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 only clue. Get the facts!

- Robert A. Heinlein

[Were You Aware?: New Heinlein biography out soon]