Our lives are universally shortened by our ignorance.

The behavior of men to the lower animals, and their behavior to each other, bear a constant relationship.

The great aim of education is not knowledge but action.

The wise man must remember that while he is a descendant of the past, he is a parent of the future.

Those who have never entered upon scientific pursuits know not a tithe of the poetry by which they are surrounded.

We all decry prejudice, yet are all prejudiced.

In science the important thing is to modify and change one's ideas as science advances.

Old forms of government finally grow so oppressive that they must be thrown off even at the risk of reigns of terror.

Science is organized knowledge.

Society exists for the benefit of its members, not the members for the benefit of society.

The preservation of health is a duty. Few seem conscious that there is such a thing as physical morality.

Volumes might be written upon the impiety of the pious.

What a cage is to the wild beast, law is to the selfish man.

The fact disclosed by a survey of the past that majorities have been wrong must not blind us to the complementary fact that majorities have usually not been entirely wrong.

The more specific idea of Evolution now reached is - a change from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity, accompanying the dissipation of motion and integration of matter.

The Republican form of government is the highest form of government: but because of this it requires the highest type of human nature, a type nowhere at present existing.

No one can be perfectly free till all are free; no one can be perfectly moral till all are moral; no one can be perfectly happy till all are happy.

Life is the continuous adjustment of internal relations to external relations.

All socialism involves slavery.

Love is life's end, but never ending. Love is life's wealth, never spent, but ever spending. Love's life's reward, rewarded in rewarding.