Gottlob Frege

The main question of this article is that what are the important differences or similarities between Aristotle's and Frege's analysis of the categorical proposition? Based on the famous view, Aristotle analyzes the categorical proposition into three components: Subject, Predicate and Relation; while Frege analyzes the categorical proposition into two components of Variable and Function, and therefore; these two analyses are completely different and there is no similarity between them. In the other article, I have argued that in the Aristotle's viewpoint, (...) in the logical analysis of the categorical proposition, against its linguistic analysis, it is divided into two main components of subject and predicate. At this article, I have shown that by accepting of this analysis and based on it, it becomes clear that: firstly, there are important similarities between these two analyses: 1) both are two-part analyses 2) Aristotle, like Frege, considers «to be attributed to something else» to be the essential feature of the predicate part; Secondly, there are important differences between them: 1) Aristotle considers «to be attributed to something else» to be merely the essential property of the Role of Predicate, but Frege considers it to be also the essential property of general concepts that replaces in this role, and therefore 2) Frege, against Aristotle, maintains that general concepts cannot be the subject of propositions. This viewpoint of Frege is based on the «Fundamental distinction between Object and Concept». Therefore the root of the differences between the two analyses should be sought in this assertion.. (shrink)

Gottlob Frege (1848-1925) has been called ‘the undisputed father of analytic philosophy’ and ‘the most important logician since Aristotle.’ Even if his impact on philosophy were to extend no further than his decisive influence on leading early twentieth-century thinkers of the stature of Bertrand Russell, Ludwig Wittgenstein and Rudolf Carnap, that alone would assure him a notable place in the history of modern philosophy. Nevertheless, there are other areas of Frege’s intellectual activity that have largely escaped the attention of his (...) commentators. One of these is his seldom-noticed attempt late in life to write about political theology. In this reconstruction of Frege’s view, based on a context-sensitive close reading of his fragmentary writing on theology, I document Frege’s commitment to a highly politicized conception of theology’s public role. This conception is infused with the ideology of Germany’s Far-Right völkisch (pan-German ethnic-nationalist) movement and steeped in the political strife of early Weimar-era Germany. Frege’s interest in theology was evidently rooted not so much in conventionally spiritual concerns as in the decidedly innerweltlich desire to help turn the tide in German politics in favor of the ultranationalist Far Right. His theology was, accordingly, a political theology of völkisch, antisemitic, and anti-socialist nationalism. (shrink)

Frege is an anti-psychologist about logic who takes logic to be sharply distinguished from psychology. However, Frege also takes judgment, which seems to be a subject of psychology, to be essential to logic. Van der Schaar attempts to explain away this tension by arguing that judgments relevant to logic in Frege are not mental actions psychology deals with. Against this reading, I show that for Frege, judgments are mental actions consistently. The tension in question should be explained away by clarifying (...) the sense in which judgment is essential to logic for Frege. He takes judgment to be essential to logic because he thinks that logic requires judgments to be performed. Logic requires logicians to be committed to truth, and it is by judgments that we are committed to truth. If Frege takes judgment to be essential to logic only in this sense, he is not thereby committed to logical psychologism. (shrink)

This dissertation is about the structure of thought. Following Gottlob Frege, I define a thought as the sort of content relevant to determining whether an assertion is true or false. The historical component of the dissertation involves interpreting Frege’s actual views on the structure of thought. I argue that Frege did not think that a thought has a unique decomposition into its component senses, but rather the same thought can be decomposed into senses in a variety of distinct ways. I (...) extend Frege’s position and use it to develop an account of the hierarchy of senses, the senses expressed by indexicals and demonstratives, and the distinction between logical and non-logical structure. I also discuss various connections with the nature of meta-representation, our capacity for reflective judgment, some aspects of the structure of conscious experience, the way we perceive regions of space and durations of time, and our conscious awareness of our own perceptions and events of thinking. (shrink)

Blackburn has outlined a formal account for moral expressivism, and we argued that the moral Frege-Geach problem can be solved formally by appending two rules for the boo-operator which are missing from his account. We then extended Blackburn’s formal account to generate a similar solution to the problem in modal context and showed that the validity of the modal argument can be preserved too in modal expressivism. However, the higher-order element endorsed by Blackburn does not seem necessary for solving the (...) Frege-Geach problem. Nor is his extension from moral expressivism to modal expressivism tenable, since the latter violates its own ontological constraint. A general moral is drawn on the basis on three observations made in evaluating Blackburn’s expressivism. (shrink)

