Robbie, given your comments on this subject you might enjoy the following two talks/books.
In his book Mastery, Robert Greene discusses how masters in a field are capable of combining the fluidity of a child’s mind with the accumulated knowledge of a more developed mind (AKA finding the sweet spot) to produce creative insights. Alternatively, you can check out his talk on YouTube.
The next talk/book isn’t as directly related, but Beau Lotto talks about the subject of “creative” solutions from a neuroscientific perspective in his book “Deviate”, and elaborates on the fact that our internal solution-space is shaped by our assumptions. He also argues that the best way to have “creative” ideas is to develop an high-dimensional solution-space.
Arguably, finding an idea for a startup is a creative insight.