我的工作主要涉及一个抽象的主题:人类知识,特别是科学知识的问题。我是一个乐观主义者。我是这样一个世界中的乐观主义者,在那里一个人如果想要“生存”,他必须是一个悲观主义者,这在知识界已成了一条严格的规律。但是我确信,我们的时代并不象人们通常认为的那样糟;我确信,我们的时代比它的名声好得多。四分之一世纪以前,我曾作过一次演讲, My work mainly involves an abstract theme: the problem of human knowledge, especially of scientific knowledge. I am an optimist. I am an optimist in a world where one must be a pessimist if he wants to “survive,” which is a strict law in the intellectual world. But I am convinced that our times are not as bad as people usually think, and I am sure that our time is far better than its reputation. A quarter of a century ago, I had a speech,