The average man does not know what to do with his life, yet wants another one which will last forever.

Confidence isn't optimism or pessimism, and it's not a character attribute. It's the expectation of a positive outcome.

切勿用权力去压制你认为不利的意见，因为如果你发表意见时也会遭到压制。

In the context of computational learning, the concept of 'probably approximately correct' (PAC) learning provides a framework for understanding the efficiency and feasibility of learning algorithms.