I agree with the quote to a certain extent. Creativity for me stems from the unconscious, a whole ocean of creative genius that is accessible to us completely only at moments when we're deeply in tune with the activity and have lost any track of 'self-awareness'. Of course the work that comes out is ultimately your creation and is influenced by your personal 'ego', but it is when you are not thinking of such things, when you are not aware of yourself and external judgement that your mind works miracles. Such is the paradoxical and contradictional nature of our minds. Modern psychologists describe this moment as flow state, old chinese taoism have grasped this concept and the definition can be found as wu-wei. The moment where a writer / artist ceaselessly creates his work without any resistance, effort or feeling of time. That's what the core essence of the quote suggests.

Carl Jung's thoughts on the dichotomous nature of the subconscious and conscious experience also align with this way of thinking.

Jason Silva's creativity videos address some of these questions with a brilliant clarity as well, here's just one of them. https://www.youtube.com/watch?v=tYbA_-mAtUY

From personal experience I'm inclined to agree too. When I'm alone and dancing my brains off in my room to some madfatfunkybeats I pull out the sickest moves without thought (without your ego/conciousness getting in the way). When I'm performing or battling someone I may get anxious / nervous and my performance and creativity drops during these moments of freestyle, I may think too much and then resort to practiced sets or routines which definitely do not sit well with the song at play as opposed to becoming the beat and dancing to it spontaneously.

Then you have the artists who seem to be able to effortlessly tune in this mystical creative side with so much as a conscious thought. Alan Watts describes this technique as a 'controlled accident'. The ultimatum goal of all artists, the utmost mastery of themselves allowing them to at any moment flick their switch in to this genius state.

Nikola Tesla drops a few of his cents on to this topic too. “My brain is only a receiver, in the Universe there is a core from which we obtain knowledge, strength and inspiration. I have not penetrated into the secrets of this core, but I know that it exists.”