Mathieu Marion

The development of symbolic logic is often presented in terms of a cumulative story of consecutive innovations that led to what is known as modern logic. This narrative hides the difficulties that this new logic faced at first, which shaped its history. Indeed, negative reactions to the emergence of the new logic in the second half of the nineteenth century were numerous and we study here one case, namely logic at Oxford, where one finds Lewis Carroll, a mathematical teacher who promoted symbolic logic, and John Cook Wilson, the Wykeham Professor of Logic who notoriously opposed it. An analysis of their disputes on the topic of logical symbolism shows that their opposition was not as sharp as it might look at first, as Cook Wilson was not so much opposed to the « symbolic » character of logic, but the intrusion of mathematics and what he perceived to be the futility of some of its problems, for logicians and philosophers alike.

Reuben Louis Goodstein (1912-1985) foi aluno de Wittgenstein em Cambridge de1931 a 1934. Neste artigo, faço uma breve descrição de seu trabalho na lógica matemática,no qual se percebe a influência das idéias de Wittgenstein, inclusive a substituição,em seu cálculo equacional, da indução matemática por uma regra de unicidade de umafunção definida por uma função recursiva. Esse último aspecto se encontra no Big Typescriptde Wittgenstein. Também mostro que as idéias fundamentais do cálculo equacionalpodem ser encontradas não apenas no período intermediário, mas, in nuce, nas observaçõessobre matemática do Tractatus Logico-philosophicus. A partir disso, procuro desenvolverum argumento contra uma leitura corrente daquele livro, o assim chamado “NovoWittgenstein”. Outra conexão entre Goodstein e Wittgenstein se encontra na rejeição dateoria da quantificação; na parte final do artigo, recorro às observações críticas de Goodsteinsobre a Lei do Terceiro Excluído (que também incluem uma crítica a Brouwer e à suarejeição “pela metade” dessa lei) para lançar luz sobre as observações do próprioWittgenstein a esse respeito.

It is first argued that dialectic was a form of regimented debate, which grew out of public debates in Ancient Greece. A set of rules for dialectical bouts is then given and their meaning explained. The transition from oral to written arguments is briefly examined, leading to the formulation of a delimitation problem in Plato’s dialogues, as he inserted dialectical arguments within ordinary dialogue contexts, turning them into discussions where one of the participants reasons hypothetically to make the other realize that they are not entitled to their view. Doing so, Plato adjusted dialectic to a variety of dialogue purposes and in order to explore this variety, a study of the early tradition of classifying Plato’s dialogues in terms of their ‘character’ is suggested, the results of which are then compared with types of dialogues in contemporary Argumentation Theory.

In 1956, a series of BBC radio talks was published in London under the title The Revolution in Philosophy . This short book included papers by prominent British philosophers of the day, such as Sir Alfred Ayer and Sir Peter Strawson, with an introduction by Gilbert Ryle. Although there is precious little in it concerning the precise nature of the ‘revolution’ alluded to in the title, it is quite clear that these lectures were meant to celebrate in an insular manner the birth of ‘analytic philosophy’ at the hands of Moore, Russell, and Wittgenstein. The use of the word ‘revolution’ to describe the birth of ‘analytical philosophy’ and its rise to near complete dominance in the British universities thus carries with it connotations of a forcible substitution of one philosophical order by a new one that itself owed nothing to the past. To me, however, this talk of ‘revolution’ carries with it a false view of the history of British philosophy: it isn’t ‘historical’ at all, just ideological; it was introduced for a strategic purpose, namely that of encouraging new generations of students to avoid reading the work of earlier philosophers or becoming interested in the problems that concerned them. I shall sketch the broad outlines of a landscape that involves, when limited to the specific topic of the theory of knowledge, no radical break, where no entirely new order replaces an older one: the options, so to speak, and even some of the arguments are the same before and after the soi-disant ‘revolution’

