Esta enciclopédia abrange, de uma forma introdutória mas desejavelmente rigorosa, uma diversidade de conceitos, temas, problemas, argumentos e teorias localizados numa área relativamente recente de estudos, os quais tem sido habitual qualificar como «estudos lógico-filosóficos». De uma forma apropriadamente genérica, e apesar de o território teórico abrangido ser extenso e de contornos por vezes difusos, podemos dizer que na área se investiga um conjunto de questões fundamentais acerca da natureza da linguagem, da mente, da cognição e do raciocínio humanos, bem (...) como questões acerca das conexões destes com a realidade não mental e extralinguística. A razão daquela qualificação é a seguinte: por um lado, a investigação em questão é qualificada como filosófica em virtude do elevado grau de generalidade e abstracção das questões examinadas (entre outras coisas); por outro, a investigação é qualificada como lógica em virtude de ser uma investigação logicamente disciplinada, no sentido de nela se fazer um uso intenso de conceitos, técnicas e métodos provenientes da disciplina de lógica. O agregado de tópicos que constitui a área de estudos lógico-filosóficos é já visível, pelo menos em parte, no Tractatus Logico-Philosophicus de Ludwig Wittgenstein, uma obra publicada em 1921. E uma boa maneira de ter uma ideia sinóptica do território disciplinar abrangido por esta enciclopédia, ou pelo menos de uma porção substancial dele, é extrair do Tractatus uma lista dos tópicos mais salientes aí discutidos; a lista incluirá certamente tópicos do seguinte género, muitos dos quais se podem encontrar ao longo desta enciclopédia: factos e estados de coisas; objectos; representação; crenças e estados mentais; pensamentos; a proposição; nomes próprios; valores de verdade e bivalência; quantificação; funções de verdade; verdade lógica; identidade; tautologia; o raciocínio matemático; a natureza da inferência; o cepticismo e o solipsismo; a indução; as constantes lógicas; a negação; a forma lógica; as leis da ciência; o número. (shrink)

I argued that Frege does not have a metatheory in the following sense: the justifications he offers for his basic laws and rules of inference neither employ nor require a truth-predicate or metalinguistic variables. In ‘Does Frege Use a Truth-predicate in his "Justification" of the Laws of Logic?’, Dirk Greimann disputes this. As Greimann interprets Frege, (i) Frege's remarks commit him to giving a metatheoretic justification of the basic laws and rules of his logic, and (ii) Frege actually gives such (...) a justification in the early sections of Grundgesetze—although the truth-predicate that Frege employs is a non-standard one: it is neither a predicate that holds of all and only true sentences nor a predicate that holds of all and only true thoughts. I argue that Greimann's interpretation is not, in the end, true to the text, and that his non-standard view of what is required of a Tarskian truth-predicate is ultimately not viable. (shrink)

In the opening to his late essay, Der Gedanke, Frege asserts without qualification that the word "true" points the way for logic. But in a short piece from his Nachlass entitled "My Basic Logical Insights", Frege writes that the word true makes an unsuccessful attempt to point to the essence of logic, asserting instead that "what really pertains to logic lies not in the word "true" but in the assertoric force with which the sentence is uttered". Properly understanding what Frege (...) takes to be at issue here is crucial for understanding his conception of logic and, in particular, what he takes to be its normative status vis-à-vis judgement, assertion, and inference. In this paper, I focus my attention on clarifying the latter claim and Frege's motivations for making it, exposing what I take to be a fundamental tension in Frege's conception of logic. Finally, I discuss whether Frege's deployment of the horizontal in his mature Begriffsschrift helps to resolve this tension. (shrink)

Between April and November 1912, Bertrand Russell and Ludwig Wittgenstein were engaged in a joint philosophical program. Wittgenstein‘s meeting with Gottlob Frege in December 1912 led, however, to its dissolution – the joint program was abandoned. Section 2 of this paper outlines the key points of that program, identifying what Russell and Wittgenstein each contributed to it. The third section determines precisely those features of their collaborative work that Frege criticized. Finally, building upon the evidence developed in the preceding two (...) sections, section 4 recasts along previously undeveloped lines Wittgenstein‘s logical–philosophical discoveries in the two years following his encounter with Frege in 1912. The paper concludes, in section 5, with an overview of the dramatic consequences the Frege-Wittgenstein critique had for Russell‘s philosophical development. (shrink)

There are currently two readings of Tractatus, the metaphysical and the therapeutic. I argue that neither of these is satisfactory. I develop a third reading, the elucidatory reading. This shares the therapeutic interpretation’s emphasis on the idea that Wittgenstein’s remarks are intended to work on the reader, but instead of seeing these remarks as directed (problematically) at revealing their own nonsensical status, I take the remarks to be aimed at bringing a certain order to the reader’s perception of language. The (...) point of this order, and the only test of it, is that it enables the philosophical problems to disappear. In particular, it dispels philosophical puzzlement concerning the status of logic, the relation between language and the world, and the relation between thought and language. (shrink)

