Philosophy and Ideology. Z. A. Jordan 1963


The beginning of modern philosophy in Poland can be given a precise date. It was in 1895 that Kazimierz Twardowski (1866-1938) was appointed to the chair of philosophy at Lwów University and became the founder of modern Polish philosophy[2].

Twardowski belonged to the so-called Austrian school whose head was Franz Brentano. The large circle of Brentanists included psychologists and philosophers of a world-wide reputation: Alexius Meinong, Alois Höfler, Oskar Kraus, Christian Ehrenfels, Carl Stumpf. Twardowski’s contributions to the teaching of the school considered to be the most important are contained in his book Zur Lehre vum Inhalt und Gegenstand der Vorstellungen. Eine psychologische Untersuchung, published in 1894. They provided a link in the development of thought which, on the one side, led from Brentano’s descriptive psychology to Meinong ontology (Gegenstandstheorie), and to Husserl’s phenomenology, on the other. Husserl recognised the importance of Twardowski contribution and, after the publication of Logische Untersuchungen, Twardowski’s reputation was established in Austrian and German philosophy[3].

When Twardowski arrived in Lwów, he came to a philosophical wilderness. There was much interest in philosophy, but it was taught and pursued in the traditional, somewhat amateurish manner. Twardowski clearly faced the choice of either continuing his own work and returning to Vienna as soon as possible, or staying in Lwów, giving up his own studies, and devoting his life to teaching. He decided upon the latter course. This decision must have been a momentous one for him. If constituted the decisive turning point in the history of philosophy in Poland.

Twardowski’s teaching was based on Brentano’s philosophy and on its further development, to which other Brentanists and himself contributed. In a certain sense Brentano was a supporter of psychologism; he saw in psychology the basic science of all science. Psychology, as he conceived it, was an empirical discipline, although its empiricism was not of the kind familiar to natural scientists. It did not make any use of experiments and very little of observation; it did not try to reduce psychological phenomena to physiological processes, as was done by G. T. Fechner and W. M. Wundt. Moreover, Brentano agreed with Comte that psychological phenomena cannot be really observed by introspection. Instead, we can directly apprehend them and, by a careful and minute description of what there is before our mind, acquire the knowledge of the phenomena involved. Brentano’s psychology is a descriptive science, based on direct apprehension of its subject matter and thus superior, in his opinion, to natural science, which is barred from direct access to what it investigates. In this sense, psychology provides fundamental knowledge for all science. Brentano returned to the thesis of the French rationalist thinkers of the seventeenth century that we know the mind better than we shall ever know matter.

Brentano’s descriptive psychology provides a basis for a general method of philosophical investigations. When we perceive a tree outside the window, we cannot be aware of its being there without being aware at the same time of the act of seeing it. This distinction between an act and its object, which although distinct are never given separately and might thus be confused, is fundamental for Brentano’s philosophy. Only the act of a representation – and by this term Brentano refers to anything that is apprehended by or is before the mind – constitutes a psychological phenomenon. The object of an act is often a physical thing and cannot be, therefore, a constituent of a mental phenomenon.

Besides the act and object, there is still a third element, which must be distinguished in every mental phenomenon – the content of the act. Brentano did not keep the object and the content of the act clearly apart and the sharp distinction between them is Twardowski’s important contribution. The content of the act is the latter’s ‘quality’, by virtue of which the act is directed towards its object and not to something else, as well as that by which it presents the object to the mind in one manner rather than another. To this distinction between content and object Twardowski added two further theses. First, that to every representation there corresponds an object and, second, that there is a necessary relation between a representation and its object. The latter thesis, which for Twardowski was a psychological statement, might have ultimately paved the way for Husserl’s transcendental idealism.

Brentano’s conception of mental phenomena contained the nucleus of ideas that led far beyond his initial point of departure. They could lead in the direction which Husserl took, or to conceptual analysis and formal logic, to logical analysis of language, to syntax and semantics. The choice of roads depended on what was given paramount attention: the descriptive psychology which dealt with the mental act and its content, or the objects apprehended in the act of representation. This duality in Brentano’s initial position became more pronounced owing to Twardowski’s distinction. Twardowski took the second course and made extensive excursions, beyond the bounds of descriptive psychology, into the field of logic and the theory of knowledge.