L’opinion est souvent exprimée que Bradley fut un des tout premiers critiques du psychologisme. Dans cet article, j’examine cette thèse en me penchant principalement sur ses Principles of Logic . Je définis le psychologisme au sens étroit comme une thèse portant sur les fondements de la logique, et le psychologisme au sens large comme une thèse plus générale en théorie de la connaissance pour montrer que Bradley a rejeté les deux, même s’il n’avait pas grand chose à dire sur la version étroite. Sa critique de l’autre version est basée sur une distinction entre contenu psychologique et contenu logique, et sur sa défense de la thèse de l’idéalité du contenu logique, avant Frege et Husserl. Cependant, il tient encore à l’idée que le contenu logique provient de la perception. Après une brève présentation de ses critiques de la psychologie associationniste, je montre qu’il fait face à de véritables difficultés en essayant d’éviter de retomber dans le psychologisme en faisant appel à la distinction entre universel abstrait et universel concret. Je termine avec quelques remarques sur la place de Bradley dans l’histoire de la psychologie britannique.One often hears the opinion voiced that Bradley was an early critique of psychologism. In this paper, I investigate that claim, focussing on his Principles of Logic . I define psychologism in the narrow sense as a thesis pertaining to the foundations of logic, and psychologism in the wide sense as a more general thesis concerning the theory of knowledge, and show that Bradley rejected both, although he had little to say on the narrow version. His criticism of the wider version is based on his distinguishing between psychological and logical content and on his defence of the ideality of logical content, before Frege and Husserl. Nevertheless, he still hung to the idea that the latter harks back to ordinary perception. I then review briefly his criticisms of associationism in psychology, to show that he faced some difficulties in trying to avoid lapsing back into psychologism, with an appeal to a distinction between abstract and concrete universals. I conclude with some remarks on the palace of Bradley in the history of British psychology

This volume is a collation of original contributions from the key actors of a new trend in the contemporary theory of knowledge and belief, that we call “dynamic epistemology”. It brings the works of these researchers under a single umbrella by highlighting the coherence of their current themes, and by establishing connections between topics that, up until now, have been investigated independently. It also illustrates how the new analytical toolbox unveils questions about the theory of knowledge, belief, preference, action, and rationality, in a number of central axes in dynamic epistemology: temporal, social, probabilistic and even deontic dynamics.

We will discuss a mathematical proof found in Wittgenstein’s Nachlass, a constructive version of Euler’s proof of the infinity of prime numbers. Although it does not amount to much, this proof allows us to see that Wittgenstein had at least some mathematical skills. At the very last, the proof shows that Wittgenstein was concerned with mathematical practice and it also gives further evidence in support of the claim that, after all, he held a constructivist stance, at least during the transitional period of his thought (1929-33).

L’idéalisme britannique est un mouvement qui a dominé les universités britanniques pendant une cinquantaine d’années à la fin du xixe siècle et au début du xxe siècle, mais qui est passé presque totalement inaperçu dans le monde francophone. Rejetés en bloc par les philosophes analytiques, ces auteurs ont aussi été ignorés pendant longtemps dans leur pays, mais certains d’entre eux, notamment Bradley et Collingwood, jouissent d’un regain d’intérêt à la faveur d’un renouveau des études sur les origines de la philosophie analytique. Ce texte est une introduction à l’idéalisme britannique, qui retrace, dans une première partie plus historique, les grandes lignes de sa genèse, son développement et son déclin. Dans une deuxième partie, nous donnons quelques arguments en faveur d’une étude plus approfondie de ce mouvement.British Idealism is a philosophical movement that dominated British universities , for fifty years around the turn from the XIXth to the XXth century, but it went largely unnoticed in the French-speaking world. Condemned by analytic philosophers, these authors were also ignored in their own country, but some of them, notably Bradley and Collingwood, are now enjoying a newly found popularity within the larger trend towards a study of the origins of analytic philosophy. This text is an introduction to British Idealism that plots, in an historical first part, the outlines of its rise, development and decline. In the second part, we provide reasons for further studies of this movement

John Cook Wilson (1849–1915) was Wykeham Professor of Logic at New College, Oxford and the founder of ‘Oxford Realism’, a philosophical movement that flourished at Oxford during the first decades of the 20th century. Although trained as a classicist and a mathematician, his most important contribution was to the theory of knowledge, where he argued that knowledge is factive and not definable in terms of belief, and he criticized ‘hybrid’ and ‘externalist’ accounts. He also argued for direct realism in perception, criticizing both empiricism and idealism, and argued for a moderate nominalist view of universals as being in rebus and only ‘apprehended’ by their particulars. His influence helped swaying Oxford away from idealism and, through figures such as H. A. Prichard, Gilbert Ryle, or J. L. Austin, his ideas were also to some extent at the origin of ‘moral intuitionism’ and ‘ordinary language philosophy’ which defined much of Oxford philosophy until the second half of the twentieth-century. Nevertheless, his name and legacy were all but forgotten for generations after World War II. Still, his views on knowledge are with us today, being in part at work in the writings of philosophers as diverse as John McDowell, Charles Travis, and Timothy Williamson