People must have renounced, it seems to me, all natural intelligence to dare to advance that animals are but animated machines.... It appears to me, besides, that such people can never have observed with attention the character of animals, not to have distinguished among them the different voices of need, of suffering, of joy, of pain, of love, of anger, and of all their affections. It would be very strange that they should express so well what they could not feel.
Actual philosophers... are commanders and law-givers: they say "thus it shall be!", it is they who determine the Wherefore and Whither of mankind, and they possess for this task the preliminary work of all the philosophical laborers, of all those who have subdued the past - they reach for the future with creative hand, and everything that is or has been becomes for them a means, an instrument, a hammer.
All literature, all philosophical treatises, all the voices of antiquity are full of examples for imitation, which would all lie unseen in darkness without the light of literature.
The past is past, and the future is yet to come. That means the future is in your hands - the future entirely depends on the present. That realization gives you a great responsibility.