The years between 1870 and 1914 saw the emergence of international socialism as a force in European and, to a lesser extent, North American politics. Most notably in Germany, socialist parties began to attract significant blocs of votes. Their broader aspiration to become the agency of a global social transformation was reflected in the formation of the Second International in 1889. Plainly such aspirations required theoretical articulation, and thanks to the influence in particular of the German Social Democratic Party (SPD), Marxism became the most important socialist ideology (though its position never went unchallenged). Indeed, Marxism’s transformation from the doctrine of a handful of German exiles in London into the ideology of a mass movement was largely the work of the SPD. Engels’s key work of popularisation, Anti-Dühring (Marx and Engels 1975–98: XXV), was originally serialised in the SPD paper Vorwärts in 1877–8. The task of simplifying the complexities of Marx’s concepts was later taken on by Kautsky as editor of the Social Democratic weekly Neue Zeit. His voluminous writings provided the way into Marxism for a generation of socialist militants, not merely in Germany but elsewhere in Europe.

MARX VS. BAKUNIN

The Marxism that was thus popularised itself gained sharper definition thanks to the emerging contrast between it and a rival radical ideology, anarchism. The contest between the followers of Marx and Bakunin helped to destroy the First International in the early 1870s. The respective movements which arose from this dispute – social democracy (as, following the example of the SPD, Marxists tended to call their parties) and anarchism – competed for influence in many countries, with Bakunin’s followers often gaining the upper hand in Southern Europe.

Adorno, Theodor (1903–69). Born in Frankfurt, Adorno was precocious intellectually and musically, writing a dissertation on Edmund Husserl at twenty-one and then studying with the Arnold Schoenberg circle in Vienna. Returning to Frankfurt in 1927, he began his lifelong collaboration with Max Horkheimer’s Institute and, in 1931, began teaching at the university. After the Nazi seizure of power, he first lived in London, then joined Horkheimer in New York in 1938. Throughout the 1930s and 1940s, he did important studies in social psychology and in the sociology of music and culture. With Horkheimer, he wrote the Dialectic of Enlightenment (1947) and then, after returning to Frankfurt in 1949, composed his own major works, Negative Dialectics (1966) and Aesthetic Theory (1970). Important studies of him include Buck-Morss, S. (1977), The Origin of Negative Dialecties: Theodor W. Adorno Walter Benjamin, and the Frankfurt Institute (New York: Free Press); Jay, M. (1984), Adorno (Cambridge, MA: Harvard University Press); and Rose, G. (1978). The Melancholy Science: An Introduction to the Thought of W. Adorno (New York: Columbia Press).

Ajdukiewicz, Kazimierz (1890–1963). Ajdukiewicz studied in Lvov with Twardowski, gaining his PhD in 1913 and his Habilitation in 1920. He was an associate professor in Lvov from 1921 to 1926, a professor in Warsaw from 1926 to 1928, in Lvov from 1928 to 1939, in Poznan from 1945 to 1952, and finally once more in Warsaw from 1952 to 1963. His main writings (available in English) are Pragmatic Logic (Warsaw: Polish Scientific Publishers and Dordrecht: Reidel, 1974) and The Scientific World-Perspective and Other Essays, 1931–1963, ed. J. Giedymin (Dordrecht: Reidel).

The German philosopher Martin Heidegger (1889–1976) is by a wide margin the single most influential philosopher of the twentieth century. His original motivation for doing philosophy arose out of religious concerns (he was raised as a Roman Catholic and studied for the priesthood, before converting to a radical form of Lutheranism just after the First World War), and one of the easiest ways to try to make sense of much of his philosophy is to trace in it the shadow of various traditional religious beliefs and doctrines. Thus philosophically in parallel to Heidegger’s own conversion from Catholicism to Protestantism, his early interest in scholastic metaphysics was increasingly placed in the service of a project that had its origins in a certain radical Protestant tradition of ‘negative theology’. The negative theologian holds that God is so different from anything else, so ‘transcendent’, that it is utterly impossible to grasp him in conceptual terms; he is accessible only through faith. Since human reason cannot know him, any form of theology (of rational, conceptually articulated doctrine) can be no more than a perverting distortion of the vital reality of religious belief. The only task left for philosophy in this construction is to destroy theology totally, to undermine from within the pretensions of human reason. Heidegger’s philosophy, like the National Socialism he espoused in the 1930s, was intended to initiate a conservative revolution, which would consign the whole of traditional philosophy, especially Neo-Kantianism, to the rubbish-bin, and also in some not easily definable way transform human life. His religious commitments after the National Socialist period seem to have remained strong until the very end of his life, although they became difficult to categorise in any conventional terms. Thus in an interview given in old age and published by his own request only after his death, he famously remarked that the modern world was so debased that ‘only a God could save us’.

