The existence of very pious feelings, in conjunction with intolerance, cruelty, and selfish policy, has never ceased to surprise and perplex those who have viewed it calmly from a distance. ... It is impossible to exaggerate the evil work theology has done in the world. What destruction of the beautiful monuments of past ages, what waste of life, what disturbance of domestic and social happiness, what perverted feelings, what blighted hearts, have always marked its baneful progress!

[U]sefulness is happiness, and... all other things are but incidental.

the excess of all good things is mischievous.

Prejudices of all kinds have their strongest holds in the minds of the vulgar and the ignorant.

A human heart can never grow old if it takes a lively interest in the pairing of birds, the reproduction of flowers, and the changing tints of autumn leaves.

Love is the divine quality that everywhere produces and restores life. To each and every one of us, it gives the power of working miracles if we will.

Birds and beasts have in fact our own nature, flattened a semi-tone.