Up till now two fundamental concepts of faith (religion) and knowledge (science) have been used in Christianity. In this way the Greek tradition, and especially old-Christian one, is followed, the tradition that distinguished the world of knowledge that is a product of the cognizing mind from the world of revelation that accepts God's non-scientific gift. Christianity’s whole effort was directed at indicating the differences between science and revelation, and then at showing harmony, or at least non-contradiction, between them. This is why Anton Grabner-Haider (*1940), an Austrian philosopher of religion, had to take into consideration also the world of thought comprising science and the world of the experience of faith, including revelation. In turn, he presented the mutual relations between these worlds, understanding science on the ground of the neopositivist conception and faith on the ground of the Church’s popular contemporary understanding of faith. It is a pity he does not use the strictly theological concept of faith, and especially the more modern personalist conception, despite verbally referring to personalism. However, making modern attempts at shifting the problem of faith and knowledge as well as of their mutual relations onto the basis of the language is exactly Grabner-Haider’s achievement. In this way a new situation arises, in which not so much the world of ideas and thoughts opposes the world of religious experience and revelation, as the world of one or two languages does.