What Counts as an Invention

[A] Histories of technology are organised around names, and the arrangement is hard to defend once the archives are opened. [B] What emerges again and again is not a solitary insight but a crowd: two or three workers, sometimes a dozen, arriving at much the same device within a few years of one another, usually without contact. [C] The explanation is that an invention becomes possible before it becomes actual. A device waits on its materials, on a market able to pay for it, and on a body of technique assembled from elsewhere; once those exist, several competent people see the same opening. [D]

This is not an argument that individuals do not matter, and the stronger version of it fails on its own evidence. Simultaneous inventions are rarely identical. They differ in what their makers thought the device was for, and those differences decide which version is manufactured, which is patented and which survives to be improved. The patent record makes the point, since it is a record of claims rather than of ideas, and a claim is drafted by somebody with a particular use in mind. What the crowded archive undermines is not the inventor but the moment: the date on which a thing was invented is a legal fact about a document, and only rarely a fact about knowledge.