For every expert there is an equal and opposite expert, but for every fact there is not necessarily an equal and opposite fact.
Mathematics is not about numbers, equations, computations, or algorithms: it is about understanding.
数学不是关于数字、方程、计算或算法的：它是关于理解的。
A picture must be a thing in itself, not a representation of something else.
对任何模型的最大期望是它能提供一个对现实有用的近似。