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Words can be both wounds and bandages.

要理解遞歸，首先必須理解遞歸。

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.

If you're not failing, you're not trying hard enough.

數學中最深刻的見解往往來自最抽象的理論。

恐懼只是一種心態。