The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.

量子力学的本质不在于描述粒子的行为，而在于描述我们对粒子认知的行为。

The PAC learning framework provides a formal way to analyze the efficiency and effectiveness of learning algorithms.

"We are all ghosts of our former selves, haunting the places we once knew."

We’re still the best band in the world.