The Frege-Russell view is that existence is a second-order property rather than a property of individuals. One of the most compelling arguments for this view is based on the premise that there is an especially close connection between existence and number. The most promising version of this argument is by C.J.F Williams (1981, 1992). In what follows, I argue that this argument fails. I then defend an account according to which both predications of number and existence attribute properties to individuals.

Frege's conception of the logical categories has vexed commentators for decades. In this dissertation, I argue that it revolves around two forms of internality. The first is the internality of its use in the expression of judgment to the sign. A proper understanding of that internality reveals how Frege's philosophical logic cannot be fit into the framework given by the contemporary syntax/semantics distinction. The second is the internality that obtains between the way in which Begriffsschrift signs stratify into different categories, (...) on the one hand, and the way in which the realm of Bedeutungen stratifies into logical categories, on the other hand. A proper understanding of this internality reveals how Frege's conception of the relation between language and the world is neither a form of realism nor a form of linguistic idealism. To come to understand Frege's conception of the logical categories, is to come to understand both these forms of internality by coming to understand how they hang together. (shrink)

A central dispute in understanding Frege’s philosophy concerns how the sense of a complex expression relates to the senses of its component expressions. According to one reading, the sense of a complex expression is a whole built from the senses of the component expressions. On this interpretation, Frege is an early proponent of structured propositions. A rival reading says that senses compose by functional application: the sense of a complex expression is the value of the function denoted by its functional (...) component for the arguments denoted by its remaining components. I argue that two non-negotiable Fregean theses entail that senses compose by functional application. One thesis is that referents compose by functional application. The other thesis is that an expression in an indirect context refers to its customary sense. (shrink)

It is well known that the circumflex notation used by Russell and Whitehead to form complex function names in Principia Mathematica played a role in inspiring Alonzo Church's “lambda calculus” for functional logic developed in the 1920s and 1930s. Interestingly, earlier unpublished manuscripts written by Russell between 1903–1905—surely unknown to Church—contain a more extensive anticipation of the essential details of the lambda calculus. Russell also anticipated Schönfinkel's combinatory logic approach of treating multiargument functions as functions having other functions as value. (...) Russell’s work in this regard seems to have been largely inspired by Frege’s theory of functions and “value-ranges”. This system was discarded by Russell due to his abandonment of propositional functions as genuine entities as part of a new tack for solving Russell’s paradox. In this article, I explore the genesis and demise of Russell’s early anticipation of the lambda calculus. (shrink)

I trace changes to Frege's understanding of numbers, arguing in particular that the view of arithmetic based in geometry developed at the end of his life (1924–1925) was not as radical a deviation from his views during the logicist period as some have suggested. Indeed, by looking at his earlier views regarding the connection between numbers and second-level concepts, his understanding of extensions of concepts, and the changes to his views, firstly, in between Grundlagen and Grundgesetze, and, later, after learning (...) of Russell's paradox, this position is a natural position for him to have retreated to, when properly understood. (shrink)

We argue that Wittgenstein’s philosophical perspective on Gödel’s most famous theorem is even more radical than has commonly been assumed. Wittgenstein shows in detail that there is no way that the Gödelian construct of a string of signs could be assigned a useful function within (ordinary) mathematics. — The focus is on Appendix III to Part I of Remarks on the Foundations of Mathematics. The present reading highlights the exceptional importance of this particular set of remarks and, more specifically, emphasises (...) its refined composition and rigorous internal structure. (shrink)

(1) An introduction to the principles of conceptual modelling, combinatorial heuristics and epistemological history; (2) the examination of a number of perennial epistemological-methodological schemata: conceptual spaces and blending theory; ars inveniendi and ars demonstrandi; the two modes of analysis and synthesis and their relationship to ars inveniendi; taxonomies and typologies as two fundamental epistemic structures; extended cognition, cognitio symbolica and model-based reasoning; (3) Plato’s notions of conceptual spaces, conceptual blending and hypothetical-analogical models (paradeigmata); (4) Ramon Llull’s concept analysis and combinatoric (...) spaces; (5) Gottfried Leibniz’s development of compositional analysis and synthesis as a general modelling method and a paradigm for ars inveniendi; (6) Fritz Zwicky’s revival of the morphological method of analysis and construction, and its subsequent computerised applications. (shrink)

