This is always a hot topic on HN. My takeaway from all of the discussions is that the ability to 'see' an imagined visual representation of something exists on

This is always a hot topic on HN. My takeaway from all of the discussions is that the ability to 'see' an imagined visual representation of something exists on a spectrum from absolutely nothing ever, into a minds eye abstract idea of an image (like a melody heard in your mind rather than your ears) toward a full ability to see an image overlay in the visual space. There's a lot of debate as to whether this is a trainable ability.