This paper defends a realist account of the composition of Newtonian forces, dubbed ‘residualism’. According to residualism, the resultant force acting on a body is identical to the component forces acting on it that do not prevent each other from bringing about its acceleration. Several reasons to favor residualism over alternative accounts of the composition of forces are advanced. (i) Residualism reconciles realism about component forces with realism about resultant forces while avoiding any threat of causal overdetermination. (ii) Residualism provides (...) a systematic semantics for the term ‘force’ within Newtonian mechanics. (iii) Residualism allows us to precisely apportion the causal responsibility of each component force in the ensuing acceleration. (iv) Residualism handles special cases such as null forces, single forces, and antagonistic forces in a natural way. (v) Residualism provides a neat picture of the causal powers of forces: each force essentially has two causal powers⎯the power to bring about accelerations (sometimes together with other co-directionnal forces) and the power to prevent other forces from doing so⎯exactly one of which is manifested at a time. (vi) Residualism avoids commitment to unobservable effects of forces: forces cause either stresses (tensile or compressive) or accelerations. (shrink)

Cantor’s theory of cardinal numbers offers a way to generalize arithmetic from finite sets to infinite sets using the notion of one-to-one association between two sets. As is well known, all countable infinite sets have the same ‘size’ in this account, namely that of the cardinality of the natural numbers. However, throughout the history of reflections on infinity another powerful intuition has played a major role: if a collectionAis properly included in a collectionBthen the ‘size’ ofAshould be less than the (...) ‘size’ ofB(part–whole principle). This second intuition was not developed mathematically in a satisfactory way until quite recently. In this article I begin by reviewing the contributions of some thinkers who argued in favor of the assignment of different sizes to infinite collections of natural numbers (Thabit ibn Qurra, Grosseteste, Maignan, Bolzano). Then, I review some recent mathematical developments that generalize the part–whole principle to infinite sets in a coherent fashion (Katz, Benci, Di Nasso, Forti). Finally, I show how these new developments are important for a proper evaluation of a number of positions in philosophy of mathematics which argue either for the inevitability of the Cantorian notion of infinite number (Gödel) or for the rational nature of the Cantorian generalization as opposed to that, based on the part–whole principle, envisaged by Bolzano (Kitcher). (shrink)

In Posterior Analytics 1.3, Aristotle advances three arguments against circular proof. The third argument relies on his discussion of circular proof in Prior Analytics 2.5. This is problematic because the two chapters seem to deal with two rather disparate conceptions of circular proof. In Posterior Analytics 1.3, Aristotle gives a purely propositional account of circular proof, whereas in Prior Analytics 2.5 he gives a more complex, syllogistic account. My aim is to show that these problems can be solved, and that (...) Aristotle’s third argument in 1.3 is successful. I argue that both chapters are concerned with the same conception of circular proof, namely the propositional one. Contrary to what is often thought, the syllogistic conception provides an adequate analysis of the internal deductive structure of the propositional one. Aristotle achieves this by employing a kind of multiple-conclusion logic. (shrink)

Logic is usually thought to concern itself only with features that sentences and arguments possess in virtue of their logical structures or forms. The logical form of a sentence or argument is determined by its syntactic or semantic structure and by the placement of certain expressions called “logical constants.”[1] Thus, for example, the sentences Every boy loves some girl. and Some boy loves every girl. are thought to differ in logical form, even though they share a common syntactic and semantic (...) structure, because they differ in the placement of the logical constants “every” and “some”. By contrast, the sentences Every girl loves some boy. and Every boy loves some girl. are thought to have the same logical form, because “girl” and “boy” are not logical constants. Thus, in order to settle questions about logical form, and ultimately about which arguments are logically valid and which sentences logically true, we must distinguish the “logical constants” of a language from its nonlogical expressions. (shrink)

Let me start with a well-known story. Kant held that logic and conceptual analysis alone cannot account for our knowledge of arithmetic: “however we might turn and twist our concepts, we could never, by the mere analysis of them, and without the aid of intuition, discover what is the sum [7+5]” (KrV, B16). Frege took himself to have shown that Kant was wrong about this. According to Frege’s logicist thesis, every arithmetical concept can be defined in purely logical terms, and (...) every theorem of arithmetic can be proved using only the basic laws of logic. Hence, Kant was wrong to think that our grasp of arithmetical concepts and our knowledge of arithmetical truth depend on an extralogical source—the pure intuition of time (Frege 1884, §89, §109). Arithmetic, properly understood, is just a part of logic. (shrink)

