functional programming has the same use to a programmer as category theory does to a mathematician. It is very good at describing the kind of objects we tend t

functional programming has the same use to a programmer as category theory does to a mathematician. It is very good at describing the kind of objects we tend to care about, so it is sensible to consider the converse and ask what kinds of things is it good at describing. how naturally we can express our code is a very strong measure of how well we understand it. Both in terms of what it can and cant do. Imagine having blocks that stick together like legos, but you cant see the dot lattice because your vision is too poor. FP is about seeing the dots.