William James, the great psychologist, said that most men are "old fogies at twenty-five",He was right. Most men at twenty-five are satisfied with their jobs. They have accumulated the little stock of prejudices that they call their "Principles, " and closed their minds to all new ideas; they have ceased to grow.

　　The minutea man ceases to grow-no matter what his years-that minute he begins to be old. On the other hand, the really great man never grows old.

　　Goethe passed out at eighty-three, and finished his Faust only a few years earlier; Gladstone took up a new language when he was seventy.

　　Laplace, the astronomer, was still at work when death caught up with him at seventy-eight. He died crying, "What we know is nothing; what we do not know is immense."

　　And there you have the real answer to the question, "When is a man old?"

　　Laplace at seventy-eight died young. He was still unsatisfied, still sure that he had a lot to learn.

　　As long as a man can keep himself in that attitude of mind, as long as he can look back on every year and say , "I grew," he is still young.

　　The minute he ceases to grow, the minute he says to himself, "I know all that I need to know,"--that day youth stops. He may be twenty-five or seventy-five, it makes no difference. On that day he begins to be old.

　　[参考译文]

　　“我惧怕临近岁末年尾”，一位朋友最近对我说：“它使我意识到我正在变老。”

　　伟大的心理学家威廉·詹姆斯就曾说过，大多数人“25岁时就成了守旧落伍者”。他的话是对的。大多数人25岁时就满足于他们的工作。他们已经积累了一些他们称之为“原则”的偏见，对所有新的思想关闭心灵之门；他们已经停止成长。

　　一个人一旦停止成长--不管他年龄多大--他就开始衰老。反之，真正的伟人从来不会衰老。

　　歌德享年83岁，逝世前几年才完成《浮士德》；格莱斯顿70岁时又开始学习一门外国语；法国天文学家拉普拉斯78岁死时还在工作着。临死前，他大声喊道：“我们所知的太少太少，我们所不知的太多太多。”

　　“一个人何时变老？”，从这类事例中对这个问题你已经有了真正的答案。

　　拉普拉斯78岁逝世时依然年轻。他依旧不满足，依旧感到许多东西要学。

　　一个人，只要他能够保持这种心态，只要他在回首过去的一年时能够说“我在成长”，他就依然年轻。

　　他一旦停止成长，他一旦对自己说“我该懂的都懂了”，这个时候他的青春也就完了。他可能在25岁时死去，也可能在75岁时死去，这都没有区别。就在那一天，他开始变老。