Philosophers after Leibniz used a technical idiom to classify and explain the nature of mental content. Substantive philosophical claims were formulated in terms of this vocabulary, including claims about the nature of mental representations, concepts, unconscious mental content, and consciousness. Despite its importance, the origin and development of this vocabulary is insufficiently well understood. More specifically, interpreters have failed to recognize the existence of two distinct and influential versions of the post-Leibnizian idiom. These competing formulations used the same technical terms (...) and taxonomic relations but assigned different connotations to those terms and employed different criteria for their application. This paper explains the two most influential versions of the post-Leibnizian idiom. (shrink)

This paper is aimed at understanding one central aspect of Bolzano's views on deductive knowledge: what it means for a proposition and for a term to be known a priori. I argue that, for Bolzano, a priori knowledge is knowledge by virtue of meaning and that Bolzano has substantial views about meaning and what it is to know the latter. In particular, Bolzano believes that meaning is determined by implicit definition, i.e. the fundamental propositions in a deductive system. I go (...) into some detail in presenting and discussing Bolzano's views on grounding, a priori knowledge and implicit definition. I explain why other aspects of Bolzano's theory and, in particular, his peculiar understanding of analyticity and the related notion of Ableitbarkeit might, as it has invariably in the past, mislead one to believe that Bolzano lacks a significant account oï a priori knowledge. Throughout the paper, I point out to the ways in which, in this respect, Bolzano's antagonistic relationship to Kant directly shaped his own views. (shrink)

Say that two sentences are ground-theoretically equivalent iff they are interchangeable salva veritate in grounding contexts. Notoriously, ground-theoretic equivalence is a hyperintensional matter: even logically equivalent sentences may fail to be interchangeable in grounding contexts. Still, there seem to be some substantive, general principles of ground-theoretic equivalence. For example, it seems plausible that any sentences of the form A∧B\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A \wedge B$$\end{document} and B∧A\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$B (...) \wedge A$$\end{document} are ground-theoretically equivalent. What, then, are in general the conditions for two sentences to stand in the relation of ground-theoretic equivalence, and what are the logical features of that relation? This paper develops and defends an answer to these questions based on the mode-ified truthmaker theory of content presented in my recent paper ‘Towards a theory of ground-theoretic content’ :785–814, 2018). (shrink)

This paper concerns Bertrand Russell’s changing views on negative judgement. ‘Negative judgement’ is considered in the context of three theories of judgement that Russell put forth at different times: a dual relation theory ; a multiple relation theory ; a psychological theory of judgement. Four issues are singled out for a more detailed discussion: quality dualism versus quality monism, that is, the question whether judgement comes in two kinds, acceptance and rejection, or whether there is only one judgement-quality ; the (...) structure of negative judging; the problem of truth-making for negative facts; the different roles of ‘fact’ in Russell’s theories of truth. What emerges from the discussion is a rough chronology of Russell’s views on negative judgement during the period from 1903 to 1948. (shrink)

The paper discusses Bernard Bolzano’s epistemological approach to believing and knowing with regard to the epistemic requirements of an axiomatic model of science. It relates Bolzano’s notions of believing, knowing and evaluation to notions of infallibility, immediacy and foundational truth. If axiomatic systems require their foundational truths to be infallibly known, this knowledge involves both evaluation of the infallibility of the asserted truth and evaluation of its being foundational. The twofold attempt to examine one’s assertions and to do so by (...) searching for the objective grounds of the truths asserted lies at the heart of Bolzano’s notion of knowledge. However, the explanatory task of searching for grounds requires methods that cannot warrant infallibility. Hence, its constitutive role in a conception of knowledge seems to imply the fallibility of such knowledge. I argue that the explanatory task contained in Bolzanian knowing involves a high degree of epistemic virtues, and that it is only through some salient virtue that the credit of infallibility can distinguish Bolzanian knowing from a high degree of Bolzanian believing. (shrink)

A response to critics, Douglas Patterson and Mark Textor, on Künne's modest theory of truth in *Conceptions of Truth*.

