For what man has sought for is, indeed, neither pain nor pleasure, but simply Life. Man has sought to live intensely, fully, perfectly. When he can do so without exercising restraint on others, or suffering it ever, and his activities are all pleasurable to him, he will be saner, healthier, more civilised, more himself. Pleasure is Nature's test, her sign of approval. When man is happy, he is in harmony with himself and his environment.
The Soul of Man Under Socialism (1895)