Following the catastrophe of the First World War, philosophical critics on both left and right posed their challenges to liberal-democratic politics in terms of a crisis of civilisation. The First World War had ushered out the last vestiges of Europe’s old regime; no one imagined a new Metternich-legitimist restoration. But what might be the ‘new regime’ of modernity that could resolve the crisis? The answer depended in part upon one’s national vantage-point. The focus here will be on the central and southern European contexts where communist revolutions were launched in 1919–20 only to be supplanted by fascist reactions thereafter. In France, the political outcomes were different but the intellectual environment, similar. Only in Britain and the United States did bourgeois institutions appear largely unchallenged.

While even partisans of liberal democracy understood that ‘rescuing bourgeois Europe meant recasting bourgeois Europe’ (Maier 1975: 594), its critics sought to sweep it aside in a bold revolutionary stroke. For them, fin-de-siècle fears that a looming mass society would become a quantitative, materialist nightmare had been borne out, necessitating a turn to radical solutions. A radical conservatism demanding new institutions to restore old values came into full flower, particularly in Germany, where the fears had run deepest, while Marxists, emboldened by the Bolshevik triumph in 1917, sought to theorise the nature of, and preconditions for, a new basis of Western civilisation. Both extremes appreciated the raw power of ‘Americanism’ as a principle of social organisation, but despite occasional admirers (like Gramsci), most detested it as an alien invasion.

INTRODUCTION

In the most narrow sense, the Polish school of logic may be understood, as the Warsaw school of mathematical logic with Jan Łukasiewicz, Stanisław Leśniewski, and Alfred Tarski as the leading figures. However, valuable contributions to mathematical logic were also made outside Warsaw, in particular by Leon Chwistek. Thus, the Polish school of logic sensu largo also comprises logicians not belonging to the Warsaw school of logic. The third interpretation is still broader. If logic is not restricted only to mathematical logic, several Polish philosophers who were strongly influenced by formal logical results, for example Kazimierz Ajdukiewicz and Tadeusz Kotarbiński, can be included in the Polish school of logic sensu largissimo. Polish work on logic can therefore encompass a variety of topics, from the ‘hard’ foundations of mathematics (e.g. inaccessible cardinals, the structure of the real line, or equivalents of the axiom of choice) through formal logic, semantics, and philosophy of science to ideas in ontology and epistemology motivated by logic or analysed by its tools. Since the development of logic in Poland is a remarkable historical phenomenon, I shall first discuss its social history, especially the rise of the Warsaw school. Then I shall describe the philosophical views in question, the most important and characteristic formal results of Polish logicians, their research in the history of logic, and applications of logic to philosophy. My discussion will be selective: in particular I will omit most results in the ‘hard’ foundations of mathematics.

The initial empirical corroboration of the General Theory of Relativity (GTR) was announced to the world at a packed joint meeting of the Royal Society of London and the Royal Astronomical Society on 6 November 1919. Lengthy data analysis of solar eclipse observations, made the previous May by a joint British expedition to Brazil and to an island off the coast of West Africa, confirmed that the GTR-predicted amount of ‘bending’ of light rays in the solar gravitational field had indeed been found. Under a portrait of Isaac Newton, J. J. Thompson, president of the Royal Society, pronounced this ‘the most important result obtained in connection with the theory of gravitation since Newton’s day, and … one of the highest achievements of human thought’ (quoted from Pais 1982: 305). There followed the ‘relativity-rumpus’ (Sommerfeld 1949: 101), a public clamour that, regarding a purely scientific theory without apparent military or technological application, was completely unprecedented, and is, as yet, unmatched. Almost overnight, Albert Einstein, hitherto largely unknown outside the rarefied (and by present standards, miniscule) circle of theoretical physicists, became world famous and a favoured target of anti-Semitism.

