Chapter 1
Building Abstractions with Functions

The acts of the mind, wherein it exerts its power over simple ideas, are chiefly these three: 1. Combining several simple ideas into one
compound one, and thus all complex ideas are made. 2. The second is
bringing two ideas, whether simple or complex, together, and setting
them by one another so as to take a view of them at once, without
uniting them into one, by which it gets all its ideas of relations. 3. The third is separating them from all other ideas that accompany them in
their real existence: this is called abstraction, and thus all its general
ideas are made.
 John Locke, An Essay Concerning Human Understanding (1690)

这个是SICP JavaScript 改编版里面第一章cite的一段话,基本上讲透了我们思考问题所用的方法论