Facts. What are the facts. Again, and again, ask yourself, what are the facts.
Shun wishful thinking, ignore divine revelation, forget what the stars foretell. Avoid opinions, care not what the neighbours think, never mind the unguessable, or ‘Verdict of History‘ —ask, what are the facts, and to how many decimal places.
You pilot always into the unknown future, facts are your single clue. Get the facts!
— Robert A. Heinlein