In the paper, I propose a novel approach to Frege’s view on the principle of compositionality, its relation to the propositional holism and the formation of concepts. The main idea is to distinguish three stages of constructing a logically perfect language. At the first stage, only a sentence as a whole expresses a Thought. It is impossible to assign meaning to less complex units. This is the stage of an ordinary language. The second phase concerns the proper level of construction (...) of a logically perfect language. We are forced to discriminate syntactic and semantic parts of sentences to account for the inference relations. We can distinguish senses and references of parts of sentences. Furthermore, it is possible here to choose between different ways of analysing the given Thought. Finally, at the third stage, every expression of the language has an unambiguous sense and this sense determines a unique reference. The logically perfect language is ready. We may view Thoughts as composed from primitive elements. Moreover, the senses of parts of a sentence correspond to the parts of a Thought, so that the structure of the sentence serves as the image of the structure of the Thought. The principle of compositionality is met and we can discern how understanding of the infinite numbers of Thoughts is possible and how languages are learnable. The main advantage of the presented view is that it allows accommodating some aspects of Frege’s philosophy that are often seen as mutually incompatible. Furthermore, I submit extensive textual data in favour of the discussed views and conceptions. (shrink)

Wittgenstein seeks to throw light on our concept of understanding by looking at how misunderstandings arise and what kinds of failure they involve. He discerns a peculiar sort of misunderstanding in the writings of the social anthropologist James Frazer. In Frazer’s hands, the anthropological project of enabling us to understand human behavior seems to yield the result that there are certain forms of human behavior that simply cannot be understood. The source of Frazer’s misunderstanding, according to Wittgenstein, is that he (...) places narrow requirements on what could count as meaningful, prior to and independently of his encounter with the subjects of his interpretation. Frazer, like some of the philosophers Wittgenstein addresses in his other works, succumbs to nonsense in his very attempt to draw the limits of sense. My aim in this chapter is to clarify the connections between Wittgenstein’s criticism of Frazer and his criticism of his fellow philosophers, in particular of Frege. The materials I draw on stem from various periods in Wittgenstein’s career, and they reveal, in my mind, an important continuity in Wittgenstein’s thought: addressing misunderstanding, in Wittgenstein’s view, is fundamentally an ethical problem, not a theoretical one. (shrink)

Frege's Grundgesetze der Arithmetik offers a conception of cpLogic as the study of functions. Among functions are included those that are concepts, i.e. characteristic functions whose values are the logical objects that are the True/the False. What, in Frege's view, are the objects the True/the False? Frege's stroke functions are themselves concepts. His stipulation introducing his negation stroke mentions that it yields [...]. But curiously no accommodating axiom is given, and there is no such theorem. Why is it that some (...) of Frege's informal stipulations never made appearances as axioms? I offer an explanation that sheds new light on the Grundgesetze. No axioms should over-determination the True as a logical object. Perhaps the True = 0, as would be common in the mathematics of characteristic functions. But the logical objects that are cardinal numbers are value ranges correlated with second-level numerical concepts by a non-homogeneous second-level value-range function [...]. The existence of concepts would be ontologically circular if the True is itself a number. We find this circularity perfectly agreeable to Frege, and suggest that he had accepted that the existence of functions that are concepts in his cpLogic may well be ontologically inseparable from the existence of his value-range function. His cpLogic itself stands or falls with the viability of some value-range function. (shrink)

Neo-Fregean logicists claim that Hume's Principle (HP) may be taken as an implicit definition of cardinal number, true simply by fiat. A longstanding problem for neo-Fregean logicism is that HP is not deductively conservative over pure axiomatic second-order logic. This seems to preclude HP from being true by fiat. In this paper, we study Richard Kimberly Heck's Two-sorted Frege Arithmetic (2FA), a variation on HP which has been thought to be deductively conservative over second-order logic. We show that it isn't. (...) In fact, 2FA is not conservative over $n$-th order logic, for all $n \geq 2$. It follows that in the usual one-sorted setting, HP is not deductively Field-conservative over second- or higher-order logic. (shrink)

