Our standard model-theoretic definition of logical consequence is originally based on Alfred Tarski’s (1936) semantic definition, which, in turn, is based on Rudolf Carnap’s (1934) similar definition. In recent literature, Tarski’s definition is described as a conceptual analysis of the intuitive ‘everyday’ concept of consequence or as an explication of it, but the use of these terms is loose and largely unaccounted for. I argue that the definition is not an analysis but an explication, in the Carnapian sense: the replacement (...) of the inexact everyday concept with an exact one. Some everyday intuitions were thus brought into a precise form, others were ignored and forgotten. How exactly did the concept of logical consequence change in this process? I suggest that we could find some of the forgotten intuitions in Bernard Bolzano’s (1837) definition of ‘deducibility’, which is traditionally viewed as the main precursor of Tarski’s definition from a time before formalized languages. It turns out that Bolzano’s definition is subject to just the kind of natural features—paradoxicality of everyday language, Platonism about propositions, and dependence on the external world—that Tarski sought to tame by constructing an artificial concept for the special needs of mathematical logic. (shrink)

In Section 1, the author argues that Bolzano does not have a Meinongian view of merely possible objects, not even in the context of his theory of intentionality. In section 2, it is argued that Williamson’s necessitist conception, according to which there is a merely possible golden mountain, was not anticipated by Bolzano. An eternalist reconstruction is rejected as well. The argument takes recourse to Bolzano’s semantics of temporal statements, which also underlies his argument for the eternity of substances and (...) makes it plausible to assume that Bolzano had a perdurantist view, according to which there are merely possible objects just in case there are actual objects whose generation is to be metaphysically explained, in terms of grounding, by recourse to a merely possible object’s being replaced by an actual object. Furthermore, it is argued that merely possible objects à la Bolzano are not substances, in his narrow sense of the term, and that his case for such objects in connection with his view of generation is less than convincing. However, section 3 argues that Bolzano’s conception combines with his view of substance to yield an interesting perdurantist conception of personal identity. (shrink)

This compelling reevaluation of the relationship between logic and knowledge affirms the key role that the notion of judgement must play in such a review. The commentary repatriates the concept of judgement in the discussion, banished in recent times by the logical positivism of Wittgenstein, Hilbert and Schlick, and the Platonism of Bolzano. The volume commences with the insights of Swedish philosopher Per Martin-Löf, the father of constructive type theory, for whom logic is a demonstrative science in which judgement is (...) a settled feature of the landscape. His paper opens the first of four sections that examine, in turn, historical philosophical assessments of judgement and reason; their place in early modern philosophy; the notion of judgement and logical theory in Wolff, Kant and Neo-Kantians like Windelband; their development in the Husserlian phenomenological paradigm; and the work of Bolzano, Russell and Frege. The papers, whose authors include Per Martin-Löf, Göran Sundholm, Michael Della Rocca and Robin Rollinger, represent a finely judged editorial selection highlighting work on philosophers exercised by the question of whether or not an epistemic notion of judgement has a role to play in logic. The volume will be of profound interest to students and academicians for its application of historical developments in philosophy to the solution of vexatious contemporary issues in the foundation of logic. ​. (shrink)

In this paper, I develop an argument against eternalism, which is similar to the widely discussed grounding problem for presentism. It has recently been argued by many that presentism should be rejected on grounds that its sparse ontology is not suited to underwrite the healthy dose of realism we all share about the past. My aim basically is to add a new twist to the debate, by showing that actually eternalists are no better off than their rivals. In particular, I (...) argue that the eternalist’s ontology does not have the appropriate shape to ground true propositions about the past. (shrink)

