For me, scientific knowledge is divided into mathematical sciences, natural sciences or sciences dealing with natural world, and sciences dealing with mankind. Apart from these sciences is philosophy. All this is pure or (62) knowledge, sought only for the (63) of understanding in order to fulfill the need to understand what is intrinsic and consubstantial (同质的) to man. What () man from animal is that he knows and needs to know. If man did not know that the world existed, and that the (65) was of a certain kind, that he was in the world and that he himself was of a certain kind, he wouldn’t be man. The technical aspects or applications of knowledge are equally necessary for man and are of the greatest importance, (66) they also contribute to (67) him as man and permit him to (68) a life increasingly more truly human. (69) even while enjoying the results of technical progress, (70) must defend the primacy and autonomy of our knowledge. Knowledge sought (71) for its practical applications will have immediate and (72) success, but not the kind of important result (73) revolutionary scope is in large part unforeseen, except by the imagination of the Utopians. Let me recall a well-known example. If the Greek mathematicians had not applied themselves (74) investigation of conic (二次曲线) sections zealously and without the least suspicion (75) it might someday be useful, it would not have been possible (76) later to navigate far from shore. The first man to study the nature of electricity could not imagine that their experiments, carried on because of mere (77) curiosity, would ually lead to modern electrical technology, without which we can scarcely (78) of contemporary life. Pure knowledge is valuable for its own sake, because the human spirit cannot (79) itself to ignorance. But, (80) it is the foundation for practical results that would not have been reached if this knowledge had not been sought (81) .