Imagination gives you the picture. Vision gives you the impulse to make the picture your own.”
-- Robert Collier
"I never truly know what the painting will look like or how it will turn out. I can have an idea and a hope, but the only thing I am certain of, is that I must paint it." This is an example of contemplation of your art.
Does an artist know that a painting will be a masterpiece before he even puts the brush to canvas, or is he only sure that he must make that first stroke? And who decides that a painting is a masterpiece anyway?
Perhaps there are appropriate times to act from certainty, like there are appropriate times to act from love, pride or courage...and then there are those times when it is best to have these feelings and definitely not act from them. The key is learning to tell the difference.