Heidegger's analysis of modern science and especially Descartes' philosophy drawn in 1930s represents a significant shift contrary to the theoretical research in his work called Being and Time. While the main problem in the most significant Heidegger's work is the analysis of res extensa in Descartes' philosophy, later in Modern Mathematical Natural Science and in Age of the World Picture the main problem turns to be a picture of Descartes as a methodologist. By this theoretical research Heidegger tends to lead us to the knowledge that only by deep immersion into the problems of The principle of Reason we can gain the knowledge or the intuition of what happens in modern science. Here we also can reach the turning-point of the history of hum...