A consideration of the miraculous complexity of the clotting cascade is an opportunity to reflect on ‘intelligent design’ as the logic of ignorance: Steve Jones, paraphrasing Darwin, says that Intelligent Design proponents look at an organic being “as a savage looks at a ship, as at something wholly beyond their comprehension”. It reminds me of something a philosopher patient of mine said to me today — “There is no excuse for ignorance, but even less for knowledge without action.”