Absolute limits: running out of stuff

Robin Hanson is an economist at George Mason University who likes to push the bounds of discourse.  At times he finds a useful hammer, and all our problems become nails.  But we all tend have our favorite overworked tools – mine is a battery drill.

He is the origination point of my old cannibalism posts. Not too many economists will address the economics of cannibalism.

Here he addresses the limits of growth.  But rather than complain about the impracticalities of exponential growth, he goes directly to the heart of the matter.  When you run of stuff – all the stuff in the galaxy to be exact – you cannot have growth.

The End of Possibility

Robin Hanson, Overcoming Bias, 16 October 2011.

Once upon a time, down on the farm, ordinary lives had few options. Only a few neighbors were available as friends or lovers, only a few careers were possible, and most careers had rather predictable daily schedules… By contrast, cities, travel, and even war offered many exciting possibilities. Fiction celebrated these things, and fiction itself offered even more possible experiences…

[E]ndless expanding possibility seems central to our modern view. We all “know” that new techs expand our possibilities, and an endless series of new techs lie ahead, each more unpredictable than the last. Science fiction emphasizes a blizzard of strange futures, from which most folks take the lesson that the future is so unpredictable that there is little point thinking about it. Most think we can’t even count on basic physics, as new paradigms could change everything…

But in the long run, this faith in endless possibility is completely wrong…

Yes, our physics isn’t the last word, for but for most practical purposes it is damn close. New physics will only make a difference in incredibly unusual cases. Our understanding of basic economics is also hardly the last word, but we still understand enough for it to give useful insights into future societies.

In an earlier post of his, he further elaborated:

This is the Dream Time

Robin Hanson, Overcoming Bias, 28 September 2011

Per-capita wealth has only been rising lately because income has grown faster than population. But if income only doubled every century, in a million years that would be a factor of 10³⁰⁰⁰, which seems impossible to achieve with only the 10⁷⁰ atoms of our galaxy available by then.

Note that to some degree you can argue that there are more possibilities than there are discreet units.  That is why there are more stock mutual funds than there are actual types of stocks to purchase- although not more than there are actual shares of stocks.

But at the point where your model requires a larger growth factor than there are atoms in the galaxy, you are likely starting to run into problems.  And if you are saying – “We will go to other galaxies – he has thought of that. The short answer- if there was not a hard limit on inter-galactic travel, the aliens would already be here.  He answers some (foolish in my mind) critics in an enjoyably esoteric piece – here.