Right, but he's also expressed scepticism that you could produce arbitrarily high value per atom. Ah, found the link and it was in the context of the number of people-equivalents worth of value we could produce per atom:

It seems just physically impossible to create 10^140 or more lives we would value like ours per atom, even considering quantum computing and black hole negentropy. But could individual living standards be that high?

To say that someone had a standard of living 10^140 times a subsistence level means that 10^-140 of their income could buy a subsistence level standard of living. Someone with a subsistence level living standard, and a square root type risk-aversion, would reject an offer to jump to today’s world average living standard, twenty times higher, if they could instead roll 69 ten-sided dice, and only get to jump to this 10^140 higher standard if all the dice came up 1. (Someone with a fourth root risk aversion would prefer to roll 35 dies.) That is just how incredibly fantastic this 10^140 higher living standard would be. A living standard 10^2950 higher is far far more fantastic.

I find myself somewhat confused then, because my recollection is that he has consistently argued that economic growth will not be able to continue indefinitely, and that from some point in the future for the vast remaining part of human history we will be living in a static society.