So long as there is death there will be sorrow, and so long as there is sorrow it can be no part of the duty of human beings to increase its amount, in spite of the fact that a few rare spirits know how to transmute it.

Ideas and principles that do harm are as a rule, though not always, cloaks for evil passions.

In the visible world, the Milky Way is a tiny fragment; within this fragment, the solar system is an infinitesimal speck, and of this speck our planet is a microscopic dot. On this dot, tiny lumps of impure carbon and water, of complicated structure, with somewhat unusual physical and chemical properties, crawl about for a few years, until they are dissolved again into the elements of which they are compounded.

Almost all education has a political motive.

Laughter is the most inexpensive and most effective wonder drug. Laughter is a universal medicine.

Although this may seem a paradox, all exact science is dominated by the idea of approximation. When a man tells you that he knows the exact truth about anything, you are safe in inferring that he is an inexact man. Every careful measurement in science is always given with the probable error ... every observer admits that he is likely wrong, and knows about how much wrong he is likely to be.

Is a man what he seems to the astronomer, a tiny lump of impure carbon and water crawling impotently on a small and unimportant planet? Or is he what he appears to Hamlet? Is he perhaps both as once?