This paper continues my discussion with Michael Dummett on Frege’s senses, published in The Philosophy of Michael Dummett and further developed in Diametros. In his reply to my original paper, Dummett came to agree with me that senses are neither objects nor functions, since they have a categorially different kind of linguistico-metaphysical function to perform. He then asks how we might quantify over senses, if they are neither objects nor functions. He discusses two main options, and finds one unviable and (...) the other “very un-Fregean.” I then offer a Fregean or neo-Fregean option in my rejoinder. And I still hold that this way out will do the job, or is at least plausible enough that the burden of persuasion is on those who disagree. But I hope to show in this paper that on a more complete examination of Frege, there are at least twenty Fregean or neo-Fregean ways out, with the one I proposed being option. (shrink)

Theoria, Volume 88, Issue 2, Page 464-479, April 2022.

Frege argues that number is so unlike the things we accept as properties of external objects that it cannot be such a property. In particular, number is arbitrary in a way that qualities are not, and number is not predicated of its subjects in the way that qualities are. Most Aristotle scholars suppose either that Frege has refuted Aristotle's number theory or that Aristotle avoids Frege's objections by not making numbers properties of external objects. This has led some to conclude (...) that Aristotle's accounts of arithmetical and geometrical objects differ substantially. I close this supposed gap by showing that Aristotle's arithmetical objects, like geometrical objects, are just certain sensible things qua certain properties they in fact possess. Specifically, numbers are pluralities qua quantitative or relational properties like ten units or ten. I show that this view is resistant to the Fregean concerns about arbitrariness and numerical predication. (shrink)

Theoria, Volume 88, Issue 2, Page 464-479, April 2022.

In contemporary historical studies Peano is usually linked to the logical tradition pioneered by Frege. In this paper I question this association. Specifically, I claim that Frege and Peano developed significantly different conceptions of a logical calculus. First, I clam that while Frege put the systematisation of the notion of inference at the forefront of his construction of an axiomatic logical system, Peano modelled his early logical systems as mathematical calculi and did not really attempt to justify reasoning. Second, I (...) argue that in later works on logic Peano advanced towards a deductive approach that was closer to Frege’s standpoint. (shrink)

By means of a reductio argument, Wittgenstein’s Tractatus calls into question the very idea that we can represent logical form. My paper addresses three interrelated questions: first, what conception of logical form is at issue in this argument? Second, whose conception of logic is this argument intended to undermine? And third, what could count as an adequate response to it? I show that the argument construes logical form as the universal, underlying correlation of any representation and the reality it represents. (...) I further show that the argument seeks to undermine core commitments of Frege’s and Russell’s. But the reductio, as I read it, is not intended to establish the falsity of any of their specific assumptions. Rather, its aim is to make manifest the indeterminacies that underlie the language in which these assumptions are framed, and establish the need for a transformation of that language. So understood, Wittgenstein’s argument exemplifies his idea that philosophy is not a theory, but an activity of elucidation. The interpretation I propose bears on one of the central debates in the literature, namely how we should understand Wittgenstein’s contention that his elucidations succeed despite being nonsensical. (shrink)

In [Boccuni 2010], a predicative fragment of Frege’s blv augmented with Boolos’ unrestricted plural quantification is shown to interpret pa2. The main disadvantage of that axiomatisation is that it does not recover Frege Arithmetic fa because of the restrictions imposed on the axioms. The aim of the present article is to show how [Boccuni 2010] can be consistently extended so as to interpret fa and consequently pa2 in a way that parallels Frege’s. In that way, the presented system will be (...) compared with the system pe in [Ferreira 2018] and some relevant differences between the two will be highlighted. (shrink)

A lot of philosophy taught to science students consists of scientific methodology. But many philosophy of science textbooks have a fraught relationship with methodology, presenting it either a system of universal principles or entirely permeated by contingent factors not subject to normative assessment. In this paper, I argue for an alternative, heuristic perspective for teaching methodology: as fallible, purpose- and context-dependent, subject to cost-effectiveness considerations and systematically biased, but nevertheless subject to normative assessment. My pedagogical conclusion from this perspective is (...) that philosophers should aim to teach science students heuristic reasoning: strategies of normative method choice appraisal that are sensitive to purposes, contexts, biases and cost-effectiveness considerations; and that we should do so by teaching them exemplars of such reasoning. I illustrate this proposal at the hand of three such exemplars, showing how they help students to appreciate the heuristic nature of both methods and methodology, and to normatively assess method choice in such circumstances. (shrink)

European Journal of Philosophy, Volume 29, Issue 4, Page 988-1009, December 2021.

