Abstract
Presentations like this have several objectives. The main one is, of course, to honor the person whose name is given to the lecture; that is, to make a public and distinct recognition of his activities. The occasion could be used also to remember his qualities, to point out aspects of his experiences which might be useful for the understanding or solution of current problems, and to point out examples which deserve to be followed. In summary, to find inspiration in his life. Another objective is to discuss some topics which might be related to the ideals of the person honored and to perpetuate his memory in this way. Having been invited to deliver the second Fred L. Soper Lecture, I appreciate the undeserved honor which has been bestowed upon me. There are indeed many persons with higher qualifications than myself to accomplish this important task.