Lecture notes from Husserl's logic lectures published during the last 20 years offer a much better insight into his doctrine of the forms of meaning than does the fourth Logical Investigation or any other work published during Husserl's lifetime. This paper provides a detailed reconstruction, based on all the sources now available, of Husserl's system of logical grammar. After having explained the notion of meaning that Husserl assumes in his later logic lectures as well as the notion of form of (...) meaning as it features in ‘doctrine of the forms of meaning’, I present a system of rules that describes all the various forms of meaning that Husserl singles out in his lectures. (shrink)

This paper explores a novel notion of self-explanation that combines ideas from two sources: the tripartite account of explanation, according to which a proposition can help explain another either in the capacity of a reason why the latter obtains or in the capacity of an explanatory link, and the notion of an empty-base explanation, which generalizes the ideas of explanation by zero-grounding and explanation by status. After having introduced these ideas and the novel notion of self-explanation, I argue that the (...) latter has the potential to resist extant arguments against the possibility of self-explanation. In the remainder of the paper, I discuss candidates for such self-explanatory propositions and suggest possible applications for Humeanism about laws of nature, the debate on the grounds of ground, the rationalist tradition, and philosophical theology. (shrink)

Prolegomena to Pure Logic (1900) is the definitive statement of Husserl’s early logic. But what does it say that logic is? I argue that Husserl in the Prolegomena thinks logic is its own discipline, namely the “doctrine of science” (Wissenschaftslehre), but has two conflicting ideas of what that is. One idea—expressed by the book’s general argument, and which I call Husserl’s Austrian Semanticism about logic—is that the Wissenschaftslehre is the positive science explaining what science is (which turns out just to (...) be the study of meaning) plus the dependent art that, applying the science, teaches us how to scientifically know. The other idea—expressed by the book’s opening chapter, and which I call Husserl’s German Idealism about logic—is that the Wissenschaftslehre is the purely reflective self-knowing of science, independent of science’s positive expansion. These two ideas are incompatible. Thus, the Prolegomena is ambivalent on what logic is. But since the ambivalence only deepens the significance of Husserl’s early logic, the ambivalence should be embraced. (shrink)

Logical semantics includes once again structured meanings in its repertoire. The leading idea is that semantic and syntactic structure are more or less isomorphic. A key motive for reintroducing sensitivity to semantic structure is to obtain fine‐grained meanings, which are individuated more finely than in possible‐world semantics, namely up to necessary equivalence. Just getting the truth‐conditions right is deemed insufficient for a full semantic analysis of sentences. This paper surveys some of the most recent contributions to the program of structured (...) meaning, while providing historical background. I suggest that to make substantial advances the program needs to solve the problem of propositional unity and develop an intensional mereology of abstract objects. (shrink)

In this article from 1928, translated here for the first time, Tanabe Hajime examines the concept of self-evidence, mainly in the light of Husserl and Brentano. The author starts out by establishing, through a preliminary analysis of the Cartesian cogito, two criteria for self-evidence, namely adequate fulfillment of the intention of Sosein, and the coextension of Dasein and Sosein (being-there, or existence, and being-such, or essence/properties). He then proceeds to consider four domains of knowledge through the prism of the question (...) of their claim to self-evidence: knowledge of mathematical objects, categorial intuition, the ontological proof for the existence of God and finally, outer perception. Dedicating the last paragraph to a critical assessment of Husserl’s account of perception, the author concludes that all self-evidence is founded on inner perception. Outlining a creative appropriation of phenomenology while elucidating the conditions for certainty, this text constitutes an important milestone in a period leading up to Tanabe’s break with Nishida as well as to his critique of Heidegger, thus laying the groundwork for his independent philosophical stance. (shrink)

It is widely recognized that Frege's systematic conception of science has a major impact on his work. I argue that central to this conception and its impact is Frege's Simplicity Requirement that a scientific system must have as few primitive truths as possible. Frege states this requirement often, justifies it in several ways, and appeals to it to motivate important aspects of his broader views. Acknowledging its central role illuminates several aspects of his work in new ways, including his treatment (...) of truth values, logical concepts, and the dependence relations that induce a ‘natural order’ of truths. (shrink)

Philosophers of mathematics commonly distinguish between explanatory and non-explanatory proofs. An important subclass of mathematical proofs are proofs by induction. Are they explanatory? This paper addresses the question, based on general principles about explanation. First, a recent argument for a negative answer is discussed and rebutted. Second, a case is made for a qualified positive take on the issue.

