> Yes, it's intangible but consider this; go back 2 centuries and ask someone if they could setup a business concern which produced millions of widgets a year.

To go off on a tangent: two centuries ago was the height of the first industrial revolution (at least in Britain). The first time in history when this actually became realistic.

The Industrial Revolution was the first time we had sustained, broad based productivity growth year after year (even if only around 1%, which is quite low by modern standards).

Weirdly enough, we can see sustained productivity growth in artillery and guns long before the wider industry.

Another weird connection: sometimes people look at a toy 'steam engine' that the ancient Romans had access to (https://en.wikipedia.org/wiki/Aeolipile) and wonder if they could have had an industrial revolution. But, to make a proper steam engine you need a lot more than just the right idea. You need a lot of metallurgy and precise crafting.

Specifically one thing you need is precision crafted cylinders that gas can expand in to move a piston. Well, at the time of the Industrial Revolution, European nations had just spent several hundred years locked in existential competition over who can make precision crafted cylinders that gas can expand in to move a bullet.

That is interesting.

I wonder though, if not it would have been possible to build stationary steam engines with Roman tech using oversized bronze castings for cylinders. Perhaps set in bedrock to give extra strength.

Weirdly though, electric generators in watermills would have been much more attainable - except nobody had any understanding of electricity.