I still don’t see how the argument is weakened by the existence of robots, but I agree it is left pretty weak.
No, it’s weakened by a variant of the conjunction fallacy, as it were. If you previously argued ‘A ~> C’ but have now changed your argument to ‘A & B ~> C’, then probablistically C has gotten less likely.
So one originally starts off arguing ‘we may have elevators soon, since when we can create miles of nanotubes, then we can create space elevators quickly’, and changes it to ‘we may have elevators soon, since when we can create miles of nanotubes and we have also finally developed space robots to go synthesize it in orbit for us, then we can can create space elevators quickly’.
You have narrowed the possible routes to creating a space elevator by ruling out routes that don’t involve von Neumann machines; that ought to reduce our probability.
Ah! I’ve got it now. The assumption that bots are available doesn’t weaken the case for an early elevator. The assumption that bots are necessary does weaken the case.
I don’t know why it took me so long to pick up on that. Sorry.
No problem. I wasn’t sure I was being fair in inferring that the bots were necessary. If they aren’t necessary, then by the same exact logic, our probability ought to go up - ‘A v B ~> C’ is stronger than ‘A ~> C’. (The more independent pathways to a result, the more likely one will work within a certain time span.)
No, it’s weakened by a variant of the conjunction fallacy, as it were. If you previously argued ‘A ~> C’ but have now changed your argument to ‘A & B ~> C’, then probablistically C has gotten less likely.
So one originally starts off arguing ‘we may have elevators soon, since when we can create miles of nanotubes, then we can create space elevators quickly’, and changes it to ‘we may have elevators soon, since when we can create miles of nanotubes and we have also finally developed space robots to go synthesize it in orbit for us, then we can can create space elevators quickly’.
You have narrowed the possible routes to creating a space elevator by ruling out routes that don’t involve von Neumann machines; that ought to reduce our probability.
Ah! I’ve got it now. The assumption that bots are available doesn’t weaken the case for an early elevator. The assumption that bots are necessary does weaken the case.
I don’t know why it took me so long to pick up on that. Sorry.
No problem. I wasn’t sure I was being fair in inferring that the bots were necessary. If they aren’t necessary, then by the same exact logic, our probability ought to go up - ‘A v B ~> C’ is stronger than ‘A ~> C’. (The more independent pathways to a result, the more likely one will work within a certain time span.)