In Poland Brentano’s philosophy was thus given a distinctly realistic orientation. While his descriptive psychology provided the means for specifically psychological investigations, carried on by Twardowski himself and by a large number of his pupils, it also constituted a starting point for a wide range of epistemological and ontological research, which undermined and finally destroyed the last vestiges of psychologism, in the above-defined sense, common to Brentano and Twardowski.

Only the acts are immanent to and constituents of the consciousness; the objects, given by means of representations, are outside the consciousness and transcendent to it. The analysis of psychological phenomena, carried by means of descriptive psychology, revealed a whole realm of objects independent from the experiencing subject – of things, meanings, concepts, logical laws, which are neither immanent to the mind nor mere genemlisations of the mind’s activity. To describe these objects, to differentiate between them, to reveal their structure and relations, became the proper task of philosophy. They are found by the mind, and psychology only helps to establish their reality empirically. Twardowski’s writings abound in suggestive psychological descriptions and thorough philosophical analysis, in clarifications and definitions of the philosophical conceptual framework used in the discussion of the questions of psychology, logic and the theory of knowledge (the different kinds of representations, concepts, judgements, sentences, propositions, and the notion of truth). This move forward, away from psychologism, is unmistakable and pronounced in the whole activity of Twardowski. He laid the foundations for the logical conception of science and for epistemology in the etymological sense of this term. Twardowski called his method by a name now very familiar – the analytical method[4].

In his lectures, Twardowski dealt approvingly with the reform of formal logic, initiated at that time, paid much attention to logic and encouraged his pupils to do so. But in an article widely read in Poland at that time, he pronounced himself against the ‘symbolomania’ in which one of his pupils (Jan Łukasiewicz – unnamed in the article) indulged, so Twardowski thought, too much. Łukasiewicz not only agreed with his teacher that logic had been led astray by psychologism, but was also convinced that it was exact logical analysis that should replace psychological examinations of the origin of concepts as the method of philosophical investigations. Twardowski rejected this suggestion. Logic is not a self-sufficient, autonomous discipline. It is, rather, an instrument to be carefully used for the solution of definite problems. Its concepts cannot be assumed; they must be critically examined and applied in accordance with the results of philosophical analysis. This was the attitude which Husserl took with respect to modern formal logic and to logical investigations on the foundations of mathematics, and which was represented by Roman Ingarden in Poland in the ‘thirties. Twardowski’s views also influenced Stanislaw Leśniewski, who had begun his studies under Hans Cornelius in Germany, but completed them in Lwów. It perhaps explains Leśniewski’s initial distrust of formalism which he later abandoned when he found a way of his own to combine Twardowski’s standpoint with formal techniques.

However much Twardowski might have been opposed to the traditional philosophy in Poland and abroad – its lack of a method, its terminological confusions and conceptual ambiguities, its failure to find ‘empirical’ foundations – he was no admirer of scientism. He believed that philosophy could work out a method of its own, appropriate to its subject matter and fully satisfying the requirements of scientific procedure. Philosophy was to him an autonomous science and not a discipline to be made scientific by parcelling out its various problems to particular sciences. He was only a severe critic of the traditional philosophy, and not its liquidator. He was ready to undertake work of reform, and he practised it throughout his life. But his programme was limited and did not include the drastic measures which his former pupils were later to advocate.

The direction in which Twardowski led his followers in Poland required them to undertake painstaking analysis of specific problems which were rich in conceptual and terminological distinctions, and directed rather to the clarification than to the solution of the problems involved. Philosophy, as he conceived and taught it, was unlike its popular conception, impressed upon the popular mind by Poland’s romantic poets and messianic philosophers, who more or less identified it with flights of imagination and poetical inspiration. Philosophy became a pedestrian affair, an elaborate and highly specialised technique of thinking, which, being closer than ever before to the hard ground of everyday experience and common sense, could not be followed, as was the case in the past, by educated but philosophically untrained amateurs. A sharp line of division emerged between the old and poetic and the new and scientific philosophy, the division line being concerned rather with the standards of performance than the subject-matter of what was considered to be a philosopher’s proper study. Twardowski’s school, wrote Tadeusz Czeżowski, was a hard one. It made great demands on the beginner and at first offered little reward[5].

What is known under the name of the Lwów school had thus little in common with a philosophical school of thought; it was a school of philosophical method and thinking. Its members were not linked with each other and with their teacher by a common body of philosophical assumptions and beliefs; they differed widely in this respect. The unity was forged by the common formal standards of clear thinking, precision of conceptual analysis, and by the terminological distinctions and mode of expression.

