The main of the most important contentions of Ajdukiewicz’s philosophy and epistemology is that the classical theory of truth, in contrast to the non-classical theory of truth, is the only correct explanation of the problem of truth. The key argument of Ajdukiewicz’s conception is the adequate interpretation of the term correspondence. According to Ajdukiewicz, by the term correspondence we should understand neither similarity between thought and reality nor their identity nor reflection. The Polish philosopher claims that correspondence means that thought affirms the state of affairs. On this basis, pivotal arguments against the classical theory of truth could be rejected.