A plausible explanation of this astonishing spectacle points to the exhausted state of European culture, eager for diversion after the ravages of four years of world war, political revolution, and an influenza pandemic in which millions perished. Diversion the theory certainly provided, with the novelty of claims made on its behalf and its aura of incomprehensibility. But even among the scientifically literate, there was considerable controversy and misunderstanding concerning the theory’s physical content as well as its philosophical implications.

From 1870 to 1945 Spanish philosophy lived moments of splendour which, in contrast with the spiritual stagnation of the two preceding centuries, have earned it the epithet ‘The Silver Age’ of Spanish culture and thought. The great thinkers Unamuno and Ortega can be seen as its culmination. But it would be oversimplifying matters to reduce that splendour to only these two figures. In this chapter I shall consider five major moments: (1) Krausism; (2) Unamuno and the ‘Generation of'98’; (3) Ortega and the ‘Generation of'14’; (4) the Catalan philosopher Eugeni d'Ors; and (5) Zubiri and the ‘Generation of'27’.

KRAUSISM

For political and religious reasons Spanish culture has long kept itself apart from the rest of Europe. This explains why, especially since the Enlightenment, Spanish intellectual circles have raised again and again, with angry protest by traditionalists, the question of the europeización of Spain. Initially, people understood by this an opening up to French influence. But in the middle of the nineteenth century this term acquired a new meaning. The young Spaniard Julián Sanz del Río, who was interested in reforming the thought of his country, travelled to Germany in 1843, contacted there the philosophical circle of the Kantian/Schellingian Christian Krause, and returned home a converted apostle of Krausism, which spread like wildfire along university circles.

The Spanish Krausists embraced enthusiastically the Kantian moral idealism which was so characteristic of Krause himself. In time, nevertheless, this idealism entered into an alliance with the positivist materialism which was also in fashion: the common denominator of the idealist Krausists and materialist positivists was their passion for liberalism and progress.

INTRODUCTION

The great French philosopher-historian of science Emile Meyerson (1859–1933) began his 1929 Encyclopedia Britannica article ‘Explanation’ with the following words:

Meyerson’s conclusion would be difficult to overstate: the structure of any given science — indeed, of science itself — is developed around the ideal of explanation peculiar to it. Explanations in physics differ formally and materially from those in biology; and both differ from explanations provided by geologists and sociologists; even more generally, explanations in science differ widely from those given in, say, law or religion.

MEYERSON ON THE TWO MODES OF EXPLANATION

From the publication of the 1908 first edition (of three) of his monumental Identité et Realité (Identity and Reality) until his death in 1933, Emile Meyerson was not only France’s dominant philosopher of science, he was one of the most important philosophers of science throughout the Western world. In the opening chapter of Identity and Reality, Meyerson speaks of two sharply opposed modes of explanation: the ‘mode of law’, and the ‘mode of cause’. Each mode has ancient philosophical roots. Law-explanations may with some justice be traced to Heraclitus’s dictum that everything changes except the law of change itself. Cause–explanations, according to Meyerson, trace back through atomic theory all the way to Parmenides’s notion of the unchanging self-identity of being.

NEW BEGINNINGS

The 1870s was a decade of new beginnings in British moral philosophy. This was partly in reaction to the work of J. S. Mill, who had dominated the previous decade and whose Utilitarianism had appeared in book form in 1863. First, in 1870, John Grote’s Examination of the Utilitarian Philosophy was posthumously published (Grote had been professor at Cambridge when Mill’s work appeared). Then in 1874, also from Cambridge, came what has justly been called the first work of modern professional moral philosophy, Henry Sidgwick’s Methods of Ethics. Meanwhile an idealist response to Mill (and to empiricist thinking more generally) had been brewing in Oxford, particularly in the lectures of T. H. Green. Its first significant ethical work was F. H. Bradley’s Ethical Studies, published two years after Sidgwick’s in 1876 (whereupon Bradley and Sidgwick promptly fell on each other in critical reviews and pamphlets). At the end of this decade, in 1879, came Herbert Spencer’s Data of Ethics. Although Spencer was more favourable to empirical methods than Sidgwick, Green, or Bradley, and although like Mill and unlike them he worked outside the established universities, he was nevertheless another critic of Mill.

