mathematical petrification by pushing beyond its current diet of examples of a very basic mathematical nature. Second, we analyze current disagreements on the absolute undecidability of CH under the notion of petrification. We make use of hinge epistemology to argue that contemporary construction techniques for set-theoretic models in which the Continuum Hypothesis holds and those in which it fails have petrified into the normative demand that CH remain undecidable. This argument draws on and enriches the arguments put forth by set theorist Joel David Hamkins.
Léna SOLER, Archives Henri-Poincaré—PReST (UMR 7117), Université de Lorraine
Bloor, Pioneer of Contingentism. Inevitabilist Strategies about Mathematics and Logic, and their Analogues in the Natural Sciences
This reflection pursues a threefold objective. First, to reconstruct David Bloor’s position on mathematics and logic as a form of “contingentism” (C), opposed to “inevitabilism” (I), in the senses introduced by Hacking in philosophy of science at the turn of the 2000s. Bloor can naturally be reconceptualized as a radical contingentist about science, including about what is usually regarded as the “realm of necessity”, namely mathematics and logic, especially proofs and results. Under this reconceptualization, we realize that already in the first 1976 edition of Knowledge and Social Imagery, Bloor had identified and masterfully discussed most of the conceptual and argumentative difficulties of the I/C issue, including many inevitabilist strategies commonly employed to dismiss or neutralize candidates for alternative mathematics – thereby maintaining the standard status of mathematics as inevitable, if not necessary. This invaluable Bloorian contribution, however, has gone largely unheeded by philosophers of science, including philosophers of mathematics. While the “strong programme” has been widely debated in relation to the natural sciences, the Bloorian contingentist analyses of mathematics and logic contained in it have, for their part, largely been treated as ‘nonexistent’.
Against this background, I will begin by specifying the main features of Bloor’s contingentism. Then, I will characterize in greater detail the main inevitabilist strategies directed at ingredients of mathematics and logic that Bloor systematically identified and critically discussed – this is my second objective. My third will be to compare the previous strategies, as applied to the formal sciences, with the inevitabilist strategies applied to the empirical sciences that have been brought to light in the post-Hacking literature devoted to the I/C debate—a debate that has so far been almost exclusively focused on the natural sciences while neglecting the formal ones. The comparison will reveal striking structural analogies, thereby showing the transdisciplinary character of the strategies Bloor had singled out at an early stage.
Roy WAGNER, ETH Zurich
Contingency in the History of Euclidean Geometry
In current historiography, attempted historical proofs of the parallel postulate are presented as inevitably wrong due to the existence of non-Euclidean models obeying Euclid's other axioms. I argue that this approach is committed to an inevitabilist view of mathematics and that under a suitable historical interpretation, some of these proofs may be as good as many well-established Euclidean proofs. I then argue that this historical interpretation articulates a contingent alternative mathematics that is irreducibly different and as good as current mathematics. I conclude by framing both current and Greek geometries as contingent on their distinct socio-cultural and institutional historical circumstances. The upshot is that mathematics is no less contingent than the underlying historical circumstances.
Scientific Committee
- Léna Soler, Université de Lorraine
- Andrew Arana, Université de Lorraine
- Sjoerd Zwart, University of technology, Delft
Organizing Committee
- Léna Soler, Université de Lorraine
- Rémi Blondel, Université de Lorraine
- Mamadou Lamine Ngom, Université de Lorraine
With the support of
- Archives Henri-Poincaré - Philosophie et Recherches sur les Sciences et les Technologies (AHP-PReST)
- Conseil scientifique de l’Université de Lorraine (CLCS)
- Maison des Sciences de l'Homme Lorraine (MSHL)
- Centre National de la Recherche Scientifique (CNRS)
- UFR de philosophie, Université de Lorraine
- ANR Mathematical Hygiene – MATHY pilotée par Andrew Arana
- Instituts de Recherche sur l’Enseignement des Mathématiques (IREM)









