Imagine being a slave in ancient Rome. Now remember being one. The second task, unlike the first, is crazy. If, as I’m guessing, you never were a slave in ancient Rome, it follows that you can’t remember being one — but you can still let your imagination rip. With a bit of effort one can even imagine the impossible, such as discovering that Dick Cheney and Madonna are really the same person. It sounds like a platitude that fiction is the realm of imagination, fact the realm of knowledge.
Why did humans evolve the capacity to imagine alternatives to reality? Was story-telling in prehistoric times like the peacock’s tail, of no direct practical use but a good way of attracting a mate? It kept Scheherazade alive through those one thousand and one nights — in the story.
On further reflection, imagining turns out to be much more reality-directed than the stereotype implies. If a child imagines the life of a slave in ancient Rome as mainly spent watching sports on TV, with occasional household chores, they are imagining it wrong. That is not what it was like to be a slave. The imagination is not just a random idea generator. The test is how close you can come to imagining the life of a slave as it really was, not how far you can deviate from reality.
A reality-directed faculty of imagination has clear survival value. By enabling you to imagine all sorts of scenarios, it alerts you to dangers and opportunities. You come across a cave. You imagine wintering there with a warm fire — opportunity. You imagine a bear waking up inside — danger. Having imagined possibilities, you can take account of them in contingency planning. If a bear is in the cave, how do you deal with it? If you winter there, what do you do for food and drink? Answering those questions involves more imagining, which must be reality-directed. Of course, you can imagine kissing the angry bear as it emerges from the cave so that it becomes your lifelong friend and brings you all the food and drink you need. Better not to rely on such fantasies. Instead, let your imaginings develop in ways more informed by your knowledge of how things really happen.
http://opinionator.blogs.nytimes.com/2010/08/15/reclaiming-the-imagination/?th&emc=th