Logic played an important role in Wittgenstein’s work over the entire period of his philosophizing, from both the point of view of the philosopher of logic and that of the logician. Besides logical analysis, there is another kind of logical activity that characterizes Wittgenstein’s philosophical work after a certain point during his experience as a soldier and, later, as an officer in the First World War – if not earlier. This other kind of logical activity has to do with what (...) appears to be the literary form of Wittgenstein’s philosophical prose, and it is likely to be seen as the most modernist feature of his preoccupation with logic. (shrink)

It is often thought that endowing a demonstrative with a Fregean sense leaves no room for maintaining that it is also a rigid designator. In addition, some philosophers claim that indexicals - surely the paradigms of singular reference - pose a serious threat to the Fregean sense/ reference approach as they do not comply with the view that singular terms have Fregean senses. In this paper I argue that neither of these is true.

semantic minimalism and moderte contextualism.

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)

What is logical relevance? Anderson and Belnap say that the “modern classical tradition [,] stemming from Frege and Whitehead-Russell, gave no consideration whatsoever to the classical notion of relevance.” But just what is this classical notion? I argue that the relevance tradition is implicitly most deeply concerned with the containment of truth-grounds, less deeply with the containment of classes, and least of all with variable sharing in the Anderson–Belnap manner. Thus modern classical logicians such as Peirce, Frege, Russell, Wittgenstein, and (...) Quine are implicit relevantists on the deepest level. In showing this, I reunite two fields of logic which, strangely from the traditional point of view, have become basically separated from each other: relevance logic and diagram logic. I argue that there are two main concepts of relevance, intensional and extensional. The first is that of the relevantists, who overlook the presence of the second in modern classical logic. The second is the concept of truth-ground containment as following from in Wittgenstein’s Tractatus. I show that this second concept belongs to the diagram tradition of showing that the premisses contain the conclusion by the fact that the conclusion is diagrammed in the very act of diagramming the premisses. I argue that the extensional concept is primary, with at least five usable modern classical filters or constraints and indefinitely many secondary intensional filters or constraints. For the extensional concept is the genus of deductive relevance, and the filters define species. Also following the Tractatus, deductive relevance, or full truth-ground containment, is the limit of inductive relevance, or partial truth-ground containment. Purely extensional inductive or partial relevance has its filters or species too. Thus extensional relevance is more properly a universal concept of relevance or summum genus with modern classical deductive logic, relevantist deductive logic, and inductive logic as its three main domains. (shrink)

This article examines the development of Russell's treatment of propositions, in relation to the topic of psychologism. In the first section, we outline the concept of psychologism, and show how it can arise in relation to theories of the nature of propositions. Following this, we note the anti-psychologistic elements of Russell's thought dating back to his idealist roots. From there, we sketch the development of Russell's theory of the proposition through a number of its key transitions. We show that Russell, (...) in responding to a variety of different problems relating to the proposition, chose to resolve these problems in ways that continually made concessions to psychologism. (shrink)

Thorough a detailed analysis of version III of Gödel's Is mathematics syntax of language?, we propose a new interpretation of Gödel's criticism against the conventionalist point of view in mathematics. When one reads carefully Gödel's text, it brings out that, contrary to the opinion of some commentators, Gödel did not overlook the novelty of Carnap's solution, and did not criticise him from an old-fashioned conception of science. The general aim of our analysis is to restate the Carnap/Gödel debate in the (...) Fregean heritage. We stress the way both of them try to answer, from different Fregean perspectives, to the question of the nature of logic and mathematics in knowledge. (shrink)

