Imagination is the creative module of the brain. It provides the generation of alternatives that is useful in the problem solving ability. It provides fiction writers with plots, stories, details, and all that rich tapestry of stuff. There is a separate area of visual storage that some are so good at. Some of us can ID an image, but I could not tell you what was on it before I see it. Seneca describes a horse with such a memory, no clue until the recognize something familiar.
There is a executive testing function as well, that sets up tests to separate real from fiction, and also to test those solutions to problem as to possible or if the idea should be left in the field to grow or change into something else. Let x equal the answer, or let x equal the time, distance, or something else, and y something else, and the answer is the the solution of the equation(s) generated, or the matrix resolved.
As the equations become more complex, the solutions become more textbook based. I still remember a few "method of integration" like look up the solution in the Canadian Rubber Company handbook or in the back cover of Thompson.
It is our ability to generate alternatives that creates decision making processes. We can then set up criteria to judge those possibilities and pick the "best" solution. But so often the criteria require future knowledge, or knowledge of the future to accurately evaluate, and sometimes only crudely evaluate. We need to act on faith, rather than on any real knowledge. Faith in what though, that the world will keep turning? That the work will come? That oil will come back to profitability? That the government will have the balls to do what is necessary? Deport ISIL's... or those who do not behave like those idiots in Cologne who are not yet citizens? Or to run Trump out of town, or should you all just elect him?
The Koreans need to do a big hydrogen bomb test to prove that they can, and the same time radiate themselves a bit more. After having tasted freedom, no one would want there oppressive system. But if anyone bothers there sovereignty, look out. All religious promotion is forbidden, and subject to the death penalty and that is sovereignty. Oh well.
But what do I know?