To have seen Italy without having seen Sicily is to not have seen Italy at all, for Sicily is the clue to everything.

Such is the frailty of man that even where he makes the truest and most forcible impression in the memory, in the heart of his beloved, there also he must perish.

With the growth of knowledge our ideas must from time to time be organized afresh. The change takes place usually in accordance with new maxims as they arise, but it always remains provisional.

Truth is a torch but a tremendous one. That is why we hurry past it, shielding our eyes, indeed, in fear of getting burned.

He who would reproach an author for obscurity should look into his own mind to see whether it is quite clear there. In the dusk the plainest writing is illegible.

There is nothing so terrible as activity without insight.

To tremble before anticipated evils is to bemoan what thou hast never lost.