How does Napoleon assert he is the source of his own authority?

Napoleon crowned himself Emperor, people informed he snatched the crown from the Pope Pius VI's hands around 1804 repudiating that authority.

He also had famous quotes such as: "administrer est le fait d'un seul" (la autoridad is the fact of one alone); "Man achieves in life only by commanding the capabilities nature has given him, or by creating them within himself" and "power is founded upon opinion".