Steam engines happen when it’s steam engine time: a process almost mystical, almost teleological, because it exists outside the scope of our framework for understanding historical progress. The set of things that had to come together for this particular invention to occur includes so many thoughts and events we could not think or know about that its appearance is like that of a new star: magical and previously unthinkable. But the history of science shows us that all invention is simultaneous and multiauthored.
