Live players are in creative communion with reality: processing feedback, learning, and adapting to circumstances. In Samo's definition, they're able to do new things. Dead players are repeating stereotyped behaviors, often cargo-culting what live players have pioneered.
One sure-fire way to tell that someone's alive is when they surprise you. I think this explains a lot of the appeal of artists. Even if their art isn't particularly compelling, at least they're making things that have never been made before. At least they're showing signs of life