I think that is taking an overly optimistic view of the past. No other time in history has it been easier or cheaper to pick up your life and move and the truth is that almost anywhere in the "west" provides better living conditions and less persecution than anyone from even a few generations back could hope to receive.

I think you're forgetting that there are dreamers, crazies and malcontents that historically have been more than willing to risk everything to make a go somewhere new or get away from their civilized peers.

Persecution is certainly one motivator, but hardly the only one. Some people are driven to explore, some are religious nuts looking for whatever they look for, some just hate civilization or people or their family or whatever, some can't explain their motives.

Civilization isn't for everyone.

Just because there are people willing to risk more doesn't change the fact that you can do almost the same thing today and risk less. All most westerners would need is a few thousand dollars, a passport, and a few weeks time and they can make it to almost any land in the world. There might not be any free land to claim and start your own country, but even in the US there are still large swaths of ungoverned land that an off the grid type could set up to live their life in peace with little interference from civilization.

These debates always end up with people talking past each other. One side will say that present living conditions are better than they ever were in the past. The other will say that past frontiers provided freedoms and opportunities that aren't available today. Both these things are true -- you are talking about different things.

IIUC you're saying someone would have a better chance escaping to Mars to enjoy their political freedom rather than, say, a mountain community in the U.S.

I don't think that follows. The forces that exert a stranglehold on terrestrial freedom-seekers will exert 10x the grip on territories where the resources required to contain dissidence are greater than terrestrially. If they won't let people run around in the Ozarks with machine guns, they sure won't let them on spacecraft in a fragile space colony.

The simple fact that an extraterrestrial colony requires more resources than a terrestrial one implies there will be limited freedom there. At least until the planet is somehow liberated from excessive control. But I don't see how that will happen until thousands of planets are available to the point that Authority can abandon a planet...

...or until a "Space-Columbus" is able to colonize another planet without the control of a terrestrial force or until another planet is able to liberate itself from Earthlings. That will take a while, but I guess you have to start somewhere and maybe SpaceX is it. :)

One of the things that makes frontier colonies interesting is they can be selective in who they bring along. This can make control moot, since everyone in the colony agrees on most things anyway. But it can also, conceivably, be problematic.

Why not the oceans? Much easier to populate than Mars.

You would enjoy this game: https://en.wikipedia.org/wiki/BioShock

Does that protect people from the event of a major nuclear war?

Would it be immune to accelerated climate change on Earth?

availability of land isnt the only factor here.

(i dont actually know the answer to these questions, and obviously it would likely depend on the details of this water habitat)

If you're trying to escape climate change making a place uninhabitable for humans, you probably don't want to aim for Mars.

I'd take living on an Earth ravaged by nuclear war and global warming over Mars any day, to be honest.

The answer to your first question is yes. Water is incredibly effective at shielding radiation - https://what-if.xkcd.com/29/

>Does that protect people from the event of a major nuclear war?

In the distant future, Mars may not necessarily afford protection either.

It's going to be sad if the doctrine of mutually-assured destruction some day applies within a multi-planetary context.

Most likely this would take the form of national territories being established on Mars by existing nuclear powers, the weapons either being imported or fabricated on-site.

Of course, the wierder scenario is one where advancements in propulsion technology allow for faster and cheaper delivery of payloads to Mars, resulting in some sort of Earth-to-Mars nuclear strike capability. Transit may remain quite latent, but it could still do the job. Imagine having weeks or months to contemplate an incoming nuclear attack.

What makes you think Mars would be more liveable than Antartica after a nuclear war or accelerated climate change?

In the event of a major nuclear war, living in Antarctica won't protect you from environmental radiation, which will be at highly elevated levels for decades throughout the entire planet.

And how do you protect yourself from radiation on Mars, given its thin atmosphere and lack of magnetic field?

Mars's thin atmosphere does provide significant levels of radiation shielding, such that surface radiation levels are comparable to those in low-Earth orbit:

http://www.space.com/18504-mars-rover-curiosity-astronaut-ra...

The Moon, on the other hand, is baldly exposed:

https://science.nasa.gov/science-news/science-at-nasa/2005/0...

Earth's oceans span twice Mars's entire surface, too. Lots of room!

He did kind of address this by saying "being multi-planetary is good in case of apocalyptic event"... it's about having an offsite backup.

This video (wanderers) does not give a reason, but it sums up quite nicely the way I feel it: https://youtu.be/YH3c1QZzRK4

What if the goal is actually to get away from the rest of humanity (in particular the part of it that would be likely think that colonising Mars is a ridiculous waste of money)? The circumstance that people of most political persuasions except for a very narrow set tend to find moving to Mars ridiculous but moving under the sea realistic itself seems to be pretty good evidence that if you wanted to get away from everyone outside of the narrow set, going to Mars would be good enough but going undersea would not.