Onofri [Onofri, A. 2018. ‘The Publicity of Thought.’ Philosophical Quarterly 68 (272): 521–541.] proposes an individuation criterion for thoughts that purports to satisfy both shareability (the notion that different thinkers, or a single thinker at different times, can and generally do think type-identical thoughts) and Frege's constraint (according to which two thoughts are different if it is possible for a rational subject to endorse one while rejecting the other). I argue that his proposal fails to satisfy Frege's constraint. Then I (...) propose a modification to Onofri's proposal to fix the problem. (shrink)

Danielle Macbeth's purpose in Macbeth 2005 is threefold. Her monograph proposes "to provide a logical justification for all aspects of Frege's peculiar notation, to motivate and explain the developments in Frege's views over the course of his intellectual life, and to explicate his most developed, critically reflective conception of his Begriffschrift, his formula language of pure thought". I shall focus here on a few selected aspects of the first and third points and leave on the side the discussion of the (...) historical development of Frege's views on logic, semantics and mathematics. The book's underlying claim is that although Frege's logical language, "can of course be read as a language of quantificational logic, [it] can also be read very differently", so much so, as a matter of fact, that although Frege's logic is usually thought of as a "notational variant of standard quantificational logic", it is nevertheless "unknown to us". This naturally prompts three questions : "What is Frege's logic?", "What is quantificational logic?", and given the way we understand formal languages for first and higher order predicate logic, most notably the notions of argument 2 place, of scope and of binding : "How come Frege's logic says nothing about such notions, or something so different from what we say?". (shrink)

En el apartado Freges Versuch, incluido en Filosofía de la aritmética, Husserl abiertamente señala que en los Fundamentos de la aritmética de G. Frege no existe un análisis lógico adecuado del concepto de número en términos de equinumerosidad. Según Husserl, la caracterización de Frege del concepto de número cardinal, en estrecha conexión con la noción de correspondencia uno- a-uno, es errónea. El objetivo principal de este artículo es mostrar que esta interpretación de Husserl sobre la obra de Frege, específicamente en (...) este apartado, contiene una serie de errores y confusiones graves. Palabras clave: Husserl, Frege, psicologismo, Filosofía de la aritmética, equinumerosidad, fenomenología, correspondencia uno-a-uno. (shrink)

Resumen En esta discusión expongo algunas objeciones a las siguientes tesis de Velázquez 2020: 1) que tanto Descartes como Frege sostienen que las entidades aritméticas son irreductibles a procesos empíricos; 2) que, en el caso de Descartes, dichas entidades son “perennes, inherentes a la propia constitución y funcionamiento de la mente” y 3) que Frege impugnó la filosofía matemática de Mill por psicologista. Sostengo que la segunda tesis no es, per se, controversial, pero que sí lo es en el contexto (...) del artículo de Velázquez.In this discussion I present objections to the following theses in Velázquez 2020: 1) that both Descartes and Frege maintain that arithmetic entities are irreducible to empirical processes; 2) that, in the case of Descartes, these entities are “perennial, inherent to the very constitution and functioning of the mind”, and 3) that Frege contested Mill’s mathematical philosophy for being psychologistic. I argue that the second thesis is not, per se, controversial, but that it is controversial in the context of Velázquez’s article. (shrink)

I take issue with Glezakos’s explanation of why Frege’s puzzle is un-puzzling. On her view, Frege’s statement – how can sentences of the form a=a and a=b, if true, differ in cognitive value if they express the same semantic content/are made true by the same object’s self-identity? – should not be considered any puzzling either because it is on the whole circular, or because, neutrally stated, it cannot even be set up. I argue against this that if, as she takes (...) it, Frege’s statement is “problematic” it is not for the reasons she gives, but because it rests upon a couple of questionable assumptions: i) there is no ambiguity as to which aspect of the sign (in its relation to the referent) is relevant to a neutral statement of the puzzle ii) it is of the (sentence) forms themselves one may sensibly say they differ in cognitive value. (shrink)