This paper argues that Wittgenstein, both early and late, rejects the idea that the logically simpler and more fundamental case is that of “the mere sign” and that what a meaningful symbol is can be explained through the elaboration of an appropriately supplemented conception of the sign: the sign plus something (say, an interpretation or an assignment of meaning). Rather the sign, in the logically fundamental case of its mode of occurrence, is an internal aspect of the symbol. The Tractatus (...) puts this point as follows: “The sign is that in the symbol which is perceptible by the senses.” Conversely, this means that it is essential to a symbol – to what a symbol is – that it have an essentially perceptible aspect. For Wittgenstein there is no privileged direction of explanatory priority between symbol and sign here: without signs there are no symbols (hence without language there is no thought) and without some sort of relation to symbols there are no signs (hence the philosopher’s concept of the supposedly “merely linguistic” presupposes an internal relation to symbols). (shrink)

The positions of Frege, Russell and Wittgenstein on the priority of complexes over (propositional) functions are sketched, challenging those who take the "judgment centered" aspects of the Tractatus to be inherited from Frege not Russell. Frege's views on the priority of judgments are problematic, and unlike Wittgenstein's. Russell's views on these matters, and their development, are discussed in detail, and shown to be more sophisticated than usually supposed. Certain misreadings of Russell, including those regarding the relationship between propositional functions and (...) universals, are exposed. Wittgenstein's and Russell's views on logical grammar are shown to be very similar. Russell's type theory does not countenance types of genuine entities nor metaphysical truths that cannot be put into words, contrary to conventional wisdom. I relate this to the debate over "inexpressible truths" in the Tractatus. I lastly comment on the changes to Russell's views brought about by Wittgenstein's influence. (shrink)

The concept of empiricism evokes both a historical tradition and a set of philosophical theses. The theses are usually understood to have been developed by Locke, Berkeley, and Hume. But these figures did not use the term “empiricism,” and they did not see themselves as united by a shared epistemology into one school of thought. My dissertation analyzes the debate that elevated the concept of empiricism (and of an empiricist tradition) to prominence in English-language philosophy. -/- In the 1870s and (...) ’80s a lively debate about psychology emerged. Neo-Kantian idealists criticized the very idea that the mind can be studied scientifically. A group of philosopher-psychologists responded, often in Mind. They were among the first to call themselves “empiricists,” arguing that psychology could provide a scientific basis for philosophical progress. Idealists held that empirical psychology depended on premises developed by Locke, Berkeley, and Hume. These premises were allegedly absurd because they rendered ideas of extension, as well as other ideas crucial to natural science, unreal. Those who wanted to advance psychology towards becoming a legitimate science were forced to engage these philosophical attacks, while at the same time to develop empirical theories that could successfully explain some characteristics of experience. I show how James’s theory of space perception accomplished both tasks. -/- In developing this theory, James found he had to reject the Lockean notion that reality is associated with passively-registered sensations. James also abandoned Berkeley and Hume’s claim that ideas are ultimately derived from atomic sensations. Instead, James presented experimental evidence that sensation is a continuous stream. The mind must actively parse this stream if it is to gain a coherent representation of its environment. I argue that James’s stream-of-thought thesis served as a presupposition of his entire psychology. The thesis showed how the labor of investigating the mind could be divided between philosophers and scientists, and in a manner sensitive to the concerns of both. The stream thesis also provided a scientific basis for a new philosophical empiricism that, I argue, has a hidden legacy in the history of analytic philosophy. (shrink)

Although the economic thought of Marshall and Pigou was united by ethical positions broadly considered utilitarian, differences in their intellectual milieu led to degrees of difference between their respective philosophical visions. This change in milieu includes the influence of the little understood period of transition from the early idealist period in Great Britain, which provided the context to Marshall’s intellectual formation, and the late British Idealist period, which provided the context to Pigou’s intellectual formation. During this latter period, the pervading (...) Hegelianism and influences of naturalism arising from the ideas of Charles Darwin and Herbert Spencer were challenged by Hermann Lotze, a key transitional thinker influencing the Neo-Kantian movement, who recognised significant limits of naturalism, on the one hand, and the metaphysical tenor of absolute idealism, on the other, and attempted to provide a balance between the two. The goal of this paper is to make the provisional case for the argument that Pigou’s views on ethics were not only directly influenced by utilitarian thinkers like Mill and Sidgwick, but they were also indirectly influenced by Hermann Lotze, via the influence of the Neo- Kantian movement on late British idealism. To that end, Pigou’s essays in The Trouble with Theism (1908), including his sympathetic consideration of the ethics of Friedrich Nietzsche, reflect the influence of Lotze indirectly through the impact at Cambridge of: James Ward’s critique of associationist psychology, and consideration of the limits of naturalism including the critique of evolutionary ethics; Bertrand Russell’s rejection of neo-Hegelianism and, together with Alfred North Whitehead, the development of Logicism; and G.E. Moore’s critique of utilitarian ethics on the basis of the naturalistic fallacy and the development of his own intuitionist system of ethics. (shrink)