Twardowski did not proclaim these standards, but practised them himself in his lectures and seminars which covered a great variety of subjects – psychology, logic, history of philosophy, ethics – and thus showed that the method advocated by him admitted of universal application. He sharply differentiated between what can be accepted as a body of philosophical knowledge – the various problems, their different solutions, the arguments for and against them, the basic philosophical trends and schools of thought – and the Weltanschauung, the world outlook, which goes beyond what can be known and which accepts certain tentative solutions as final on the basis of global value judgements. He did not reject them altogether, recognising their practical utility, at the same time denying them scientific value. Twardowski’s vast knowledge of classical philosophical literature made him abhor all onesidedness born of ignorance or contempt for the achievements of the past and excessive claims of being in possession of the whole truth[6].

The secret of Twardowski’s influence and achievement as a teacher lay not only in the power of his mind, his vast and varied knowledge, his didactic talents and efficiency, but also in the Socratic quality of his personality, to which all his pupils testify unanimously. There was an atmosphere of uncompromising integrity about him. His demands for precision and exactitude in philosophical thinking which he practised himself and inculcated in others, sprang from his deep sense of intellectual honesty, and were a reflection of his unremittent concern and respect for truth. To choose a philosopher’s life was to him to follow an exacting calling which demanded an effort both of mind and will.

Twardowski taught as much by example as by his lectures and seminars. He left an inheritance which is not measurable in purely intellectual values, an invisible power which once created pervades the minds of those who have been affected by it and who in turn pass it on multiplied to the others.

Finally, Twardowski was the organiser of philosophical activities in Poland. He devised and tried out the university curriculum and didactic methods of teaching philosophy, which, with minor changes, have been followed ever since. He organised the first psychological laboratory in Poland (1901) and set up in Lwów the first Philosophical Society (1904). He actively supported the decision to start the first Polish philosophical periodical, Przegląd Filozoficzny founded by Władysław We ryho in Warsaw in 1898, and he founded in 1911 and edited until his death Ruch Filozoficzny, a bibliographical philosophical publication unique of its kind at that time, which kept Polish philosophers informed about philosophical developments at home and abroad. He initiated the translation into Polish of classical philosophical literature and encouraged others to follow his example.

When Twardowski died in 1938, his life work as founder of the school, as teacher and organiser of philosophical activities, had already brought ample results. The philosophical scene in Poland was completely transformed and philosophy flourished. Philosophy became an academic, scientific discipline, taught by his former pupils, at all the Polish universities. The philosophical activities were well organised. There were national philosophical congresses every few years, (the first was held in 1923), philosophical societies meeting regularly in every university centre, and four philosophical periodicals of a high standard were published. There was above all a thriving school of philosophical thinking, vigorous and confident, with an established reputation for its various achievements. The memory of Twardowski was a living force and the record of his achievements an inspiration for further sustained work by all. It was widely felt that Twardowski found the best way to combine abstract pursuit and search for truth with service to the community, or, to use the fashionable expression of the post-war period, he found how science can best serve life.

Twardowski had numerous pupils and followers displaying a wide range of abilities and interests. Between the oldest and youngest among them there was an age difference of more than a generation. Jan Łukasiewicz (1878-1956) and Władysław Witwicki (1878-1948) were Twardowski’s oldest pupils. The first excelled in abstract reasoning, the second, a leading Polish psychologist and Plato’s masterful translator, displayed a great power of observation and was unsurpassed in subtle and detailed descriptions of psychic phenomena, especially of emotions. The fact that these two men, so different in what they strived for and achieved, came from the same school is telling evidence of Twardowski’s breadth of mind and tolerance.