Logical Investigations (notably, The Thought) is one of the works wherein Frege voices his hostility to psychologism in logic, science, and semantics. Such hostility lies, arguably, behind his threefold conceptual distinction between thought (Gedanke), thinking (Denken), and ideas (Vorstellungen). In this essay I investigate, to begin with, Frege’s motivations for drawing the distinction and keeping thinking episodes (one of the meanings of ‘thoughts’ in English) out of the picture. It turns out, or so I argue, that psychologism threatens, on Frege’s (...) view, to destroy the objectivity requirement by which thoughts are defined as answerable contents. I then draw a connection between this feature in Frege’s view and an on-going debate in philosophy of mind and language over the nature of world-directed thoughts and show that the feature lies at the heart of the singularist stance. Finally, I show that, despite Frege’s own hostility to all that bears the mark of the subjective in logic, science, and semantics, a psychological argument can be mounted in support of singularism (i.e. the view that some of our thoughts are about particulars qua particulars) using his disparaged notion of idea (Vorstellung) and that, appearances notwithstanding, the argument is compatible with the objectivity requirement on answerable thought-contents. (shrink)

My aim in this paper is to show in what sense one might characterize ‘analytic philosophy’. In its first part I present some meta-philosophical ideas about the topic and in its following and more substantial parts I develop, as an example of what is being said, one and only one philosophical problem in the Philosophy of Language. The philosophical problem I consider, the so called ‘identity problem’ or ‘Frege Puzzle’ was first advanced by Frege and was treated and developed by (...) several philosophers during the 20th Century. I consider some of the main solutions for the puzzle trying to show by philosophical considerations what I had previously said by meta-philosophical ideas about analytic philosophy. (shrink)

We note that a plural version of logicism about arithmetic is suggested by the standard reading of Hume's Principle in terms of `the number of Fs/Gs'. We lay out the resources needed to prove a version of Frege's principle in plural, rather than second-order, logic. We sketch a proof of the theorem and comment philosophically on the result, which sits well with a metaphysics of natural numbers as plural properties.

نگاهی بر استدلال‌های دونالد دیویدسون در باب ضرورت زبان برای اندیشه .

Due programmi diversi si intersecano nel lavoro di Frege sui fondamenti dell’aritmetica: • Logicismo: l’aritmetica `e riducibile alla logica; • Estensionalismo: l’aritmetica `e riducibile a una teoria delle estensioni. Sia nei Fondamenti che nei Principi, Frege articola l’idea che l’aritmetica sia riducibile a una teoria logica delle estensioni.

Call a family F of subsets of a set E inductive if ∅ ∈ F and F is closed under unions with disjoint singletons, that is, if ∀X∈F ∀x∈E–X(X ∪ {x} ∈ F]. A Frege structure is a pair (E.

: Frege's philosophical writings, including the "logistic project," acquire a new insight by being confronted with Kant's criticism and Wittgenstein's logical and grammatical investigations. Between these two points a non-formalist history of logic is just taking shape, a history emphasizing the Greek and Kantian inheritance and its aftermath. It allows us to understand the radical change in rationality introduced by Gottlob Frege's syntax. This syntax put an end to Greek categorization and opened the way to the multiplicity of expressions producing (...) their own intelligibility. This article is based on more technical analyses of Frege which Claude Imbert has previously offered in other writings (see references). (shrink)

Unless you are a Frege scholar, or a philosopher of mathematics, if you are familiar at all with Frege’s work, you are most likely familiar with his groundbreaking work in the philosophy of language. You might know that Frege was a mathematician who sought to establish the covertly logical subject matter of arithmetic, a project whose demands drove Frege to his logical investigations and reflections on language. But most likely the connection between Frege’s mathematical research and his philosophy of language (...) remains elusive for you. (shrink)

avant propos This paper is basically Keenan (1992) augmented by some new types of properly polyadic quantification in natural language drawn from Moltmann (1992), Nam (1991) and Srivastav (1990). In addition I would draw the reader's attention to recent mathematical studies of polyadic quantiicationz Ben-Shalom (1992), Spaan (1992) and Westerstahl (1992). The first and third of these extend and generalize (in some cases considerably) the techniques and results in Keenan (1992). Finally I would like to acknowledge the stimulating and constructive (...) discussions ofthe earlier paper with many scholars, notably Dorit Ben-Shalom, Jaap van der Does, Hans Kamp, Uwe Mormich, Arnim von Stechow, Mats Rooth, and Ede Zimmermann. And I repeat here the acknowledgment in the earlier paper to Jim Lambek, Ed Stabler and two anonymous referees for Linguistics and Philosophy (the latter responsible for substantial improvements in the proofs - see footnote 10). (shrink)