The view that mathematics deals with ideal objects to which we have epistemic access by a kind of perception has troubled many thinkers. Using ideas from Husserl’s phenomenology, I will take a different look at these matters. The upshot of this approach is that there are non-material objects and that they can be recognized in a process very closely related to sense perception. In fact, the perception of physical objects may be regarded as a special case of this more universal (...) way of recognizing objects of any kind. (shrink)

Frege’s account, according to which the problem of how thoughts are apprehended should be a part of psychology, has led scholars to the idea that every consideration regarding subjectivity is absent in this author. From the latter follows a certain way of conceiving the relation between Frege and Husserl which establishes an absolute chasm between both authors regarding the topic mentioned. In the present contribution an extremely different view is defended, namely, that Frege plays an intermediate role between 19th century (...) Platonism and husserlian phenomenology. The main focus of the argument is the commitment between naturalism and idealism which characterizes Platonism before Frege and the beginning of its overcoming carried out by him. (shrink)

In this paper I discuss Künne’s Modest Theory of truth, and develop a variation on a worry that Field expresses with respect to Horwich’s related view. The worry is not that deflationary accounts are false, but rather that, because they take propositions as truth-bearers, they are not philosophically interesting. Compatibly with the intuitions of ordinary speakers, we can understand proposition so that the proposals do account for a property that such truth-bearers have. Nevertheless, we saliently apply the truth-concept also to (...) entities such as utterances or assertions , and the de flationary accounts do not provide a similarly deflationary account for those applications. In fact, there are good reasons to suspect that no such account would be forthcoming; we need something more substantive or in flationary there. (shrink)

In this article, I shed some light on Meinong’s motivations for the theory of objects. I argue that one of its basic principles, the principle of indifference, is driven by an intuition common to many Austrian philosophers, which is that something must first be somehow pre-given in order to simply address the issue of its being or non-being. Meinong’s way of spelling out this intuition, I suggest, is to show that there are homeless objects, that is, objects that are not (...) dealt with by any of the existing sciences. Therefore, the indispensability of the theory of objects lies in the plausibility of the thesis that there are such homeless objects. I analyse and evaluate two Meinongian arguments supporting this thesis, I explain how Meinong came to believe that they support the indispensability of the theory of objects, and I stress some advantages of this account over Brentano’s intentionality thesis. (shrink)

Attempts to articulate the real meaning or ultimate significance of a famous theorem comprise a major vein of philosophical writing about mathematics. The subfield of mathematical logic has supplie...

This presentation aims to clarify the historical and theoretical background of the studies included in this issue of Philosophiques, which focus on the work of Husserl during the period of Halle . After a brief description of Husserl’s early years of apprenticeship in philosophy between 1876 and his studies with Brentano in Vienna, I identify several steps that marked the development of his philosophy from his arrival in Halle to the publication of the Logical Investigations : his studies under the (...) direction of C. Stumpf, the publication of the first volume of Philosophy of Arithmetic, the researches belonging to the project of the second volume of this work, the abandonment of this project and the development of the phenomenology of the Logical Investigations. The last part of this paper is an examination of the philosophical issues underlying the disputatio on D. W. Smith’s recent book on Husserl’s philosophy. (shrink)

This paper deals with two issues. First, it identifies structured propositions with logical procedures. Second, it considers various rigorous definitions of the granularity of procedures, hence also of structured propositions, and comes out in favour of one of them. As for the first point, structured propositions are explicated as algorithmically structured procedures. I show that these procedures are structured wholes that are assigned to expressions as their meanings, and their constituents are sub-procedures occurring in executed mode. Moreover, procedures are not (...) mere aggregates of their parts; rather, procedural constituents mutually interact. As for the second point, there is no universal criterion of the structural isomorphism of meanings, hence of co-hyperintensionality, hence of synonymy for every kind of language. The positive result I present is an ordered set of rigorously defined criteria of fine-grained individuation in terms of the structure of procedures. Hence procedural semantics provides a solution to the problem of the granularity of co-hyperintensionality. (shrink)

