George Santayana,
Egotism in German Philosophy — Chapter XI. Nietzsche and Schopenhauer
(1916)
“ In these the travail of human nature appears; for human nature is not merely a name for a certain set of passions known to literature; in that sense Schopenhauer fully acknowledged it, and even thought it immutable; it is rather the constitution of an animal capable of training and development. What is more patent than that a man may learn something by experience and may be trained? But if he can be trained he is capable of adaptation and, therefore, of happiness, and the preposterous assertion that all desires are equally arbitrary and equally fruitless is blown to the winds. ”
