Man is by nature competitive, combative, ambitious, jealous, envious, and vengeful.

Man is by nature competitive, combative, ambitious, jealous, envious, and vengeful.

The main force used in the evolving world of humanity has hitherto been applied in the form of war.

I prize the conditions under which I have lived because they have permitted me to choose my opportunities, to inquire into such matters as interested me, and to publish what I believed to be true, uncontrolled by any central authority.

It is just because civilization is ever evolving, changing, and becoming more complicated, that experts find it so difficult to define it in explicit terms.

No tempting form of error is without some latent charm derived from truth.

Before the discovery of agriculture mankind was everywhere so divided, the size of each group being determined by the natural fertility of its locality.