乐观主义者认为这是所有可能世界中最好的一个。悲观主义者则担心这是真的。
君主所凭借着驱使臣下的，只有尚贤一种方法；臣下用来侍奉君主的，也只有仁义一条途径。
I don't know what's tighter, my jeans or my security.
The aim of education should be to teach us rather how to think, than what to think—rather to improve our minds, so as to enable us to think for ourselves, than to load the memory with thoughts of other men.
It is not what we believe, but why we believe it; moral responsibility begins there.
Mathematics is the organ with which we comprehend the phenomena of nature.