Worry is interest paid on trouble before it comes due.

The modern world belongs to the half-educated, a rather difficult class, because they do not realize how little they know.

What is originality? Undetected plagiarism.

Let none of us delude himself by supposing that honesty is always the best policy. It is not.

All human love is a holy thing, the holiest thing in our experience.

Over-population is a phenomenon connected with the survival of the unfit, and it is a mechanism which has created conditions favourable to the survival of the unfit and the elimination of the fit.

The fruit of the tree of knowledge always drives man from some paradise or other; and even the paradise of fools is not an unpleasant abode while it is habitable.