Bob asks in response to my temporal autarky posts: "Right now I have $100 I'm trying to decide what to do with. I could invest it, I could spend it on sushi, OR I could wire it to a hungry guy in Africa. Now if that guy in Africa could touch a rock and turn it into a gold bar, then ship it back to me, for sure I would consider that a great trade and I'd do it. By the same token, the guy in Africa would much rather have the stuff he could buy with $100 than the labor it takes him to touch a rock.
Ah but alas, the laws of physics don't allow him to touch a rock and turn it into gold. Hence, I myopically do not take into account the fact that if I just *gave* my $100 to the guy in Africa, he would have more utility.
Did I just spotlight another example of a problem with the laws of physics impoverishing us?"
In a sense, he absolutely did spot another example of the laws of physics impoverishing us. Physics, after all, is the primary source of scarcity in this world and scarcity is impoverishing and the whole motivation for economic action. So sure! Blame the laws of physics.
But this is an odd thing to complain about. Generally economists don't complain about the lack of superpowers as welfare-reducing.
What's different? Bob is really pointing to an infinite production cost imposed by physics. Fair enough, but production technology is usually taken as given (if he wants to make an argument why we should care more about these sorts of limitations, he's welcome to). I'm pointing to an infinite transaction cost imposed by physics. Usually economists take the inability to make transactions to be worthy of more serious consideration than the inability to succeed at alchemy. On top of this infinite transaction cost is an externality: we can impact the future but they can't impact us. This is not all that bad, of course! That's what we call "cause and effect", and we wouldn't be able to understand all that much without it. I'm not cursing the laws of physics here, I'm just trying to understand its implications for human society, and thinking through decisions we might want to make as a result of those implications.
UPDATE: And Facebook tells me it's Bob's birthday today - Happy Birthday Bob!