To the same generation as Łukasiewicz and Witwicki belong Kazimierz Ajdukiewicz (born 1890), Stefan Baley (1885-1952), Stefan Błachowski (born 1889), Władysław Borowski (1879-1938), Tadeusz Czeżowski (born 1889), Daniela Gromska, Salomon Igel (1889-1942), Stanisław Kaczorowski (born 1889), Tadeusz Kotarbiński (born 1886), Mieczysław Kreutz (born 1892), Stanisław Leśniewski (1886-1939), Kazimierz Sośnicki (born 1883) and Zygmunt Zawirski (1882-1948). But besides these thinkers, who later became prominent in psychology, formal logic and philosophy, there were also others who were either Twardowski’s pupils or came under his influence, though their main interest lay outside philosophy. Among them were Ryszard Gansiniec (1888-1958), a classical scholar, Julian Kleiner (1886-1957), a historian of literature, Zygmunt Łempicki (1886-1943), a German philologist and historian of culture of many accomplishments, Ostap Ortwin (1873-1942), a literary critic, Władysław Szumowski (1875-1954), the holder of the first chair of history and philosophy of medicine at the University of Cracow[7], Bogdan Nawroczyński (born 1882), a professor of pedagogy, and Mieczysław Treter (1883-1944), an art historian and theorist.

The second generation of Twardowski’s pupils included Walter Auerbach, Eugenia Blaustein (1905-1944), Leopold Blaustein (1905-1944), Izydora Dąmbska, Maria Kokoszyńska, Seweryna Łuszczewska-Romahnowa, Henryk Mehlberg, Zygmunt Schmierer, Helena Słoniewska, Tadeusz Witwicki. They took their degrees after the First World War, were taught by Twardowski and Ajdukiewicz, and, with some exceptions, belong to a different philosophical formation known as the Warsaw school.

Until recently Twardowski’s school was referred to, at least in Poland, as the Lwów-Warsaw school. This was an apt description in view of the continuity in the philosophical development and of the persistence of certain characteristic traits in the philosophical method that have been apparent from the time Twardowski came to Lwów up to the present day. This continuity, which both its supporters and opponents rightly and strongly emphasise[8], is best testified to by the fact that all or practically all the leaders of the new philosophical orientation that emerged in Poland after the First World War were at some time or other Twardowski’s pupils and followers. The Lwów-Warsaw school was also a convenient name, because it helped to differentiate the philosophical school from the Warsaw school of mathematicians, led by Zygmunt Janiszewski (1888-1920), Wacław Sierpiński (born 1882), Kazimierz Kuratowski (born 1896) and Stefan Mazurkiewicz (1888-1945), which shortly after the First World War acquired a world-wide reputation, as well as from the Warsaw school of logic, whose undisputed leaders were Leśniewski, Łukasiewicz and Alfred Tarski. Both the mathematical and the logical school were often called, particularly abroad, ‘the Warsaw school’ without any further qualification.

There is no doubt, however, that Twardowski’s conception of philosophy, which he imparted to his pupils and which they at first espoused, differed in many and important respects from that which they evolved in their maturity. The differences are real, deep, and sometimes fundamental, and the passage of time put into relief what in the past was only vaguely seen and understood. Kotarbiński, one of the protagonists in the development of ideas originated by Twardowski, rightly emphasised that it is more correct to speak of the Lwów (Twardowski’s) and the Warsaw school than to class them together[9].

To put it concisely, the Lwów school can be described as a period of psychologism and the Warsaw school as that of ‘logicism’. By psychologism in this context should not be understood the well known historical trend which tried to reduce philosophy to psychology, the laws of logic or sociology to psychological laws, and historical and cultural events to the state of consciousness of the contemplating mind. As it was indicated above, psychologism stands here for the opinion that whatever is studied by any science must be first given in the representation (in Brentano’s sense) and the examination of what is given is the task of psychology.

The pupils who remained most faithful to their teacher and who could still be described as members of Twardowski’s school when the Warsaw school came into being, were those whose interests were psychological. Some of them, like Blachowski and Baley, became experimental psychologists; they extended the scope, but adhered to Twardowski’s teaching in letter and spirit[10]. Others, and these included perhaps the most original psychologists among Twardowski’s followers, contributed to the expansion of descriptive psychology and to the improvement of the methodology of psychology in general. To this group belonged Władysław Witwicki, Igel, Kreutz, and, among the younger, Auerbach and Blaustein, whose life of great promise and high achievements was cut short at an early age in a concentration camp.

Those of Twardowski’s pupils who were interested in philosophy followed a path of their own rather than deviating from the road paved by him. Their method was continuation of, but it also differed from, Twardowski’s approach both in manner and content. Philosophy in Poland took its now familiar modern form only in the Warsaw school.

