[hebdo]

The point was that exponential growth is probably impossible, not just any growth.

The most serious objection to the propositions in the article is refuted at the beginning, when they agree that our future will be tied to one planet - "I assume you’re happy to confine our conversation to Earth". There are good reasons to expect that this will be invalidated somewhen in the next 400 years.

[dredmorbius]

"There are good reasons to expect that this will be invalidated somewhen in the next 400 years."

Citation required.

There are awfully good reasons to believe it won't.

https://xkcd.com/1389/

Even people whose job it is to be optimistic about space and science aren't.

Charlie Stross:

http://www.antipope.org/charlie/blog-static/2007/06/the-high...

"I write SF for a living. Possibly because of this, folks seem to think I ought to be an enthusiastic proponent of space exploration and space colonization. Space exploration? Yep, that's a fair cop — I'm all in favour of advancing the scientific enterprise. But actual space colonisation is another matter entirely, and those of a sensitive (or optimistic) disposition might want to stop reading right now ..."

http://www.space.com/29862-kim-stanley-robinson-aurora-inter...

Kim Stanley Robinson on interstellar / interplanetary colonisation:

"Q: What about interstellar colonization, in particular?"

"A: There are a lot of people, even powerful, influential people, who seem to think that the goal of humanity is to spread itself. I want this book to make people think really hard about — maybe there's only one planet where humanity can do well, and we're already on it."

[mirimir]

OK, but let's say that value isn't related in any fixed way to material or energy inputs. It's based only on market forces. In that case, why is exponential growth in value not possible?

[dredmorbius]

What exactly is it that you're "valuing" here?

What's it tied to?

How does it grow without some real, resource-based, basis?

What evidence do you have for such a thing existing?

How about evidence that it cannot? What would falsify your premise?

[tonyedgecombe]

"There are good reasons to expect that this will be invalidated somewhere in the next 400 years."

I keep hearing this but I'm very doubtful we could or even should do it.

[npunt]

Yeah I'm not buying the argument. Whether or not we may one day do so, we're talking huge timescales here [1] where we'll be effectively in steady state. Not to mention the insanity of having our economic theory based on this hail mary.

Since the use of economic theory is in guiding our long-term decision making, I'd rather that theory be focused on getting it right with what we have, and be pleasantly surprised if we get a bit more growth from a distant space rock, rather than being reliant on the never ending (and growing) series of space rocks.

[1] Few space rocks besides Mars are particularly habitable, each subsequent one we chase after will be less so, and after that we're going outside the solar system where timescales are massive. Our best knowledge of physics/engineering today is that we can colonize these things, but our best knowledge is not that we can reach them at anywhere near FTL.

[ef4]

The biggest barrier to doing interesting industrial stuff in space is the energies required.

But the whole context of this discussion is a society that has thousands of times more energy available than we do today. That's why it's not at all unreasonable to include space in the discussion. It's hardly fair to posit advanced technology that decreases the cost of energy by a factor of a many thousands while claiming that dropping the cost of space transport by a mere factor of 100 is unreasonable.

No new physics is required. We already know how to build lasers that could lift cargo into orbit -- it's just a question of energy cost.

Habitability is irrelevant: space is for robots. We already know that population growth will level off in only a few decades, so "more people" is not the problem -- it's "more industry". The industry doesn't need to be where the people are -- not when our robots are already good and getting better very fast.