Here's a rule thumb that's important, and the older I get, the more important I think it is. When I can do something, and somebody wants me to do it, I have to do it. The great tragedy of life is not to be needed. As long as you are able and willing to do things for people, you will be needed. Of course you are able; and if so, you can't say no. My mother is seventy-seven. In seventy-seven years she has never said no. Today she is so much in demand by thirteen grandchildren and countless neighbors that her presence is eagerly contended for. When I want to see her I have to pretend emergency.

此外，還有一條經驗法則同樣重要。隨著慢慢長大，我也越來越認識到它的重要性。當我有能力做一件事，有人也希望我做時，我就必須去做。不為人所需是人生中最大的悲劇。只要你有能力并愿意為人們做一些事，人們就會需要你。你肯定能夠做到，那就不要推辭。我的母親已經77歲了。但77年來她從未說過“不”字。如今，她的13個孫兒和無數的鄰居依然很需要她，希望她能在身邊。因此當我想見她時，不得不假裝有緊急的事情。

Then there's the rule of curiosity. Your body would die if you stopped feeling hunger and thirst, and your mind will die if you lose your curiosity. This I learned from my father. My father was a naturalist. He could see the beetle under the bark, and draw it forth unharmed for us to squint at through the magnifying glass. He sampled the taste of thirty-three different caterpillars. Fired by his example, once, my sister ate an ant. In case you are wondering, caterpillars taste like the green leaves they eat, and ants taste of lemon. I personally haven't tasted any entomological specimens lately, but I am still rejoicing in the limitless curiosity, the draws me to books and people and places.I hope I never lose it. It would be like pulling down the blind.

除此之外，還有好奇法則。當你感覺不到饑餓和干渴時，你的身體就停止運轉了；如果你失去了好奇心，那你的思想就不再工作了。這是父親傳授給我的。他是一位博物學家。他能看到樹皮下的甲蟲，并把它毫發無傷地捉下來，放在放大鏡下讓我們看。他嘗過33種不同毛蟲的味道。有一次，在父親的示范與鼓勵下，妹妹吃了一只螞蟻。假如你對它們的味道感到好奇，我會告訴你，毛蟲的味道就像它們所吃的樹葉，而螞蟻的味道像檸檬。我個人最近并未品嘗任何昆蟲的標本，但我仍欣喜于自己無限的好奇心，它促使我博覽群書、樂于與人交往和四處旅行。我希望永遠擁有好奇心。沒有它，就仿佛放下了窗簾，讓我無法欣賞到窗外的美景。