Good wishes alone will not ensure peace.

The savants will write excellent volumes. There will be laureates. But wars will continue just the same until the forces of the circumstances render them impossible.

One can state, without exaggeration, that the observation of and the search for similarities and differences are the basis of all human knowledge.

Perhaps my dynamite plants will put an end to war sooner than your [pacifist] congresses. On the day two army corps can annihilate each other in one second all civilized nations will recoil from war in horror.

If I have a thousand ideas and only one turns out to be good, I am satisfied.

A heart can no more be forced to love than a stomach can be forced to digest food by persuasion.

To his sister-in-law: What a contrast between us! You live a warm and glowing life, surrounded by loved ones whom you care for and who care for you; you are anchored in contentment. I drift about without rudder or compass, a wreck on the sea of life; I have no memories to cheer me, no pleasant illusions of the future to comfort me, or about me to satisfy my vanity. I have no family to furnish the only kind of survival that concerns us, no friends for the wholesome development of my affections, or enemies for my malice.