Pure mathematics consists entirely of assertions to the effect that, if such and such a proposition is true of anything, then suchand such another proposition is true of that thing.... Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.

Boys and young men acquire readily the moral sentiments of their social milieu, whatever these sentiments may be.

Moral progress has consisted in the main of protest against cruel customs, and of attempts to enlarge human sympathy.

Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths.

To realize the unimportance of time is the gate to wisdom.

The knowledge exists by which universal happiness can be secured; the chief obstacle to its utilization for that purpose is the teaching of religion. Religion prevents our children from having a rational education; religion prevents us from removing the fundamental causes of war; religion prevents us from teaching the ethic of scientific cooperation in place of the old fierce doctrines of sin and punishment. It is possible that mankind is on the threshold of a golden age; but, if so, it will be necessary first to slay the dragon that guards the door, and this dragon is religion.

Belief in a Divine mission is one of the many forms of certainty that have afflicted the human race.