1. There is only one rule of inference, modus ponens. This is true both in the presentations of Begriffsschrift and Grundgesetze. There are other ways of making transitions between propositions in proofs, but these are never labeled by Frege “rules of inference.” These pertain to scope of quantification, parsing of formulas, introduction of definitions, conventions for the use and replacement of the various letters, and certain structural reorganizations, ; cf. the list in Gg §48.

A frege-Russell cardinal number is a maximal class of equinumerous classes. Since anything can be numbered, A frege-Russell cardinal should contain classes whose members are cardinal numbers. This is not possible in standard set theories, Since it entails that some classes are members of members of themselves. However, A consistent set theory can be constructed in which such membership circles are allowed and in which, Consequently, Genuine frege-Russell cardinals can be defined.

Existuje překvapivě málo knih, které by se pokoušely o syntetizující pohled na analytickou filosofii. Je ovšem pravda, že ve druhé polovině našeho století se soubor filosofů, kteří se k analytické filosofii hlásí nebo kteří k ní bývají řazeni, stává natolik různorodý, že se jakákoli syntéza stává problematickou; překvapivě málo syntetizujících prací existuje ale i o ‘klasické’ analytické filosofii, to jest o analytické filosofii období zhruba od konce devatenáctého století do poloviny století dvacátého. Dejnožkova kniha je jednou z těch mála, které (...) se o něco takového pokouší, a to je třeba přivítat. Dejnožka se ovšem nesnaží podat všestranný rozbor názorů klasiků analytické filosofie; soustředí se pouze jeden aspekt jejich učení, totiž na jejich ontologii. Hned v úvodu své knihy k tomu vysvětluje, jaké opodstatnění může mít hovořit o ontologii u takového druhu filosofie, která se programově distancuje od metafyziky. Podle něj je tomu tak, že i když se někteří analytičtí filosofové někdy více či méně úspěšně vyhýbali otázkám metafyzickým (to jest otázkám po nejzákladnějších kategoriích bytí), ontologickým otázkám (to jest otázkám po povaze bytí jako takového) se v podstatě vyhnout nelze. A Dejnožka se snaží ukázat, že klasikové analytické filosofie se těmito otázkami zabývali mnohdy velice do hloubky. To je patrné zejména u Frega a Russella, kterým autor věnuje největší pozornost; avšak k těm, kteří podle Dejnožky berou ústřední otázku ontologie za svou, řadí Dejnožka i Wittgensteina i Quina (jimž se však věnuje na pouze velice omezeném prostoru - každému asi na dvanácti stránkách). (shrink)

For both Gottlob Frege and Bertrand Russell, providing a philosophical account of the concept of number was a central goal, pursued along similar logicist lines. In the present paper, I want to focus on a particular aspect of their accounts: their definitions, or reconstructions, of the natural numbers as equivalence classes of equinumerous classes. In other words, I want to examine what is often called the "Frege-Russell conception of the natural numbers" or, more briefly, the Frege-Russell numbers. My main concern (...) will be to determine the precise sense in which this conception was, or could be, meant to constitute an analysis.1 I will be mostly concerned with Frege’s views on the matter; but Russell will come up along the way, for illustration and comparison, as will some recent neo-Fregean proposals and results. The structure of the paper is as follows: In the first section, I sketch Frege's general approach. Next, I differentiate several kinds, or modes, of analysis, as further background. In the third section, I zero in on the equivalence class construction, raising the question of why it might, from a Fregean point of view, be seen as 'the right' construction, thus as an analysis in a strong sense. In the fourth section, I provide a contrasting, more conventionalist view of the matter, often associated with the Carnapian notion of explication, and expressed in some remarks by Russell. I then discuss the motivation for the Frege-Russell numbers in more depth. In the sixth section, I introduce a neo-Fregean alternative, to be examined along similar lines. Finally, I reflect further on the significance of the kinds of arguments available in this connection. (shrink)