In the philosophy of mathematical practice, the aim is to understand the various aspects of this practice. Even though definitions are a central element of mathematical practice, the study of this aspect of mathematical practice is still in its infancy. In particular, there is little empirical evidence to substantiate claims about definitions in practice. In this article, we address this gap by reporting on an empirical investigation on how mathematicians create definitions and which roles and properties they attribute to them. (...) On the basis of interviews with thirteen research mathematicians, we provide a broad range of relevant aspects of definitions. In particular, we address various roles of definitions and show that definitions are not just a product of mathematical factors, but also of social and contingent factors. Furthermore, we provide concrete examples of how mathematicians interact and think about definition. This broad empirical basis with a variety of examples provides an optimal starting point for future investigations into definitions in mathematical practice. (shrink)

The paper focuses on Gottlob Frege’s so called Context Principle (CP hereafter), which counts as one of the most controversial points of his philosophy. Due to its importance and centrality in Frege’s thought, a detailed discussion of the principle requires a detailed analysis of almost all aspects of his philosophy. Obviously, such a task cannot be successfully accomplished here. Thus I limit myself to address only two questions concerning the CP: what role does the principle play (in Grundlagen) and how (...) can we interpret it. Addressing the first problem is required in order to address the second. Most authors interpreted CP from the perspective of Frege’s later distinction between sense and reference, which I will call the ‘semantic interpretation’. Although I accept this perspective as valuable and important, I will initially inverse the action and I will try to approach CP, and generally Grundlagen, in a more natural way, contextually, namely setting them in the initial logicist plan of the Begriffschrift. Finally, I will try to provide an interpretation concerning the alleged conflict between CP and Frege’s compositionality thesis such that they could coherently stay together. (shrink)

RÉSUMÉ: L'objectif de cet article est essentiellement négatif. Suivant en cela Dummett, j'introduis deux manières attrayantes d'interpréter le Sinn original de Frege, que j'appelle respectivement la doctrine du sens privé et la doctrine du sens public. Je montre que ces conceptions ne peuvent être utilisées dans le traitement frégéen de l'oratio obliqua. Il faut donc abandonner soit l'interprétation du Sinn par Dummett, soit le traitement frégéen de l'oratio obliqua.

C. I. Lewis (I883-I964) was the first major figure in history and philosophy of logic—-a field that has come to be recognized as a separate specialty after years of work by Ivor Grattan-Guinness and others (Dawson 2003, 257).Lewis was among the earliest to accept the challenges offered by this field; he was the first who had the philosophical and mathematical talent, the philosophical, logical, and historical background, and the patience and dedication to objectivity needed to excel. He was blessed with (...) many fortunate circumstances, not least of which was entering the field when mathematical logic, after only six decades of toil, had just reaped one of its most important harvests with publication of the monumental Principia Mathematica. It was a time of joyful optimism which demanded an historical account and a sober philosophical critique. Lewis was one of the first to apply to mathematical logic the Aristotelian dictum that we do not understand a living institution until we see it growing from its birth. (shrink)

The goal of this paper is to show that a cognitivist–externalist view about moral judgment is compatible with a key intuition that motivates non-cognitivist expressivism. This is the intuition that normative judgments have a close connection to action that ordinary “descriptive factual beliefs” do not have, or, as James Dreier has suggested, that part of the fundamental role of normative judgment is to motivate. One might think that cognitivist–externalist positions about normative judgment are committed to viewing normative judgments as having (...) the same role in our psychology as ordinary descriptive factual beliefs. This paper argues to the contrary. It restricts attention to moral judgments. It develops an account of moral belief according to which, first, moral beliefs are representational cognitive states that have the same basic nature as ordinary descriptive factual beliefs. Yet, second, their fundamental role is such that, when all goes well, moral beliefs mesh with our moral policies to motivate action. The paper draws on a society-centered account of the grounding of morality, a distinction between “basic” and “internal” ways of thinking of the moral properties, and a hybrid account of the “meaning” of moral predicates, called “realist-expressivism.”. (shrink)

