The melancholy science from which I make this offering to my friend relates to a region that from time immemorial was regarded as the true field of philosophy, but which, since the latter's conversion into method, has lapsed into intellectual neglect, sententious whimsy, and finally oblivion.

你的热情应该大于你的恐惧。

Great deeds are usually wrought at great risks.

可持续发展不是一种选择，而是我们对后代的责任。