Painting what you see vs what you know

I had a conversation with a student during the last workshop. He said he had taken a workshop with a well known artist who is a proponent of painting what you know instead of what you see. And while I agree with that sentiment, it's what makes one artist different from another and leads to the individual interpretation and voice of the artist, it's based on already having the fundamentals down. This artist can say this because he had already invested the time into learning the basics. I'll use the analogy of playing a guitar. You have to take the time to learn where all the notes are and how to strum and pick before you can play what you know, what is in your heart and mind. Likewise with painting, you need to invest your 10,000 hours as Malcolm Gladwell puts it in the book "The Outliers", before you can put the notes exactly where you want them. When we learn to first paint what we see, we are learning drawing, value, color and paint handling. Once these things are ingrained and inherent you, as an artist, are free to have your way with your painting. That's why you have to do 100 (or 300 as Carl Rungius once said) bad paintings before you can get to the good ones.