The aim of this study is to highlight two interesting aspects of Masaryk’s relation to Kant against the background of the personality and influence of Masaryk’s Viennese teacher Franz Brentano and Brentano’s own relation to Kant’s philosophy. It helps to treat of two periods in Masaryk’s intellectual endeavour in relation to the particular in science, ethics and religion. In the first period, which is generally accompanied by a cold and reticent approach to Kant, Masaryk rejects the epistemological foundations of Kant’s philosophy (apriorism and the doctrine of the unknowability of the thing in itself), and instead, given his leaning towards positivism, places emphasis on the general method of scientific knowledge and its importance for philosophy. In this early period of his critical attitude to Kant we may tend towards the opinion that the personality of his teacher Franz Brentano stands behind Masaryk’s radical methodological rejection of Kant’s philosophy. The conspicuous similarity between Masaryk’s and Brentano’s conclusions on refuting Hume’s scepticism by the probability calculus caught the attention of Brentano’s pupils, Marty and Stumpf, who were working in Prague. Brentano, however, rejected any role in influencing Masaryk’s philosophical conclusions. The independence of Masaryk’s approach to the solution of this question is confirmed by correspondence he had with the young Husserl in 1878. In the next period, however, the radicalness recedes and Masaryk’s own personal approach to Kant’s philosophy becomes much more evident, as is shown in the background to the three-volume work Russia and Europe (1913). Masaryk’s ideas are not enriched only by the contrast between Russian and European thinking. A systematic study of Russian philosophy and literature enables him to penetrate deeper into the spiritual foundation of Russian thought. He thus uncovers a new creative dimension which is the starting point for a reevaluation of the significance of individual western European thinkers against the background of a different tradition. This is in particular true of the new view of Kant’s practical philosophy which serves Masaryk as a counter-argument to the mysticism and mythicality which form the fabric of the irrationality of Russian thought. The significance of Kant’s critical philosophy in the struggle against irrationality in thinking, as well as the emphasis on the example of Tolstoy’s rationalistic ethics and conscience, together indicate that Masaryk’s ethics had broken out of the framework of traditional positivism and he was endorsing a more modern subjectivist thought. Masaryk did not, however, abandon his negative view of Kant’s epistemology.