Life is wasted on the living....

A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.

He was a dreamer, a thinker, a speculative philosopher... or, as his wife would have it, an idiot.

Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.

Anyone who stops learning is old, whether at twenty or eighty. Anyone who keeps learning stays young. The greatest thing in life is to keep your mind young.

There is a fountain of youth: it is your mind, your talents, the creativity you bring to your life and the lives of people you love. When you learn to tap this source, you will truly have defeated age.

Life would be infinitely happier if we could only be born at the age of eighty and gradually approach eighteen.

Probably the happiest period in life most frequently is in middle age, when the eager passions of youth are cooled, and the infirmities of age not yet begun as we see that the shadows, which are at morning and evening so large, almost entirely disappear at midday.