Mill stood for empirical, observational, methods and held that the central ethical issue was between results based on observation of actual human behaviour (which he thought led to his own utilitarianism) and results based upon supposed direct intuitions of moral truths (as believed in by his Cambridge opponent, Whewell). In 1870 the conflict between empiricist utilitarianism and intuitionism seemed to be the central issue, or problem, in ethics. For example W. Lecky’s History of European Morals of 1869 frames its study round the ‘great controversy, springing from the rival claims of intuition and utility’ (Lecky 1869: 1).

The allies portrayed their defeat of Germany in 1918 as the triumph of liberal democracy over authoritarianism, a victory marked by the establishment of the League of Nations and the creation of the Weimar Republic. However, the Russian Revolution, the rise of fascism and the economic depression of the 1930s almost immediately placed liberal democrats on the defensive. Critics argued that mass democracy and the spread of bureaucracy within both the private and public sectors had rendered the liberal ethic of the autonomous individual an anachronism. The corporate manager had replaced the entrepreneur within the economy, and the manipulation of popular opinion by the media and party machines had supplanted rational debate between disinterested individuals in politics. Individual identity and will were shaped by functional, ethnic and cultural group membership rather than innate preferences and capabilities, the exercise of reason, or effort. New social and economic conditions required novel forms of political and industrial organisation that combined decisive and expert leadership with efficient administration, thereby harnessing popular support and energy to the collective good in a manner supposedly unavailable to liberals. The economic crisis was taken as confirming this diagnosis of liberal democracy’s malaise.

The challenge to liberal democracy was threefold, therefore, involving an attack on the contemporary relevance of the market, representative democracy, and the values underlying them. In their various defences against such criticisms, the divisions amongst liberals were often as sharp as (and frequently mirrored) those between them and their opponents. Like the pre-war debates, disagreement centred on the role and nature of the state, the legitimacy and efficacy of its interventions in social life, and the parts played by democracy and leadership within its operations.

PROBABILITY IN NINETEENTH-CENTURY SCIENCE

Variation was considered, well into the second half of the nineteenth century, to be deviation from an ideal value. This is clear in the ‘social physics’ of Adolphe Quetelet, where the ideal was represented by the notion of ‘average man’. In astronomical observation, the model behind this line of thought, there is supposed to be a true value in an observation, from which the actual value deviates through the presence of small erratic causes. In mathematical error theory, one could show that numerous small and mutually independent errors produce the familiar bell-shaped normal curve around a true value. But if observations contain a systematic error, this can be identified and its effect eliminated. All sorts of data regarding society were collected into public state records (whence comes the term statistics), showing remarkable statistical stability from year to year. Such stability, as in criminal records, was explained as the very nearly deterministic result of the sum of a great number of free individual acts (see Krüger et al. 1987 for studies of these developments).

Around 1860, the physicist James Clerk Maxwell theoretically determined a normal Gaussian distribution law for the velocities of gas molecules. This discovery later led to statistical mechanics in the work of Ludwig Boltzmann and Josiah Willard Gibbs. Here there was no true unknown value, but genuine variation not reducible to effects of external errors. The world view of classical physics held that all motions of matter follow the deterministic laws of Newtonian mechanics. It was therefore argued, throughout the second half of the nineteenth century, and well into the twentieth, that there is an inherent contradiction in the foundations of statistical physics.

‘CATHOLIC PHILOSOPHY’?

The words ‘Catholic’ and ‘philosophy’ form an uneasy combination which arguably should not exist at all, since it seems to carry the misleading implication that all the authors to whom it refers had an allegiance to Rome, and reduces to a questionable common denominator a number of thinkers whose views were sometimes conflicting. It is therefore preferable to speak of ‘Catholic philosophers’ in the plural, or, if we still insist on using the expression, to put the epithet between cautious quotation marks: ‘Catholic philosophy’.

