Cruel persecutions and intolerance are not accidents, but grow out of the very essence of religion, namely, its absolute claims.

Wisdom is not to be obtained from textbooks, but must be coined out of human experience in the flame of life.

It is not impossible to think that the minds of philosophers sometimes act like those of other mortals, and that, having once been determined by diverse circumstances to adopt certain views, they then look for and naturally find reasons to justify these views.

It has generally been assumed that of two opposing systems of philosophy, e.g., realism and idealism, one only can be true and one must be false; and so philosophers have been hopelessly divided on the question, which is the true one.

If a philosophic theory is once ruled out of court, no one can tell when it will appear again.

Conservatism clings to what has been established, fearing that, once we begin to question the beliefs that we have inherited, all the values of life will be destroyed.

Liberalism is an attitude rather than a set of dogmas - an attitude that insists upon questioning all plausible and self-evident propositions, seeking not to reject them but to find out what evidence there is to support them rather than their possible alternatives.