Conceptual realism begins with a conceptualist theory of the nexus of predication in our speech and mental acts, a theory that explains the unity of those acts in terms of their referential and predicable aspects. This theory also contains as an integral part an intensional realism based on predicate nominalization and a reflexive abstraction in which the intensional contents of our concepts are “object”-ified, and by which an analysis of predication with intensional verbs can be given. Through a second nominalization (...) of the common names that are part of conceptual realism’s theory of reference (via quantifier phrases), the theory also accounts for both plural reference and predication and mass noun reference and predication. Finally, a separate nexus of predication based on natural kinds and the natural properties and relations nomologically related to those natural kinds, is also an integral part of the framework of conceptual realism. (shrink)

The problematic features of Quine's set theories NF and ML are a result of his replacing the higher-order predicate logic of type theory by a first-order logic of membership, and can be resolved by returning to a second-order logic of predication with nominalized predicates as abstract singular terms. We adopt a modified Fregean position called conceptual realism in which the concepts (unsaturated cognitive structures) that predicates stand for are distinguished from the extensions (or intensions) that their nominalizations denote as singular (...) terms. We argue against Quine's view that predicate quantifiers can be given a referential interpretation only if the entities predicates stand for on such an interpretation are the same as the classes (assuming extensionality) that nominalized predicates denote as singular terms. Quine's alternative of giving predicate quantifiers only a substitutional interpretation is compared with a constructive version of conceptual realism, which with a logic of nominalized predicates is compared with Quine's description of conceptualism as a ramified theory of classes. We argue against Quine's implicit assumption that conceptualism cannot account for impredicative concept-formation and compare holistic conceptual realism with Quine's class Platonism. (shrink)

According to a view going back to Plato, the aim of philosophy is to acquire knowledge and there is a method to acquire knowledge, namely a method of discovery. In the last century, however, this view has been completely abandoned, the attempt to give a rational account of discovery has been given up, and logic has been disconnected from discovery. This paper outlines a way of reconnecting logic with discovery.

According to a view going back to Plato, the aim of philosophy is to acquire knowledge and there is a method to acquire knowledge, namely a method of discovery. In the last century, however, this view has been completely abandoned, the attempt to give a rational account of discovery has been given up, and logic has been disconnected from discovery. This paper outlines a way of reconnecting logic with discovery.

The paper distinguishes between two kinds of mathematics, natural mathematics which is a result of biological evolution and artificial mathematics which is a result of cultural evolution. On this basis, it outlines an approach to the philosophy of mathematics which involves a new treatment of the method of mathematics, the notion of demonstration, the questions of discovery and justification, the nature of mathematical objects, the character of mathematical definition, the role of intuition, the role of diagrams in mathematics, and the (...) effectiveness of mathematics in natural science. (shrink)

In the past century the received view of definition in mathematics has been the stipulative conception, according to which a definition merely stipulates the meaning of a term in other terms which are supposed to be already well known. The stipulative conception has been so absolutely dominant and accepted as unproblematic that the nature of definition has not been much discussed, yet it is inadequate. This paper examines its shortcomings and proposes an alternative, the heuristic conception.

Many commentators have attempted to say, more clearly than Wittgenstein did in his Tractatus logico-philosophicus, what sort of things the ‘simple objects’ spoken of in that book are. A minority approach, but in my view the correct one, is to reject all such attempts as misplaced. The Tractarian notion of an object is categorially indeterminate: in contrast with both Frege's and Russell's practice, it is not the logician's task to give a specific categorial account of the internal structure of elementary (...) propositions or atomic facts, nor, correlatively, to give an account of the forms of simple objects. The few commentators who have hitherto maintained this view have mainly devoted themselves to establishing that this was Wittgenstein's intention, and do not much address the question why Wittgenstein held that it is not the logician's business to say what the objects are. The present paper means to fill this lacuna by placing this view in the context of the Tractatus's treatment of logic generally, and in particular by connecting it with Wittgenstein's treatment of generality and with his reaction to Russell's approach to logical form. (shrink)

L'A. étudie la théorie classique du jugement telle qu'elle apparait dans «La logique» de A. Arnauld et P. Nicole et oppose la sémantique des termes généraux de Port-Royal à celles de Kant et Frege.

