Even the humblest mammal's strong sexual, parental, and social instincts give rise to 'do unto others as yourself' and 'love thy neighbor as thyself'.

There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

Ultimately a highly complex sentiment, having its first origin in the social instincts, largely guided by the approbation of our fellow-men, ruled by reason, self-interest, and in later times by deep religious feelings, confirmed by instruction and habit, all combined, constitute our moral sense or conscience.

The moral faculties are generally and justly esteemed as of higher value than the intellectual powers.

I had gradually come, by this time [1839-01], to see that the Old Testament from its manifestly false history of the world, with the Tower of Babel, the rainbow as a sign, etc., etc. and from its attributing to God the feelings of a revengeful tyrant, was no more to be trusted than the sacred books of the Hindoos, or the beliefs of any barbarian.

It is not the conscience which raises a blush, for a man may sincerely regret some slight fault committed in solitude, or he may suffer the deepest remorse for an undetected crime, but he will not blush... It is not the sense of guilt, but the thought that others think or know us to be guilty which crimsons the face.

If I had life to live over again, I would give my life to poetry, to music, to literature, and to art to make life richer and happier. In my youth I steeled myself against them and thought them so much waste.