If attention is concentrated on the differences, the contrast between the Lwów and Warsaw schools is considerable. They can be differentiated in a fourfold way. The Lwów school represented the pre-logistic stage of development; it showed little, if any, interest in the logical examination of the foundations, structure and methods of the empirical and deductive sciences, (psychology being perhaps the only exception to this rule); it did not attempt to solve any major philosophical problem being content with the preparatory work, with forging a conceptual apparatus and a philosophical vocabulary; and it recognised the existence of a philosophical method irreducible to those of the deductive and empirical sciences.

In contrast to it, the Warsaw school devoted most of its energy to modern formal logic and its applications; showed a lively and unflagging interest in methodology and theory of the deductive and empirical sciences; took up in a modern form some traditional major philosophical questions, in particular in ontology and the theory of knowledge, and tried to solve them with the aid of methods derived from formal logic and the philosophy of language (logical syntax and semantics); and, finally, it denied the existence of an autonomous philosophical method, coming very close to scientism.

Scientism is not used here as term of opprobrium to denote a misguided, if not a straightforwardly naive effort, to imitate in philosophy the language and methods of science. It refers to the philosophical trend, which proclaimed that most, if not all, philosophical problems have a sound core and misleading adjuncts. Furthermore, it believed that if the latter are discarded and the former are either reformulated and re-examined by means of logical methods or handed over to an appropriate science, the philosophical perplexities could be resolved once and for all. Philosophy has no other methods of inquiry but those which are either empirical or deductive (in the technical sense of these terms). Problems which cannot be either clearly stated or investigated by the methods of science lie outside the scope of scientific philosophy. Scientism of the Warsaw school was a methodological and philosophically neutral doctrine. It relied on the methods of science, since only these methods provide warranted knowledge.

Nothing better exemplifies the differences between the Lwów and the Warsaw school than the contrast between the writings of Leśniewski and Łukasiewicz published at the time when they were still Twardowski’s followers and those which made them famous at a later period. In the years 1911-1914 Leśniewski contributed four articles to Przegląd Filozoficzny, all of them dealing with logical problems. They were examined informally with thoroughness and minuteness, which still deserve high admiration. One of them dealt with Russell’s antinomy and solved it by means of what later became known as Leśniewski’s theory of semantical categories (theory of types). What is striking in these articles from the present point of view, however, is the absence of symbolism and formal techniques. They were not used at all by a thinker who even among the logicians acquired the reputation of pushing formalism to its extreme and who almost ceased to use ordinary speech when he expounded his logical constructions. These articles were later repudiated by Leśniewski who expressed his regret that such immature contributions, unequal to the problems involved, should ever have been published[11].

łukasiewicz’s development was not less striking. He was appointed lecturer in philosophy at Lwów University in 1906 and moved to Warsaw in 1915, where he taught logic until the outbreak of the Second World War. Practically all his important work was done in Warsaw[12].

łukasiewicz’s first papers, published in Przegląd Filozoficzny (1903, 1907), dealt with the problems of induction and with the notion of cause. Notes and reviews, which he wrote at that time, show the interest with which he followed the criticism of psychologism in logic launched by Husserl, Meinong and Höfler. His first major publication was On the Principle of Contradiction in Aristotle, followed three years later by Die logischen Grundlagen der Wahrscheinlichkeitsrechnung. This period might be considered closed with two essays – On Science and The Concept of Magnitude[13].

Philosophically his most important contributions of that period were probably On the Principle of Contradiction in Aristotle and On Science. The latter was twice reprinted twenty years later and its description and classification of different kinds of reasoning were until recently universally accepted in Poland[14]. The former is a historical and systematic study of the principle of non-contradiction in Aristotle, still of a considerable value for a historian of logic, in which with an exemplary clarity the distinction between the ontological, logical and sychological principles of non-contradiction was made and their respective validity discussed. This distinction has also turned out to be of permanent value and has provided the basis from which every discussion – and they became frequent in recent years in Poland – on the status of the principle of noncontradiction used to start. The ontological and the logical principles of noncontradiction are equivalent, but neither of them is equivalent to the psychological principle. The latter states that two beliefs expressed in contradictory sentences cannot exist in one mind. It is clear that this statement is an empirical probability law and not a principle at all.