Frege's main contributions to logic and the philosophy of mathematics are, on the one hand, his introduction of modern relational and quantificational logic and, on the other, his analysis of the concept of number. My focus in this paper will be on the latter, although the two are closely related, of course, in ways that will also play a role. More specifically, I will discuss Frege's logicist reconceptualization of the natural numbers with the goal of clarifying two aspects: the motivations (...) for its core ideas; the step-by-step development of these ideas, from Begriffsschrift through Die Grundlagen der Arithmetik and Grundgesetze der Arithmetik to Frege's very last writings, indeed even beyond those, to a number of recent "neo-Fregean" proposals for how to update them. One main development, or break, in Frege's views occurred after he was informed of Russell's antinomy. His attempt to come to terms with this antinomy has found some attention in the literature already. It has seldom been analyzed in connection with earlier changes in his views, however, partly because those changes themselves have been largely ignored. Nor has it been discussed much in connection with Frege's basic motivations, as formed in reaction to earlier positions. Doing both in this paper will not only shed new light on his response to Russell's antinomy, but also on other aspects of his views. In addition, it will provide us with a framework for comparing recent updates of these views, thus for assessing the remaining attraction of Frege's general approach. I will proceed as follows: In the first part of the paper (§1.1 and §1.2), I will consider the relationship of Frege's conception of the natural numbers to earlier conceptions, in particular to what I will call the "pluralities conception", thus bringing into sharper focus his core ideas and their motivations. In the next part (§2.1 and §2.2), I will trace the order in which these ideas come up in Frege's writings, as well as the ways in which his position gets modified along the way, both before and after Russell's antinomy.. (shrink)

Since there are non-sortal predicates Frege’s attempt to derive Arithmetic from Logic stumbles at its very first step. There are properties without a number, so the contingency of that condition shows Frege’s definition of zero is not obtainable from Logic. But Frege made a crucial mistake about concepts more generally which must be remedied, before we can be clear about those specific concepts which are numbers.

The four volumes of this collection bring together some of the major contributions to the literature on Gottlob Frege (1848-1925), one of the most formative influences on the course of philosophy during the last hundred years. The first volume provided general assessments of Frege's work and examined its historical context. The present volume deals with Frege's contributions to logic and the foundations of mathematics. The essays are arranged in order of their first publication, providing insight into the historical evolution of (...) the Frege literature. Annotation copyright by Book News, Inc., Portland, OR. (shrink)

There can be no doubt about the value of Frege's contributions to the philosophy of mathematics. First, he invented quantification theory and this was the first step toward making precise the notion of a purely logical deduction. Secondly, he was the first to publish a logical analysis of the ancestral R* of a relation R, which yields a definition of R* in second-order logic.1 Only a narrow and arid conception of philosophy would exclude these two achievements. Thirdly and very importantly, (...) the discussion in §§58-60 of the G r u n d l a g e n defends a conception of mathematical existence, to be found in Cantor (1883) and later in the writings of Dedekind and Hilbert, by basing it upon considerations about meaning which have general application, outside mathematics.2.. (shrink)

A Frege proof systemFis any standard system of prepositional calculus, e.g., a Hilbert style system based on finitely many axiom schemes and inference rules. An Extended Frege systemEFis obtained fromFas follows. AnEF-sequence is a sequence of formulas ψ1, …, ψκsuch that eachψiis either an axiom ofF, inferred from previous ψuand ψv by modus ponens or of the formq↔ φ, whereqis an atom occurring neither in φ nor in any of ψ1,…,ψi−1. Suchq↔ φ, is called an extension axiom andqa new extension (...) atom. AnEF-proof is anyEF-sequence whose last formula does not contain any extension atom. In [12], S. A. Cook and R. Reckhow proved that the pigeonhole principlePHPhas a simple polynomial sizeEF-proof and conjectured thatPHPdoes not admit polynomial sizeF-proof. In [5], S. R. Buss refuted this conjecture by furnishing polynomial sizeF-proof forPHP. Since then the important separation problem of polynomial sizeFand polynomial sizeEFhas not shown any progress.In [11], S. A. Cook introduced the systemPV, a free variable equational logic whose provable functional equalities are ‘polynomial time verifiable’ and showed that the metamathematics ofFandEFcan be developed inPVand the soundness ofEFproved inPV. In [3], S. R. Buss introduced the first order systemand showed thatis essentially a conservative extension ofPV. There he also introduced a second order system. (shrink)