RÉSUMÉ: Dans cet article, j’entreprends de clarifier le projet (frégéen) d’une logique de l’arithmétique -- tel qu’il a été discuté par Natorp et Rickert -- en distinguant trois questions directrices. Le nombre est-il un objet logique? L’arithmétique est-elle réductible à la logique? Est-il possible de déduire les opérations arithmétiques de lois purement logiques? Ma thèse est que la distinction rigoureuse de ces trois questions permet de lever une grande partie des obscurités qui affectent en généralle programme d’une logique de l’arithmétique. (...) La contribution néo-kantienne à ce programme se trouve du même coup éclairée d’une lumière nouvelle.ABSTRACT: In this article, I try to shed light on the (Fregean) project of a logic of arithmelic-as discussed by Natorp and Rickert-by outlining three main questions. Is the number a logical object? Is arithmetic reducible to logic? Is it possible to deduce the arithmetical operations from purely logical laws? I argue that rigorous distinction between these three questions makes it possible to elucidate many problems affecting the program of a logic of arithmetic. The Neo-Kantian contribution to this program is at the same time considered in a new light. (shrink)

Throughout more than two millennia philosophers adhered massively to ideal standards of scientific rationality going back ultimately to Aristotle’s Analytica posteriora . These standards got progressively shaped by and adapted to new scientific needs and tendencies. Nevertheless, a core of conditions capturing the fundamentals of what a proper science should look like remained remarkably constant all along. Call this cluster of conditions the Classical Model of Science . In this paper we will do two things. First of all, we will (...) propose a general and systematized account of the Classical Model of Science. Secondly, we will offer an analysis of the philosophical significance of this model at different historical junctures by giving an overview of the connections it has had with a number of important topics. The latter include the analytic-synthetic distinction, the axiomatic method, the hierarchical order of sciences and the status of logic as a science. Our claim is that particularly fruitful insights are gained by seeing themes such as these against the background of the Classical Model of Science. In an appendix we deal with the historiographical background of this model by considering the systematizations of Aristotle’s theory of science offered by Heinrich Scholz, and in his footsteps by Evert W. Beth. (shrink)

This paper concentrates on some aspects of the history of the analytic-synthetic distinction from Kant to Bolzano and Frege. This history evinces considerable continuity but also some important discontinuities. The analytic-synthetic distinction has to be seen in the first place in relation to a science, i.e. an ordered system of cognition. Looking especially to the place and role of logic it will be argued that Kant, Bolzano and Frege each developed the analytic-synthetic distinction within the same conception of scientific rationality, (...) that is, within the Classical Model of Science: scientific knowledge as cognitio ex principiis . But as we will see, the way the distinction between analytic and synthetic judgments or propositions functions within this model turns out to differ considerably between them. (shrink)

In this paper I investigate the idea that in conceptual analysis we are in a substantial way concerned with revealing metaphysical grounds. I argue that a recent proposal fails, according to which we aim to reveal what complex concepts are grounded in. The notion ofcomposition, rather than that ofgrounding, is the best way to understand the intuitive hierarchy of concepts. In an analysis we reveal thecomponentsorpartsof complex concepts and their structure. Finally, I propose an alternative role for grounding in our (...) accounts of analysis: in analyses we reveal truths about the composition of concepts that serve as grounds for truths about theirfunctions, which are what we want to understand. (shrink)

In this paper I investigate the idea that in conceptual analysis we are in a substantial way concerned with revealing metaphysical grounds. I argue that a recent proposal fails, according to which we aim to reveal what complex concepts are grounded in. The notion ofcomposition, rather than that ofgrounding, is the best way to understand the intuitive hierarchy of concepts. In an analysis we reveal thecomponentsorpartsof complex concepts and their structure. Finally, I propose an alternative role for grounding in our (...) accounts of analysis: in analyses we reveal truths about the composition of concepts that serve as grounds for truths about theirfunctions, which are what we want to understand. (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)

In his booklet "Contributions to a better founded presentation of mathematics" of 1810 Bernard Bolzano made his first serious attempt to explain the notion of a rigorous proof. Although the system of logic he employed at that stage is in various respects far below the level of the achievements in his later Wissenschaftslehre, there is a striking continuity between his earlier and later work as regards the methodological constraints on rigorous proofs. This paper tries to give a perspicuous and critical (...) account of the fragmentary logic of Beyträge, and it shows that there is a tension between that logic and Bolzano's methodological ban on ?kind crossing? (shrink)