Dans les « Prolégomènes à la logique pure » de ses Recherches logiques , Husserl rend hommage aux deux premiers volumes de la Wissenschaftslehre de 1837 de Bernard Bolzano comme un « ouvrage qui […] surpasse de loin tout ce que la littérature mondiale a à offrir en termes de contributions systématiques à la logique ». Cet article porte sur le jeune Husserl comme lecteur du chef-d’oeuvre de Bolzano, visant ainsi à contribuer à une compréhension adéquate de certains aspects des (...) théories de Bolzano et de Husserl et de ce sur quoi portent ces théories. Je me concentrerai sur la question de savoir comment Bolzano en 1837 et Husserl autour de 1900 ont conçu les contenus des actes et états mentaux.Dans les sections 1 et 2, je fais état de la redécouverte de la WL de Bolzano au sein de l’École de Brentano, et en ce qui concerne le problème des représentations sans objets, j’endosse la défense de Bolzano par Husserl contre Twardowski. Dans les sections 3 et 4, je présente un aperçu de la théorie des propositions et des notions , et montre comment Husserl assimile le cadre conceptuel bolzanien dans ses RL. Tandis que Bolzano considère les propositions et les notions comme étant des objets abstraits sui generis, le jeune Husserl développe une conception des notions et des propositions en termes d’espèces. J’explique cette conception dans la section 5 et je la défends contre le dernier Husserl. La discussion la plus extensive et la plus détaillée d’une seule et unique thèse de la philosophie de la logique de Bolzano qu’on puisse trouver dans les livres et les articles publiés par Husserl de son vivant se trouve dans le dernier chapitre de ses RL. Le sujet de discussion, et la dernière section de cet article, est une affirmation courageuse, pour ne pas dire outrageuse de Bolzano qui, du moins pris au pied de la lettre, contredit tout simplement ce que la plupart des philosophes ont tenu pour acquis depuis Aristote. Les questions, soutient Bolzano, sont une espèce particulière de propositions, et donc leur vérité est susceptible d’être évaluée.In the “Prolegomena to Pure Logic” of his Logical Investigations Husserl praised the first two volumes of Bernard Bolzano’s Wissenschaftslehre of 1837 as “a work which … far surpasses everything that world-literature has to offer in the way of systematic contributions to logic”. This paper is about the early Husserl as a reader of Bolzano’s masterpiece, hoping thereby to contribute to a proper understanding of certain aspects of Bolzano’s and Husserl’s theories and of what those theories are about. I shall concentrate on the question how Bolzano in 1837 and Husserl around 1900 conceive of the contents of mental acts and states.In sections 1-2 I report on the rediscovery of Bolzano’s WL in the school of Brentano, and as regards the issue of objectless presentations, I endorse Husserl’s defence of Bolzano against Twardowski. In sections 3-4 I present an outline of Bolzano’s theory of propositions and notions and go on to show how Husserl assimilates the Bolzanian framework in his LI. While Bolzano takes propositions and notions to be sui generis abstract objects, the early Husserl develops a species conception of notions and proposition. I explain this view in section 5 and defend it against Husserl’s later self. The most extensive and most thorough discussion of a single contention in Bolzano’s philosophy of logic that can be found in any of Husserl’s books and articles published during his lifetime is contained in the last chapter of his LI. The topic of this discussion, and of the final section of this paper, is a courageous if not outrageous Bolzanian contention : questions, he claims, are a special kind of propositions and hence truth-evaluable. (shrink)

This essay presents a new interpretation of Bolzano's account of necessary truth as set out in ?182 of the Theory of Science. According to this interpretation, Bolzano's conception is closely related to that of Leibniz, with some important differences. In the first place, Bolzano's conception of necessary truth embraces not only what Leibniz called metaphysical or brute necessities but also moral necessities (truths grounded in God's choice of the best among all metaphysical possibilities). Second, in marked contrast to Leibniz, Bolzano (...) maintains that there is still plenty of room for contingency even on this broader conception of necessity. (shrink)

Throughout his career, Husserl identifies naturalism as the greatest threat to both the sciences and philosophy. In this paper, I explicate Husserl’s overall diagnosis and critique of naturalism and then examine the specific transcendental aspect of his critique. Husserl agreed with the Neo-Kantians in rejecting naturalism. He has three major critiques of naturalism: First, it (like psychologism and for the same reasons) is ‘countersensical’ in that it denies the very ideal laws that it needs for its own justification. Second, naturalism (...) essentially misconstrues consciousness by treating it as a part of the world. Third, naturalism is the inevitable consequence of a certain rigidification of the ‘natural attitude’ into what Husserl calls the ‘naturalistic attitude’. This naturalistic attitude ‘reifies’ and it ‘absolutizes’ the world such that it is treated as taken-for-granted and ‘obvious’. Husserl’s transcendental phenomenological analysis, however, discloses that the natural attitude is, despite its omnipresence in everyday life, not primary, but in fact is relative to the ‘absolute’ transcendental attitude. The mature Husserl’s critique of naturalism is therefore based on his acceptance of the absolute priority of the transcendental attitude . The paradox remains that we must start from and, in a sense, return to the natural attitude, while, at the same time, restricting this attitude through the on-going transcendental vigilance of the universal epoché. (shrink)