łukasiewicz rejected the claim that the principle of non-contradiction in its ontological or logical formulation is a ‘first principle’ or, as it was put at that time, a ‘fundamental law of thought’. It is a logical theorem, whose validity may be doubted. It must be proved, therefore, but such a proof cannot be found either in Aristotle or anywhere else. If the principle of non-contradiction is neither a ‘first principle’ nor a proved theorem, we must recognise that we accept it for its important extra-logical reasons, of practical and moral nature, namely as a means to guard us against falsehood and lies[15]. Apart from other reasons, striking at that time, but no longer valid today, by which he supported his opinions, Łukasiewicz used Couturat’s algebra of logic to show that the principle of non-contradiction is a theorem and not an axiom, a theorem provable in this system. It should be added that Łukasiewicz never again returned to the view on the principle of non-contradiction expounded in his first major work. He recognised that the metalogical principle of non-contradiction must be assumed as an absolute principle, if logic and science in generil is to make sense [16].

The study On the Principle of Contradiction in Aristotle is memorable for another reason. It made a reference to the Aristotelian doctrine on contingent propositions, which were to play a considerable role in the discovery of manyvalued logics, mentioned the possibility of constructing a non-Aristotelian logic, and shortly discussed the relation between time and the validity of the principle of non-contradiction with respect to the world of experience. The idea of a nonAristotelian logic took firmer roots in Die logischen Grundlagen der Wahrscheinlichkeitsrechnung, where he came to the conclusion that the principle of bivalence is not absolute. There are sentences which are neither true nor false and to reject them on the ground of Aristotle’s principle of bivalence is to transform that principle into a prejudice[17].

All these contributions contained many original ideas, they excelled in clarity of thought, in precision and simplicity of language. They made Łukasiewicz a rising philosophical star in Poland, but not an explorer of new lands. Philosophically he moved well within the area familiar to Twardowski’s school and he did not deny its assumptions. Before he became completely absorbed in formal logic, he considered that effective philosophical methods for solving philosophical problems could be found. He changed his opinion only with his first logical discoveries, which convinced him of the inventive and explanatory power of formal logic. His demand for the reconstruction of philosophy by means of formal logic probably began emerging in his mind at the same time as the idea of many-valued logics was born, to solve, as he then thought, some of the philosophical problems which haunted him[18] and to prompt further discoveries in formal logic. This opened a new period in the development of philosophy in Poland.

The differences between the Lwów and the Warsaw school grew up slowly and almost imperceptibly, to become accentuated only in the late ‘twenties. By 1930 Leśniewski’s system of the foundations of logic and mathematics, which was to avoid the shortcomings of Principia Mathematica, was emerging from the privacy of lectures, seminars, and personal contacts into print[19]. Łukasiewiczs investigations on the propositional calculus, Aristotle’s syllogistic, many-valued logics, and history of logic, were summarised in a number of articles and reports[20]. Two important text-books of formal logic were published, which, as it were, codified various discoveries made in Poland and abroad, incorporated them into the body of common philosophical knowledge, and set a pattern for teaching of and research in logic[21]. Tarski, who since 1923 made a number of important contributions, clearly joined his teachers as the third leader of the logical school and became responsible for initiating systematic studies in rectalogic and semantics[22]. Kotarbiński Elements of the Theory of Knowledge, Formal Logic and Methodology of Science was just published and showed how the general assumptions of the school were applied in practice and what they could achieve[23]. The leading logicians, Leśniewski, Łukasiewicz, and Tarski, and the most prominent philosophers, Kotarbiński and Ajdukiewicz, were by that time surrounded by a large number of young assistants and followers who had already made their mark in logic or philosophy. The school also had adherents outside Warsaw, in Lwów, Poznań, and Wilno, Kraków jealously guarding its independence both in logic and philosophy, and exercised a considerable influence on the minds of the younger generation studying at the universities or starting their own research. The Warsaw school was clearly the dominant force in academic philosophy and a powerful stimulus in the intellectual life of the country.

The Warsaw school had its logical and its philosophical wing without losing its unity. The unity was the manifestation of a personal union of logic and philosophy, represented by Leśniewski and Łukasiewicz, reinforced by the mutual influence which the pure logicians and the philosophers were exercising on each other. In this respect Tarski, who is a logician and mathematician, represented a new departure which, in the course of time, was to assert itself increasingly in the development of the school. While the older generation of logicians represented the alliance of philosophy and formal logic, the younger generation of logicians combined logic and mathematics, drew away from philosophy and were becoming more and more absorbed in and by the mathematical school. This trend has become very pronounced after the Second World War. Although its origin could be traced already in the ‘thirties, it did not affect the unity of the Warsaw school at that time.