This explorative article is organized around a set of questions concerning the concept of a function. First, a summary of certain general facts about functions that are a common coin in contemporary logic is given. Then Frege's attempt at clarifying the nature of functions in his famous paper Function and Concept and in his Grundgesetze is discussed along with some questions which Freges' approach gave rise to in the literature. Finally, some characteristic uses of functional notions to be found in (...) the work of Bernard Bolzano and in Edmund Husserl's early work are presented and elucidated. (shrink)

This paper analyzes and evaluates Bolzano's remarks on the apagogic method of proof with reference to his juvenile booklet "Contributions to a better founded presentation of mathematics" of 1810 and to his ?Theory of science? (1837). I shall try to defend the following contentions: (1) Bolzanos vain attempt to transform all indirect proofs into direct proofs becomes comprehensible as soon as one recognizes the following facts: (1.1) his attitude towards indirect proofs with an affirmative conclusion differs from his stance to (...) indirect proofs with a negative conclusion; (1.2) by Bolzano's lights arguments via consequentia mirabilis only seem to be indirect. (2) Bolzano does not deny that indirect proofs can be perfect certifications (Gewissmachungen) of their conclusion; what he denies is rather that they can provide grounds for their conclusions. (2.1) They cannot do the latter, since they start from false premises and (2.2) since they make an unnecessary detour. (3) The far-reaching agreement between his early and late assessment of apagogical proofs (in the Beyträge of 1810 and the Wissenschaftslehre of 1837) is partly due to the fact that he develops his own position always against the background of Wolff's and Lambert's views. (shrink)

This article introduces the first English translation of one of Tanabe’s early essays on metaphysics. It questions the relation of the universal to the particular in context of logic, phenomenology, Neo-Kantian epistemology, and classical metaphysics. Tanabe provides his reflections on the nature of the concept of universality and its constitutive relation to phenomenal particulars through critical analyses of the issue as it is discussed across various schools of philosophy including: British Empiricism, the Marburg School, the Austrian School, the Kyoto School, (...) and Platonism. In this essay, Tanabe reveals his ability to think metaphysically the ground for the possibility of reasoning and dares to voice his own thought beyond references to the most prominent thinkers of his time from distinct intellectual traditions in both the east and the west. This essay, therefore, demonstrates that his strong tendency to move beyond the received epistemology and phenomenology of the European intellectual tradition to metaphysics was already present in the early days of his academic life and thereby marks a more general contribution of the Kyoto School of Philosophy to distinct European schools of thought in the early twentieth century. (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)

Twardowski'sOn the Content and Object of Presentations(1894) is one of the most influential works that Austrian philosophy has left to posterity. The manuscriptLogik(1894–1895) supplements that work and allows us to reconstruct Twardowski's theory of judgement. These texts raise several issues, in particular whether Twardowski accepts propositions and states of affairs in his theory of judgement and whether his theory is acceptable. This article presents Twardowski's theory, shows that he accepts states of affairs, that he has a notion of proposition, and (...) that his theory is interesting and sophisticated. (shrink)

Bernard Bolzano (1781–1848) is commonly thought to have attempted to develop a theory of size for infinite collections that follows the so-called part–whole principle, according to which the whole is always greater than any of its proper parts. In this paper, we develop a novel interpretation of Bolzano’s mature theory of the infinite and show that, contrary to mainstream interpretations, it is best understood as a theory of infinite sums. Our formal results show that Bolzano’s infinite sums can be equipped (...) with the rich and original structure of a non-commutative ordered ring, and that Bolzano’s views on the mathematical infinite are, after all, consistent. (shrink)

This volume will be of particular interest to researchers working in the history, and in the philosophy, of logic and mathematics, and more generally, to ...

Logicism is the view that mathematical truths are logical truths. But a logical truth is commonly thought to be one with a universally valid form. The form of “7 > 5” would appear to be the same as “4 > 6”. Yet one is a mathematical truth, and the other not a truth at all. To preserve logicism, we must maintain that the two either are different subforms of the same generic form, or that their forms are not at all (...) what they appear. The historical record shows that Russell pursued both these options, but that the struggle with the logical paradoxes pushed him away from the first kind of response and toward the second. An object cannot itself have a kind of inner logical complexity that makes a proposition have a different logical form merely in virtue of being about it, nor can their representatives in logical forms be single things different for different forms, at least not without postulating too many such objects and thereby creating Cantorian diagonal paradoxes. There are only apparent objects which are actually fragments of logical forms, different in different cases. (shrink)