Simon Baron Cohen writes in entelechy on theories of imagination (scroll down):

In what sense might something as intrinsically human as the imagination be biological? How could the products of the imagination - a novel, a painting, a sonata, a theory - be thought of as the result of biological matter? After all, such artefacts are what culture is made of. So why invoke biology? In this essay, I will argue that the content of the imagination is of course determined more by culture than biology. But the capacity to imagine owes more to biology than culture.

Let's start with a few definitional issues. What do we mean by 'imagination'? I do not mean mere imagery, though clearly the imagination may depend on the manipulation of imagery. Imagery is usually the product of one of the five senses (though it can also be generated without any sensory input at all, from the mere act of thinking or dreaming). Imagery typically comprises a mental representation of a state of affairs in the outside, physical world. I don't want to put you off from reading this essay by littering it with jargon, so let's just think of a mental representation as a picture in your head. That is what we are going to be calling an image, but that is not the same as imagination. Consider why not.

When we create a visual image of a specific object in our mind, the image as a picture of the object has a more or less truthful relationship to that object or outside state of affairs. If the image is a good, faithful, representation, it depicts the object or state of affairs accurately in all its detail. So, mental images typically have 'truth relationships' to the outside world. Of course, to create imagery in the first place depends on having the relevant 'hardware'. To create a photo, one needs a camera. To create a mental image, one needs a sense organ hooked up to a brain. An eye can do the trick, since the retina contains receptors that can code both position and colour in sufficient detail for the brain to which it is hooked up to create an accurate image. But in the absence of an eye, clearly an ear or a finger can do the trick too. With your ear, you can create an image of where that owl might be. With your finger, you can create an image of where your car-keys are.

Imagery may be necessary for human imagination. It has been suggested that all the products of the imagination are derived from imagery, following some transformation of the basic imagery. For example, Rutgers' psychologist Alan Leslie, when he worked in London in the 1980s, proposed that imagination essentially involves three steps: Take what he called a 'primary' representation (which, as we have already established, is an image that has truth relations to the outside world). Then make a copy of this primary representation (Leslie calls this copy a 'second-order' representation). Finally, one can then introduce some change to this second-order representation, playing with its truth relationships to the outside world without jeopardising the important truth relationships that the original, primary representation needs to preserve. For Leslie, when you use your imagination, you leave your primary representation untouched (for important evolutionary reasons that we will come onto), but once you have a photocopy of this (as it were), you can do pretty much anything you like with it.

Read the whole thing.

Hat-tip: 3 Quarks Daily.