Boys and girls should be taught respect for each other's liberty... and that jealousy and possessiveness kill love.

One is always a little afraid of love, but above all, one is afraid of pain or causing pain.

How much longer is the world willing to endure this spectacle of wanton cruelty?

I do not think any reasonable person can doubt that in India, China and Japan, if the knowledge of birth control existed, the birthrate would fall very rapidly

A process which led from the amoeba to man appeared to the philosophers to be obviously a progress though whether the amoeba would agree with this opinion is not known.

History is valuable, to begin with, because it is true; and this, though not the whole of its value, is the foundation and condition of all the rest. That all knowledge, as such, is in some degree good, would appear to be at least probable; and the knowledge of every historical fact possesses this element of goodness, even if it posses no other.

The great majority of men and women, in ordinary times, pass through life without ever contemplating or criticising, as a whole, either their own conditions or those of the world at large.