brumguvnor

Hmmm: very true.

My thought experiment was more along the lines of if we have a true Dark Age of a few centuries - long enough for most of the metal extant in our infrastructure to decay: given that - I cannot see anyone raising themselves much beyond "advanced agrarian" levels: Roman Empire kind of sophistication.

And without oil I would think any industrial ciivilization is doomed to be stillborn: it's energy density, portability and stability are unrivalled: if I remember correctly, England pretty much deforested itself at the start of the industrial revolution, trying to run a steam engine economy on wood alone.

The upshot of all this being: if we cock it up then that's it: no more industrial civilization for Earth.

I'm typing this on a tablet - which is resting a a copy of your book!

What do you think of the thesis that industrial civilisations are once only events per planet? That should there ever be a disaster that knocks us back to the Stone Age that it would then be impossible to booststrap ourselves through another industrial revolution because all of the fossil fuel and metal ores would haven been mined out already, and without them as an intermediate stage you cannot get to printed circuits, satellites or renewable energy?