Through a detailed explication of Bernard Bolzano's semantics of natural kind terms, I elucidate why and to what extent he should be recognized as a remarkable anticipator of semantic externalism. Bolzano deals with kind terms in a brief sub-section of the first volume of his Theory of Science. He divides such terms into two sub-categories, roughly corresponding to organic and inorganic kinds. It is Bolzano's account of inorganic kind terms, such as ‘gold’, that confers on him the status of an (...) anticipator of semantic externalism. He argues that ‘gold’ may be used in a way such that the superficial attributes that language users associate with it merely serve to enable them to recognize its instances. They do not, however, constitute the idea designated by the term nor do they determine its extension. Instead, the term designates an idea representing gold's unknown inner attributes, which are causally responsible for its superficial attributes. (shrink)

Bernard Bolzano développe une théorie exhaustive et très élaborée des propositions comme entités structurées et composées de concepts. L’une de ses thèses principales consiste à dire que toutes les propositions ont en commun la même structure : « A – a – b ». Cet article examine le rôle que jouent les propriétés eu égard à cette thèse. Lorsque les propriétés figurent dans les théories sémantiques standards, elles sont généralement conçues comme des entités partageables, en d’autres mots, comme des universaux. (...) Je montre que Bolzano croyait que ce sont bien plutôt des propriétés particularisées qui tombent sous la représentation-prédicat d’une proposition. De là émerge une sémantique plutôt inhabituelle : une proposition de la forme [A – a – b] est vraie ssi une des propriétés particularisées qui se tiennent sous la représentation-prédicat [b] inhère au sujet de la proposition, c’est-à-dire l’entité dénotée par la représentation-sujet [A].Bernard Bolzano developed a highly elaborate and comprising account of propositions as structured entities composed of concepts. One of his main contentions was that all propositions share a common structure : “A – has – b”. The main part of my paper is a discussion of the role which properties play for this thesis and thus in Bolzano’s semantics. Where properties feature as semantic values in standard semantic theories they are conceived of as shareable entities, in other words, as universals. I show that it is particularised properties which Bolzano thought to be the entities standing under the predicate-ideas of propositions. With this idea, a rather uncommon semantic arises : a proposition of the form [A – has – b] will be true iff one of the particularised properties standing under the predicate-idea [b] inheres in the subject of the proposition, i.e. in the entity denoted by the subject-idea [A]. (shrink)

(2013). Bolzano on the Source of Necessity: A Reply to Rusnock. British Journal for the History of Philosophy: Vol. 21, No. 2, pp. 381-392. doi: 10.1080/09608788.2012.692661.

In a series of publications beginning in the 1980s, John Etchemendy has argued that the standard semantical account of logical consequence, due in its essentials to Alfred Tarski, is fundamentally mistaken. He argues that, while Tarski's definition requires us to classify the terms of a language as logical or non-logical, no such division is guaranteed to deliver the correct extension of our pre-theoretical or intuitive consequence relation. In addition, and perhaps more importantly, Tarski's account is claimed to be incapable of (...) explaining an essential modal/epistemological feature of consequence, namely, its necessity and apriority. Bernard Bolzano (1781-1848) is widely recognized as having anticipated Tarski's definition in his Wissenschaftslehre (or Theory of Science ) of 1837. Because of the similarities between his account and Tarski's, Etchemendy's arguments have also been extended to cover Bolzano. The purpose of this article is to consider Bolzano's theory in the light of these criticisms. We argue that, due to important differences between Bolzano's and Tarski's theories, Etchemendy's objections do not apply immediately to Bolzano's account of consequence. Moreover, Bolzano's writings contain the elements of a detailed philosophical response to Etchemendy. (shrink)

