Today in ubernerd blogging: Bryan Caplan doesn’t buy Robin Hanson’s assertion that growth is not forever.

I’m baffled.  You don’t have to be a sci-fi guy to think that in the next century we’ll get working virtual reality.  And once we have that, why couldn’t economic growth of 1% (or 10%) continue forever in simulations?  In the real world, we can’t all be emperor of an infinite universe.  But I don’t see why every one of us couldn’t preside over our own simulated utopias?
As for all this talk of atoms: Economics is about value, not matter.  As long as people regard vivid virtual goods as acceptable substitutes for actual goods, how can the scarcity of atoms stop everyone from having everything he desires?

I don’t think this is right. In the end even mental states must be represented by states of matter. Thoughts, I believe, have a one-to-one correspondence with configurations of the brain. At some point there must be a limit to our ability to reconfigure brains in new and interesting ways.

We should also recognize that there are a finite number of molecules in our brains. (Actually, I think we can do this with neurons but even if we assume that even re-jiggering minute structures of neurons corresponds to different thoughts). Thus there is a finite number of combinations and configurations of molecules. Thus there are a finite number of thoughts and feelings. At some point we will reach the end.

Now what we are arguing here is that either humanity is reaching the carrying capacity of our region of the universe or that we have maxed out the sum of human potential. Neither of these is likely to actually happen in my opinion.

Much more likely is that human population will drift towards and finally reach extinction long, long before we hit these constraints.  I see relatively near term extinction as highly likely because modern technology is mitigating the reproduction instinct. Obviously birth control plays the major role by allowing sex without reproduction.

The ability to support ourselves with capital investments made during our working lives means that the need for children to support parents in later life is falling. This reduces the need for children.

An ever increasing range of entertainment technology makes perpetual adolescence more attractive.

Put together these factors suggest that we will reach the point were global population is contracting rapidly. Suppose that sometime in the next century global population peaked at 10 Billion and then began to decline at 2% a year. In another 1000 years, humanity would be gone.

I don’t think this is a particularly dark state of affairs, however. These days we mostly focus on the transition costs associated with an aging society, but it is important to remember that the long term effect of a shrinking population is increasing wealth.

I see the last human being on earth as being extremely happy, extremely wealthy people living in a subtropical extended adolescence. They will look and feel 22 until the day that they will die. They will want for nothing material. And they will spend their last days dancing on the beach, blissfully unconcerned about the end of humanity.