I tend to think of imagination as a third eye if you will.

It allows us to see what may not yet exist. 

Einstein claimed that imagination was more important than knowledge.

Of course, they both have their place.

However, what raw materials would imagination have to work with if there was no knowledge preceding it?

I think a parallel exists with music. In order to improvise, the musician must first master the basics of his instrument and the mathematics of music.