William James (1842-1910)
Act as if what you do makes a difference. It does.
This assumes, of course, that one is actually doing something - not just talking about doing something, talking about what others should be doing, or reacting to events, i.e., complaining about what others have done.
I like Wm. James. He's the same guy who refuted scepticism (and promoted 'faith') by saying:
Dupery for dupery, what proof is there that dupery through hope is so much worse than dupery through fear?
I wonder what he would make of the "believe" campaign. . . .