So then the next question is: why was precision engineering not developed earlier? One apparently plausible answer is that the perceived need did not arise earlier, but that leads into the question of what changed that perception? If the answer is "the development of the steam engine", we have a causal loop which is not clearly anchored to any particular time.

One of the often-overlooked prerequisites for Watt's improvement of the steam engine through the use of an external condenser was the need for a precision cylinder. Then-recent advances in boring machinery for making cannons provided the means, but cannons had been around for centuries before this development came about. Furthermore, while this improvement depended on an advance in precision engineering, Newcomen's steam engine was already eighty years old.

The industrial revolution and its successors depended on the mutually-supporting bootstrapping of several disparate facets of technology, all of which could possibly have started earlier, so it seems unlikely that the timing of the initial spark can be attributed to an until-then absence of just one of them.