Some inventions obviously depended on a breakthrough discovery, such as a new scientific theory, and were developed not too long after that theory. The telegraph, for instance, was invented very soon after the physical theory of electromagnetism was worked out. Other inventions were dreamed up long before the underlying technologies were possible, such as da Vinci’s helicopter or Babbage’s computer—ideas ahead of their time.
But some inventions seem to have come along much later than they were possible, raising the question: why wasn’t this invented much earlier? Alex Tabbarok calls these “ideas behind their time”.
This page collects analyses and hypotheses about such ideas. (Inclusion here does not imply endorsement of the analysis.)
“Why it took so long to invent the wheel”, in Scientific American. It’s not the wheel but the axle and the friction on it; may have required metal tools and carpentry techniques.
“Why was the Aeolipile not put to practical use in classical antiquity?” on History StackExchange. The aeolipile, also known as “Hero’s engine”, was a sort of primitive steam turbine. Multiple answers here, some focusing on demand, others (which I find more compelling) pointing out that the aeolipile doesn’t produce much torque and is inefficient.
“Why did we wait so long for the bicycle?”, by me. Design iteration, materials and manufacturing technology, possibly the need for a leisure class to form the market for it, and other economic and cultural factors. Note that since I wrote this, commenters have stressed the manufacturing issues and suggested that those should be given more weight. In particular, Nick Szabo has pointed out the importance of bearings to reduce friction; even the first prototype of the bicycle, while made mostly of wood, apparently used brass bearings.
The flying shuttle is addressed towards the end of “Is Innovation in Human Nature?”, by Anton Howes. Concludes there was no technological, economic, legal or social barrier to the flying shuttle before its invention in 1733.
Could bolt-action rifles have been produced in the 1700s or 1800s? Reddit discusses.
“Where be dragons?”, by Anton Howes, asks why role-playing games such as Dungeons & Dragons weren’t invented until the 20th century. Like the flying shuttle, it seems there were no hard barriers to it happening much earlier, although some soft ones (social/cultural) are proposed.
Examples that could use more thorough/convincing analyses:
“Humans domesticated horses in ~4500 BC, but stirrups were not invented anywhere until like ~200BC (4300yrs), and did not show up in Europe until the Middle Ages (from central Asia)” (@atroyn)
Wheeled luggage. Everyone likes to bring this one up
Send me links to more articles like this (email@example.com); I’ll update this page from time to time.