[nvm0n2]

That's not a great argument by the physicist, the economist definitely won that debate. The physics guy only seems to realize that though when he wakes up the next day and has calmed down a bit.

Although the link is useful for the thermodynamic calculations, there are two major problems with the argument as presented:

1. Right up front the physicist arbitrarily bans space travel. The economist, being an agreeable man who'd probably rather be making smalltalk with a pleasant member of the opposite sex rather than defending his whole profession to a bolshie physicist, accepts this limitation, but he shouldn't have done. Nothing in economics is predicated on a space travel ban. We are already obtaining economic growth from space via satellites and that era has barely got started. None of the physics arguments work if you make the relatively small leap to putting factories, power plants etc on moons, asteroids, space stations or other planets. This doesn't require colonization assuming progress in robotics.

2. Much more seriously, the physicist doesn't understand what growth or wealth mean in an economic context. The economist tries patiently to explain this to him many times, and he just doesn't get it. This is a very common problem when talking about economics because people aren't used to the expansive definition of wealth economists use, so often conflate it with other things like money or (in this case) energy.

You can increase wealth indefinitely even with a stable population and stable energy/resource usage. This isn't controversial or weird, it's just part of how wealth is defined. The VR example is one attempt, dessert another attempt to explain this to him, but he just doesn't get it until the next day when he suddenly has an epiphany but decides it wasn't his fault because he personally distinguishes between "growth" and "development". No such distinction is recognized by actual economists for valid reasons. But you don't get to claim there's a problem with economics just because you failed to understand the lingo of the field.

[dTal]

If that's "wealth", then "wealth" is worthless.

When you have a capped number of humans, and every last one of them is jacked into the Matrix and has everything they could possibly want - what is there left to grow? If the growth in "wealth" doesn't actually reflect an improvement in human experience, then it's a pointless term. Sure you can have two computers trade virtual tokens at an ever-increasing rate until you saturate the network cable, but calling it "wealth" is an exercise in semantic subterfuge.

It's like saying economic growth is unbounded because you can always print more money. Eventually it has to bottom out in something real.

[nvm0n2]

I think you're arguing at cross-purposes with me. Nobody has argued that bouncing virtual tokens around creates wealth. That's the "wealth is money" fallacy that I just criticized.

Wealth as used by economists just means all the goods and services that we provide to one another, sometimes with the addition of "services" like a clean environment. It's very broad and includes things like cultural wealth, and doesn't even have to involve selling something.

That's why printing money doesn't create economic growth and nobody claims otherwise. In fact in the debate they specifically agree to discount inflation to avoid it getting in the way.

[dTal]

The point is that there's no such thing as a (meaningful) good or service that doesn't require some amount of a tangible and finite physical resource - human time, if nothing else.

The economist's position - and yours, apparently - is that "growth", whatever it is, can be sustained literally infinitely, on a finite rock amongst a finite group of hairless apes where nothing about the actual situation is infinite. So you can either have a highly abstract definition of "growth" that allows this to be true, or a definition that most people would recognize as meaningful or positive, but not both.

[nvm0n2]

Be careful here - the economist's position about a finite world was something the physicist picked. The economist agreed to it early on, probably to try and seem agreeable, but it's not a reasonable concession to make. Space exists, we put things there today, presumably will put more things there in future. So there is no finite world.

But let's make the same assumption for a moment. For economic growth [of wealth] to stop requires two things to stop: population growth and productivity growth. As GDP is roughly population * productivity.

Clearly, populations can stop growing or shrink. We can also assume a finite population limit. So this is an argument that productivity growth is also finite. But, why should that be the case? Take the example of computers. Modern computers are much more productivity enhancing than older computers, but they are also smaller (i.e. less physical resources needed) and more energy efficient. Even if the Earth had reached carrying capacity, smarter chips would continue to be designed and the productivity boost of computers would keep increasing. That's just one example, there are many others.

But again, the finite world assumption doesn't hold. So the whole debate is a bit of ivory tower silliness anyway.

[dTal]

1) Space doesn't help you, it only postpones the inevitable. Eventually the ravenous maw of your exponentially growing civilization will run out of stars to harvest, trapped as it is inside a light bubble growing at 1c, its volume expanding with mere cubic growth.

2) You've just relabeled the discussion from "wealth" to "productivity". In any case, scoring some efficiency wins here and there is once again a game with physics-imposed limits.

I repeat my question: when all humans are fully fed, housed, maximally entertained and satiated, every dopamine receptor firing on all cylinders - and you can't make more humans - what exactly is there left to grow? At all, let alone exponentially?

I confess I find the notion of infinite exponential growth of anything, let alone things humans value, so patently and obviously physically unsustainable that I am deeply perturbed by these earnest efforts to defend it. I engage in the spirit one might engage Flat Eartherism, as an intellectual exercise in probing the manifestly absurd - except that this dogma apparently pervades mainstream economic thought, an observation that should terrify anyone who wants civilization to survive.

[nvm0n2]

Yes, very good. If we go hard sci-fi and talk about actually running out of stars in the universe, then I can just counter with some claim that by then we'll all have become inter-dimensional beings, or we'll never exhaust the stars before the next big bang, or that we'll discover that the universe is actually infinite somehow.

When the pair of people in the article were talking about space they meant within the realm of reasonable projection. If your rebuttal to economics is that the field hasn't considered what happens when humanity runs out of galaxies to colonize they'll just chuckle and happily concede the point, because if that's your strongest criticism then for all practical purposes they've won (people will still listen to them because the point you're making is irrelevant in practice).

That's especially true if you make absurd arguments like the survival of the world being at stake because economists don't constantly caveat all their papers with footnotes saying it doesn't apply if humanity reaches the end of the universe. That's itself incredibly silly flat-earther levels of dialogue.

> You've just relabeled the discussion from "wealth" to "productivity".

No I haven't, but this whole thread is sort of proving the point that the term wealth is quite confusing to a lot of people.

We've already seen the economic definition of wealth. How can we obtain more wealth? Because wealth is just everything we do for each other summed up, the most obvious way is to add more people. But people don't work alone, we can increase our output by deploying technology and ideas. Economists call the output scaling of a person "productivity" and it's more or less a function of how much tech that person has access to. A farmer with a tractor is more productive than one with access to only a hoe. Culture and ideas are also a factor but it's mostly tech.

So wealth and productivity (and population size) are deeply related. One is the multiple of the other two:

Wealth = population x productivity

Assume a stable population. Then you are asserting there are limits to productivity due to physics. That may be so, but again, if those limits are hit in 50,000 years then nobody cares.