"The influence of [Kazimierz] Twardowski on modern philosophy in Poland is all-pervasive. Twardowski instilled in his students a passion for clarity [...] and seriousness. He taught them to regard philosophy as a collaborative effort, a matter of disciplined discussion and argument, and he encouraged them to train themselves thoroughly in at least one extra-philosophical discipline and to work together with scientists from other fields, both inside Poland and internationally. This led above all [...] to collaborations with mathematicians, so that the Lvov school of philosophy would gradually evolve into the Warsaw school of logic [...]. Twardowski taught his students, too, to respect and to pursue serious research in the history of philosophy, an aspect of the tradition of philosophy on Polish territory which is illustrated in such disparate works as [Jan] Lukasiewicz's ground-breaking monograph on the law of non-contradiction in Aristotle and [Wladyslaw] Tatarkiewicz's highly influential multi-volume histories of philosophy and aesthetics [...] The term 'Polish philosophy' is a misnomer [...] for Polish philosophy is philosophy per se; it is part and parcel of the mainstream of world philosophy - simply because [...] it meets international standards of training, rigour, professionalism and specialization." - Barry Smith (from: "Why Polish Philosophy does Not Exist")

The volume contains almost thirty papers by Kazimierz Twardowski (1866-1938), the founder of the Lvov-Warsaw School. The papers are published in English for the first time. The papers concern fundamental problems of philosophy: the methods of philosophizing, the boundary of psychology and semiotics, the conceptual apparatus of metaphysics, ethical skepticism, the question of free will and ethical obligation, the aesthetics of music and so on. The systematic considerations are complemented by concise but excellent sketches of the philosophical views of Socrates, Aquinas, Leibniz, Spencer, Nietzsche, and Bergson.

The Lvov-Warsaw School was one of the most important currents in the 20th-century analytical movement. Kazimierz Twardowski, a student Franz Brentano and a professor of philosophy in Lvov, was the founder and at the same time an outstanding representative of the School. The papers included into the volume present comprehensively Twardowski's views and indicate what his lasting contribution to philosophy consists of.

In 1906, Jan Lukasiewicz, a great logician, published his classic dissertation on the concept of cause, containing not only a thorough reconstruction of the title concept, but also a systematization of the analytical method. It sparked an extremely inspiring discussion among the other representatives of the Lvov-Warsaw School. The main voices of this discussion are supplemented here with texts of contemporary Polish philosophers. They show how the concept of cause is presently functioning in various disciplines and point to the topicality of Lukasiewicz's method of analysis.