The point can be made more general: surveys of hundreds of significant new technologies show that almost all of them are invented simultaneously or nearly simultaneously by two or more teams working independently of each other. Invention appears in significant part to be a social, not an individual, phenomenon. Inventors build on the work of those who came before, and new ideas are often “in the air,” or result from changes in market demand or the availability of new or cheaper starting materials. And in the few circumstances where that is not true – where inventions truly are “singletons” – it is often because of an accident or error in the experiment rather than a conscious effort to invent.