My method to overcome a difficulty is to go round it.

Look around when you have got your first mushroom or made your first discovery: they grow in clusters.

There exist a lot of questions that the fools can ask, and the intelligent cannot answer.

Epitaph on Newton: Nature and Nature's law lay hid in night: God said, "Let Newton be!," and all was light. [added by Sir John Collings Squire: It did not last: the Devil shouting "Ho. Let Einstein be," restored the status quo] [Aaron Hill's version: O'er Nature's laws God cast the veil of night, Out blaz'd a Newton's soul and all was light.

An idea which can be used only once is a trick. If one can use it more than once it becomes a method.

In order to translate a sentence from English into French two things are necessary. First, we must understand thoroughly the English sentence. Second, we must be familiar with the forms of expression peculiar to the French language. The situation is very similar when we attempt to express in mathematical symbols a condition proposed in words. First, we must understand thoroughly the condition. Second, we must be familiar with the forms of mathematical expression.

Mathematics is not a spectator sport!