Human, All Too Human: A Book For Free Spirits / quote 32 of 58
Actions can be promised, but not feelings, for these are involuntary
What Can be Promised.—Actions can be promised, but not feelings, for these are involuntary. Whoever promises somebody to love him always, or to hate him always, or to be ever true to him, promises something that it is out of his power to bestow. But he really can promise such courses of conduct as are the ordinary accompaniments of love, of hate, of fidelity, but which may also have their source in motives quite different: for various ways and motives lead to the same conduct. The promise to love someone always, means, consequently: as long as I love you, I will manifest the deportment of love; but if I cease to love you my deportment, although from some other motive, will be just the same, so that to the people about us it will seem as if my love remained unchanged.—Hence it is the continuance of the deportment of love that is promised in every instance in which eternal love (provided no element of self deception be involved) is sworn.