What does an artist see that others do not?

I was on facebook today and I came across a post by ArtistNetwork. They asked: "As an artist, what do you notice that others don't?"  

I read some of the answers and they made sense to me. They mentioned light, shadows and things like that. I started to think about it and I gave my answer. However, I couldn't stop thinking about it. Then I thought, what if Leonardo isn't talking about seeing shadows, light or even nature but seeing the truth in himself?
When I responded to the facebook post, I tried to think of my own personal struggles while learning how to be an artist. I hope you understand that I don't think that my answer is better than anyone elses of course. It was just from my own personal experience. What I said was, "it takes a lot of patients & courage among other things to be an artist... even very talented artist have a hard time with it. But to keep pushing fwd, to keep learning and wanting... i think that is where a true artist sets him/herself apart from others. But, that is not the truth, just my thoughts!" 
After I wrote that, I wondered if that is what Leonardo was talking about. Was he talking about the artist seeing the truth in himself as well as in art? To tell the truth, I haven't read that quote in its original context. I probably should and then maybe I would know but I am glad it took me to that thought. 
Just something to think about...