What are the facts? Again and again and again – what are the facts? Shun wishful thinking, ignore divine revelation, forget what ‘the stars foretell’, avoid opinion, care not what the neighbors think, never mind the unguessable ‘verdict of history’ – what are the facts, and to how many decimal places? You pilot always into an unknown future; facts are your single clue. Get the facts!
– Robert A. Heinlein