出自先秦《荀子·性恶》引古语。不知儿子的为人，看看他的朋友就清楚了；不知国君是否贤明，看看他左右的大臣是什么德行就知道了。
The most reliable way to anticipate the future is by understanding the present.
The truth is, the science of Nature has been already too long made only a work of the brain and the fancy: It is now high time that it should return to the plainness and soundness of observations on material and obvious things.
