The article discusses both Tillich and Kierkegaard in the perspective of differential thinking. Differential thinking, initiated by Schelling, is not build on the binary opposition between sensing and thinking, but sensing belongs to thinking and vice versa. The development of subjectivity in Kierkegaard is expressed in that how the individual senses his or her existence (how-truth). The how-truths are differentiated from the what-truths of modern scientific knowledge. What-truths are objective representations; how-truths express the sensed. The paper discusses also the difference between negative and positive philosophy in religious knowledge. Both Tillich and Kierkegaard seem to follow Schelling in differentiating between the two. The negative philosophy, based on radical doubt, takes the possibility of objective knowledge of God away. The positive philosophy both in Tillich and in Kierkegaard opens up for the metaphorical and the symbolic. The metaphorical expresses the sensed; religious knowledge speaks the language of how-truths.