Focusing on the 'today'/'yesterday' case, I argue that Perry is wrong in accounting for and explaining indexical belief states in terms of Kaplanian characters and in taking these states to be internal (narrow) mental states inside the subject's mind. It is shown that this view is at odds with Perry's own reliance on remembering a past day as a necessary condition for retaining a belief about it. As a better tool for explaining appropriate indexical beliefs, I offer an alternative which (...) is neo-Fregean in that it takes senses or modes of presentation as playing only a cognitive, not a semantic role. It, however, takes remembering a past day as necessary for retaining a belief about it, rather than keeping track of time as urged by Evans. I also consider unfeasible Evans's further requirement which he takes over from Frege: that in order to retain a belief about a certain past day we need to think of it now under the same mode of presentation as we did on that very day. (shrink)

In this paper I argue that propositionalism is what generates a tension between referentialism and harmony. Harmony can be preserved if we replace propositionalism by centred referentialism, according to which referential thoughts and utterances about an object have descriptive contents that must be evaluated relative to a world centred on that object at the relevant time. By disentangling truth-conditions and contents, this move allows us to dissolve the tension between referentialism and descriptivism. The view that emerges has three main components: (...) the truth-conditions of a referential utterance or thought involves its referent ; its reference is determined by causal relations of acquaintance in the context of use ; and its cognitive value is fully explained by associated descriptions or truth-conditional contents. (shrink)

This essay examines Frege's reaction to Russell's Paradox and his views about the grounding of existence claims in mathematics. It is argued that Frege's strict requirements on existential proofs would rule out the attempt to ground arithmetic in. It is hoped that this discussion will help to clarify the ways in which Frege's position is both coherent and significantly different from the neo-logicist position on the issues of: what's required for proofs of existence; the connection between models, consistency, and existence; (...) and the prospects for a logical grounding of arithmetic in the wake of the paradox. (shrink)

In 1893 and 1903, two volumes of the most important of Frege’s works Grundegezte der Arithmetik were published. This period can be called the peak of Frege’s logicism. Although the subject of truth in Frege’s logical and philosophical works has been repeatedly investigated, there is a lack of studies on his view in this period, especially in Polish literature. In this article, therefore, I carry out the following research task: to collect and order Frege’s statements about truth during the period (...) of publishing the two volumes of Grundegezte der Arithmetik. I refer to the texts published during Frege’s life, published posthumously and his correspondence. Particularly noteworthy are: Grundegezte der Arithmetik and the unpublished Logik. That is why there are two separate sections dedicated to these two texts, whereas the discussions of truth from other texts are grouped thematically: the problem of antinomy, geometry, expression of generality, and others. The subject of truth appears there in relation to logic, philosophy of language, philosophy of logic, philosophy of mathematics and ontology. (shrink)

In this paper we motivate and develop a new approach to predicates of personal taste within the framework of semantic relativism. Our primary goal is to explain faultless disagreement—the phenomenon where two parties disagree, yet both have uttered something true—which is often thought to arise from the use of predicates of personal taste. We combine semantic relativism with an expressivist semantics to yield a novel hybrid theory which we call _Expressive-Relativism_. We motivate the theory by rehearsing a famous objection to (...) Relativism from Frege which we interpret as severing the connection between contradiction and disagreement for relativists. Endorsing the objection, we respond by enriching relativism with an expressivist component which explains disagreement over matters of taste as a refusal to share perspectives rather than as resting on contradiction. (shrink)

Frege analyzed the grammatical subject-term 'S' in quantified subject-predicate sentences, 'q S are P', as being logically predicative. This is in contrast to Aristotelian Logic, according to which it is a logical subject-term, like the proper name 'a' in 'a is P' – albeit a plural one, designating many particulars. I show that Frege's arguments for his analysis are unsound, and explain how he was misled to his position by the mathematical concept of function. If common nouns in this grammatical (...) subject position are indeed logical subject-terms, this should require a thorough reevaluation of the adequacy of Frege's Predicate Calculus as a tool for the analysis of the logic and semantics of natural language. (shrink)

