In order that this state of affairs may come into view for us, however, there must be adequate clarity about what science is. But how shall we come to know that? Most surely, it seems, simply by describing the scientific enterprise of our day. Such a presentation could show how, for a long time, ever more decisively and at the same time ever more unobtrusively, the sciences have been intersecting in all organizational forms of modern life : in industry, in commerce, in education, in politics, in warfare, in journalism of all kinds. To be acquainted with this intersecting is important. In order to be able to give an exposition of it, however, we must first have experienced that in which the essence of science lies. This may be expressed in one concise statement. It runs : Science is the theory of the real.
This statement intends to provide neither a ready definition nor an easy formula. It contains nothing but questions. They emerge only when the statement is clarified. We must observe first of all that the name "science" [Wissenschaft] in the statement "Science is the theory of the real" always refers exclusively to the new science of modern times. The statement "Science is the theory of the real" holds neither for the science of the Middle Ages nor for that of antiquity. Medieval doctrina is as essentially different from a theory of the real as it is different when contrasted with the ἐπιστήμη of the ancients. Nevertheless, the essence of modern science, which has become world-wide meanwhile as European science, is grounded in the thinking of the Greeks, which since Plato has been called philosophy.
With these considerations, the revolutionary character of the modern kind of knowing is in no way being weakened. Quite to the contrary, the distinctive character of modern knowing [Wissens] consists in the decisive working out of a tendency that still remains concealed in the essence of knowing as the Greeks experienced it and that precisely needs the Greek knowing in order to become, over against it, another kind of knowing.
Whoever today dares, questioningly, reflectingly, and, in this way already as actively involved, to respond to the profundity of the world shock that we experience every hour, must not only pay heed to the fact that our present-day world is completely dominate d by the desire to know of modern science; he must consider also, and above all else, that every reflection upon that which now is can take its rise and thrive only if, through a dialogue with the Greek thinkers and their language, it strikes root into the ground of our historical existence.