perfessor multigeek's Journal: "habitable" planets (beta version)

There seems to be a pernicious train of thought popping up in the post-Columbia disaster discussions about the viability of space travel.
It seems to typically go like this:

1-The long-term purpose of space travel is to get us to other places that we can live.

2-We only live on planets.

3-The only planets that are viable are those that are very much like Earth in terms of temperature, atmosphere, gravity, etc.

4-The odds of finding such planets are very low and we have seen none around Proxima/Alpha Centauri.

5-Thereby large scale human space travel has no purpose.

Now every single part of this argument is flawed. But I want to stick to point 3 for now.
It seems to me that our current conventional wisdom about what constitutes a viable planet is much like that of the folks who used to say that humans would die or be emotionally scarred by travelling faster then a horse could carry them.
Look it up. Respected figures opposed the locomotive, the automobile, the airplane, and supersonic flight on the grounds that each in turn was "unnatural" and that humans could only live as we had been accustomed to doing.

Personally, I see no long-term techological barriers to our building two-hundred meter tall domes (well, dome-ish, but we'll get to that later) several kilometers across in clusters of thousands on and within some sub 1-gee planet and having an entirely viable civilization within.
Add to that technology/biology that allows citizens of this far away place to roam the surrounding "hostile" world for several days wearing accoutrements no more obtructive then 1920's office attire and the surrounding regions become settleable.
I'm going to want to go into this at more length in a longer JE soon, but for now, I'm curious; what parameters do you see for a world on which humans could live in an autonomous fashion, with a population of, say, a hundred million people, who grow their own food, run their own industries, and generally think of that world as home?

Rustin

that train of thought

[Em Emalb]

should have derailed years ago.

These are probably the same people that use modern technology directly descended from the Nasa/Space program unthinkingly everyday.

Simpletons will always be around. Filtering them out is a much more viable solution.

Re:that train of thought

[perfessor multigeek]

Generally I agree, which is why I'm not even bothering to respond to most of the fallacies in that set. But it seems to me that the subset of what constitutes a viable permanent environment for a human society contains enough room for honest disagreement between competent people to make discussion and debate useful and fun. So I decided to see where that one might lead.
Rustin