This paper discusses the relationship between science and common sense in the philosophy of Canadian catholic theologian and philosopher Bernard Lonergan, especially in his opus vitae : Insight : A Study of Human Unserstanding (London, 1957. Toronto : The Critical Edition, 1992). It deals with the similarities and differences between science and common sense and also seeks the answer to the question of what kind of relation exists between them (conflict, cooperation, or indifference). To discuss Lonergan’s position, Monika Walczak addresses the following issues : – 1. B. Lonergan’s philosophical achievements and influence; – 2. A general account of his philosophy; – 3. The notion of science; – 4. The notion of common sense; – 5. Relations between science and common sense (similarities, differences, complementarity).