This article presents Tarski's Address at the Princeton Bicentennial Conference on Problems of Mathematics, together with a separate summary. Two accounts of the discussion which followed are also included. The central topic of the Address and of the discussion is decision problems. The introductory note gives information about the Conference, about the background of the subjects discussed in the Address, and about subsequent developments to these subjects.

L'abstraction mathématique consiste en la considération et la ma­nipulation d'opérations, règles et concepts indépendamment du contenu dont les nantissent des applications particulières et du rapport qu'ils peuvent avoir avec les phénomènes et les circonstances du monde réel. L'abstraction ma­thématique emprunte diverses voies. Le terme « abstraction » ne désigne pas une procédure unique, mais un processus général où s'entrecroisent divers pro­cédés employés successivement ou simultanément. En particulier, l'abstrac­tion mathématique ne se réduit pas à la subsomption logique. Je vais étudier comparativement (...) en quels termes les philosophes expliquent l'abstraction et par quels moyens les mathématiciens la mettent en œuvre. Je voudrais par là mettre en lumière les principaux processus de pensée en jeu et illustrer par des exemples divers niveaux d'intrication de techniques mathématiques récurrentes, qui incluent notamment la méthode axiomatique, les principes d'invariance, les relations d'équivalence et les correspondances fonctionnelles.Mathematical abstraction is the process of considering and ma­nipulating operations, rules, methods and concepts divested from their refe­rence to real world phenomena and circumstances, and also deprived from the content connected to particular applications. There is no one single way of per­forming mathematical abstraction. The term “abstraction” does not name a unique procedure but a general process, which goes many ways that are mostly simultaneous and intertwined; in particular, the process does not amount only to logical subsumption. I will consider comparatively how philosophers consi­der abstraction and how mathematicians perform it, with the aim to bring to light the fundamental thinking processes at play, and to illustrate by signifi­cant examples how much intricate and multi-leveled may be the combination of typical mathematical techniques which include axiomatic method, invariance principles, equivalence relations and functional correspondences. (shrink)

Ce livre résulte de recherches sur les transformations récentes d’un concept aussi vieux que la mathématique elle-même, celui de nombre réel. De l’analyse classique à l’algèbre « moderne » et de celle-ci à la théorie des modèles, on trace ici le parcours singulier d’une alliance réussie des mathématiques et de la logique. La structure algébrique de corps réel clos et la théorie élémentaire de cette structure conduisent à déplacer la frontière du champ d’intervention des concepts analytiques dans de nombreux problèmes.S’il (...) est possible de songer aujourd’hui à une philosophie des mathématiques, on ne pourra négliger le matériau ici présenté, l’auteur mettant en valeur les éléments qui invitent à repenser le rapport de cette science à la logique en qui, aujourd’hui, elle découvre pour ses multiples facettes une partenaire universelle. (shrink)

This article presents Tarski's Address at the Princeton Bicentennial Conference on Problems of Mathematics, together with a separate summary. Two accounts of the discussion which followed are also included. The central topic of the Address and of the discussion is decision problems. The introductory note gives information about the Conference, about the background of the subjects discussed in the Address, and about subsequent developments to these subjects.

Neurosciences and cognitive sciences provide us with myriad empirical findings that shed light on hypothesised primitive numerical processes in the brain and in the mind. Yet, the hypotheses on which the experiments are based, and hence the results, depend strongly on sophisticated abstract models used to describe and explain neural data or cognitive representations that supposedly are the empirical roots of primary arithmetical activity. I will question the foundational role of such models. I will even cast doubt upon the search (...) for a general and unified philosophical foundation of an empirical science. First, it seems to me hard to draw a global and coherent view from the innumerable and piecemeal neuropsychological experiments and their variable, and sometimes uneasily compatible or fully divergent interpretations. Secondly, I think that the aim of empirical research is to describe dynamical processes, establishing correlations between different sets of data, without meaning to fix an origin or to point to a cause, let alone to a ground. From the very scientific and philosophical point of view it is essential to distinguish between explanations, which provide correlations or, at best, causal mechanisms, and grounding, which involves a claim to some form of determinism. (shrink)