One thinker to whom the term ‘Catholic philosophy’ could, in a sense, be applied was Maurice Blondel (1861–1949), despite the fact that, in his anxiety to avoid the accusation that his philosophy was an apologetics, he was careful to point out in a revealingly entitled book Le problème de la Philosophie Catholique (1932) that he had not used this problematical expression ‘one single time’ in his earlier classic work L'Action (1893). Even so he wanted to restore it to its original, etymological, meaning of universality, the full significance of which was indissociable from the ecclesiastical dimension. Thus, in the third part of the work, he endeavoured in twenty pages to demonstrate ‘in what sense, with what reservations, and at what price “Catholic” … philosophy is conceivable and achievable’. This was logically in keeping with his Pan-Christianism, which was stated with supreme self-assurance in La philosophie et l'Esprit chrétien (1944), the fourth part of a ‘tetralogy’ of works written with a common purpose, the other parts being La Pensée (1934), L'Etre et les Etres (1935), and a new volume again entitled L'Action (1936–7).

OVERVIEW

Modern symbolic logic, including axiomatic set theory, developed out of the works of Boole, Peirce, Cantor, and Frege in the nineteenth century. The contours of the subject as it is known today, however, were largely established in the decade between 1928 and 1938. During those years the scope of the discipline was expanded, both through clarification of the distinction between syntax and semantics and through recognition of different logical systems, in contrast to the conception of logic as a universal system within which all reasoning must be carried out. At the same time the primary focus of logical investigation was narrowed to the study of first-order logic (then called the ‘restricted functional calculus’), in which quantification is allowed only over the elements of an underlying structure, not over subsets thereof. The former development made possible the formulation and resolution of metasystematic questions, such as the consistency or completeness of axiomatic theories, while the latte, by isolating a more tractable logical framework, facilitated the derivation of theorems. Both developments led to the study of model-theoretic issues, such as the compactness of logical systems and the existence of non-isomorphic models of arithmetic and set theory.

In addition, questions concerning definability and decidability by axiomatic or algorithmic means were given precise mathematical formulations through the definition of the class of recursive functions and the enunciation of Church’s Thesis (that the recursive functions are exactly those intuitively characterised as being effectively computable). Formal proofs of indefinability and undecidability theorems thereby became possible, with profound implications for Hilbert’s proof theory and for the subsequent development of computer science.

INTRODUCTION

Among the most important events of twentieth-century physics, we must surely count the development of the special and the general theories of relativity by Einstein in 1905 and 1916, and that of quantum mechanics, which was worked out about ten years later by Bohr, Heisenberg, Schrödinger, and de Broglie. Owing to these theories, the physicist’s conception of space-time underwent two major upheavals.

Although they apply on different scales, the general theory of relativity and the quantum field theory play a fundamental role in describing the natural world, so a complete description of nature must encompass both of them. The formal attempt to quantise general relativity, however, leads to nonsensical infinite formulas. In the sixties non-Abelian gauge theory emerged as a framework for describing all natural forces except gravity; however, at the same time, the inconsistency between general relativity and quantum field theory emerged clearly as the limitation of twentieth-century physics. The resulting problem is a theorists’ problem par excellence: experiments provide little help, and the inconsistency illustrates the intermingling of philosophical, mathematical, and physical thought.

It is a fact of great significance that every physical theory of some generality and scope, whether it is a classical or a quantum theory, a particle or a field theory, presupposes a space-time geometry for the formulation of its laws and for its interpretation, and the choice of this geometry predetermines to some extent the laws which are taken to govern the behaviour of matter. Thus Newton’s classical mechanics (and especially its law of gravitation) is based on the assumption of an absolute simultaneity relation between events and a Euclidean geometry; similarly, the physical principle of the universal proportionality of inertial and gravitational mass, as recognised by Einstein between 1907 and 1915, requires the assignment of a non-integrable, that is, path-dependent, linear connection with non-vanishing curvature to space-time (the law of parallel displacement).