Peirce seems to maintain two incompatible theses: that a sentence is multiply analyzable into subject and predicate, and that a sentence is uniquely analyzable as a combination of rhemata of first intention and rhemata of second intention. In this paper it is argued that the incompatibility disappears as soon as we distinguish, following Dummett’s work on Frege, two distinct notions of analysis: ‘analysis’ proper, whose purpose is to display the manner in which the sense of a sentence is determined by (...) the senses of its constituent parts, and ‘decomposition’, which is the process of dividing a sentence into a predicate and a subject, and whose purpose is to both to explain how quantified sentences are constructed and to evidence a pattern within a sentence which it shares with other sentences. (shrink)

In this symposium contribution I critically review the first two chapters, on Frege, in Volume 1 of The Analytic Tradition in Philosophy by Scott Soames.

Quine’s philosophy comprises a bewildering set of views whose integrating principle is his "confirmed extensionalism". The paper offers a historical as well as an intellectual reconstruction of extensionalism. Traditional extensionalism (Boole) freed logic from Aristotelian essentialism that had inhibited the development of logic. Quine’s confirmed extensionalism is the acceptance, as a matter of course, of the validity of Frege’s criticism of [Boole’s] extensionalism. His confirmed extensionalism is a generalized version of the philosophy of science known as conventionalism. As such, it (...) places the advancement of science outside the province of science proper. It is, thus, at odds with Quine’s repeated expressions of alliance with the Popperian (hypothetico-deductive) model of science. (shrink)

The origins of proof-theoretic semantics lie in the question of what constitutes the meaning of the logical connectives and its response: the rules of inference that govern the use of the connective. However, what if we go a step further and ask about the meaning of a proof as a whole? In this paper we address this question and lay out a framework to distinguish sense and denotation of proofs. Two questions are central here. First of all, if we have (...) two different derivations, does this always lead to a difference, firstly, in sense, and secondly, in denotation? The other question is about the relation between different kinds of proof systems with respect to this distinction. Do the different forms of representing a proof necessarily correspond to a difference in how the inferential steps are given? In our framework it will be possible to identify denotation as well as sense of proofs not only within one proof system but also between different kinds of proof systems. Thus, we give an account to distinguish a mere syntactic divergence from a divergence in meaning and a divergence in meaning from a divergence of proof objects analogous to Frege’s distinction for singular terms and sentences. (shrink)

This paper explores the nature of the concept of truth. It does not offer an analysis or definition of truth, or an account of how it relates to other concepts. Instead, it explores what sort of concept truth is by considering what sorts of thoughts it enables us to think. My conclusion is that truth is a part of each and every propositional thought. The concept of truth is therefore best thought of as the ability to token propositional thoughts. I (...) explore what implications this view has for existing accounts of concepts, and argue that truth is a concept unlike any other. (shrink)

Conceptual primitivism is the view that truth is among our most basic and fundamental concepts. It cannot be defined, analyzed, or reduced into concepts that are more fundamental. Primitivism is opposed to both traditional attempts at defining truth (in terms of correspondence, coherence, or utility) and deflationary theories that argue that the notion of truth is exhausted by means of the truth schema. Though primitivism might be thought of as a view of last resort, I believe that the view is (...) independently attractive, and can be argued for directly. In this paper I offer what I take to be the strongest argument in favor of conceptual primitivism, which relies upon the Fregean doctrine of the omnipresence of truth. (shrink)

I argue that the concept of direction of fit is best seen as picking out a certain inferential property of a psychological attitude. The property in question is one that believing shares with assuming and fantasizing and fails to share with desire. Unfortunately, the standard analysis of DOF obscures this fact because it conflates two very different properties of an attitude: that in virtue of which it displays a certain DOF, and that in virtue of which it displays certain revision (...) conditions. I claim that the latter corresponds with the aim of an attitude, not its DOF. In order to remedy this failure of the standard analysis, I offer an alternative account of DOF, which I refer to as the two-content analysis. (shrink)

This paper explores a pair of puzzling and controversial topics in the history of late nineteenth-century philosophy: the psychologism debates, and the nature of neo-Kantianism. Each is sufficientl...