Bernard Bolzano offers a criterion of individuation for ideas, according to which ideas are distinct if and only if they represent different objects or are composed differently. It fails to individuate ideas that are both simple and fail to represent, in particular syncategorematic ideas and logical constants. However, Bolzano also provides the means to close this gap. He suggests that we can distinguish ideas if they are not substitutable for each other in propositions, which we can, in turn, distinguish in (...) terms of their truth-values. This paper explicates this suggestion and develops it into an improved individuation criterion for ideas: ideas also are distinct if we cannot replace them for one another in propositions salva veritate. (shrink)

Bolzano incorporated Kant's distinction between intuitions and concepts into the doctrine of propositions by distinguishing between conceptual (Begriffssätze an sich) and intuitive propositions (Anschauungssätze an sich). An intuitive proposition contains at least one objective intuition, that is, a simple idea that represents exactly one object; a conceptual proposition contains no objective intuition. After Bolzano, philosophers dispensed with the distinction between conceptual and intuitive propositions. So why did Bolzano attach philosophical importance to it? I will argue that, ultimately, the value of (...) the distinction lies in the fact that conceptual and intuitive truths have different objective grounds: if a conceptual truth is grounded at all, its ground is a conceptual truth. The difference in grounds between conceptual and intuitive truths motivates Bolzano's criticism of Kant's view that intuition plays the fundamental role in mathematics, a conceptual science by Bolzano's lights. (shrink)

Le but de cet article est de présenter et d’évaluer la théorie de la fondation de Bernard Bolzano, c’est-à-dire sa théorie du concept exprimé et de la relation mise en jeu par « parce que ». Dans la première partie , le concept de fondation est distingué et mis en relation avec trois autres concepts : le concept de raison épistémique, le concept de causalité et le concept de déductibilité . Dans la seconde partie , je reconstruis la théorie bolzanienne (...) de la fondation sous forme axiomatique et j’en offre une discussion critique.The aim of the paper is to present and evaluate Bernard Bolzano’s theory of grounding, i.e. his theory of the concept expressed and the relation brought into play by ‘because’. In the first part the concept of grounding is distinguished from and related to three other concepts : the concept of an epistemic reason, the concept of causality and the concept of deducibility . In its second part Bolzano’s positive account of grounding is reconstructed in axiomatic form and critically discussed. (shrink)

In the course of the last few decades, Bolzano has emerged as an important player in accounts of the history of philosophy. This should be no surprise. Few authors stand at a more central junction in the development of modern thought. Bolzano's contributions to logic and the theory of knowledge alone straddle three of the most important philosophical traditions of the 19th and 20th centuries: the Kantian school, the early phenomenological movement and what has come to be known as analytical (...) philosophy. This paper identifies three Bolzanian theoretical innovations that warrant his inclusion in the analytical tradition: the commitment to ‘logical realism’, the adoption of a substitutional procedure for the purpose of defining logical properties and a new theory of a priori cognition that presents itself as an alternative to Kant's. All three innovations concur to deliver what counts as the most important development of logic and its philosophy between Aristotle and Frege. In the final part of the paper, I defend Bolzano against a common objection and explain that these theoretical innovations are also supported by views on syntax, which though marginal are both workable and philosophically interesting. (shrink)

For philosophers interested in ontological issues, the writings of the important figures of Austrian philosophy in the nineteenth and early twentieth century contain many buried treasures to rediscover. Bernard Bolzano, Franz Brentano, Alexius Meinong, and Edmund Husserl, to name just four grand names of that period, were highly aware of the importance of a feasible ontology for many of the philosophical questions they addressed throughout their works.

Content, according to Bolzano, is intransparent: our knowledge of certain essential features of the contents of our contentful mental acts is often severely limited. In this paper, I identify various intransparency theses Bolzano is committed to and present and evaluate the defence he offers for his view. I argue that while his intransparency theses may be correct, his defence is unsuccessful. Moreover, I argue that improving on his defence would require substantially modifying his general epistemology of content.