[TimGebhardt]

Summary: Author hopes we don't find life on Mars because if it's dead that provides an ill omen for the human race. He thinks if life on Mars wasn't sustainable then he repeats the whole argument that there must be some reason why advanced civilizations can't manage to get off the original rock they're assigned to and that's why we haven't seen any other intelligent life.

[trendspotter]

Nick Bostrom's reasoning is more complex, but yes, you nailed the summary perfectly. Even shorter: The more complex life on Mars we are going to find, the more we as human race are doomed, says Bostrom. Because as Bostrom wrote in TimGebhardt words: "there must be some reason why advanced civilizations can't manage to get off the original rock they're assigned to" and if there is life on Mars, it could be everywhere in the universe. Nick Bostrom's reasoning: If life could start everywhere else, why haven't we detected it, yet. I think Nick Bostrom should have focused more on the time and randomness factor. Maybe there was life in our galaxy, but they visited us before humans have lived. Or we have been visited (think peruvian desert drawings), but before we as human race were as advanced as we are today and they left our boring planet to visit another galaxy. There are probably more than 170 billion (1.7 × 1011) galaxies...

[berntb]

If the Orion project in the 1960s hadn't been stopped, we might have viable interplanetary colonies already. Also, if NASA hadn't poured most money into the shuttle (and hence had a reason to kill competing projects, for job security) the space exploration/colonization would be much further along.

Even now, we might be less than 50 years from independent colonies, if lower costs for space launch finally "take off" with Musk.

This implies that if there is some common reason (e.g. a physics experiment with unexpected outcome) that exterminates budding civilizations, it ought to have already happened (and we were lucky) -- or it is something big enough to blast a whole solar system.

Edit: It would be interesting with percentage chance evaluation of the possibility that the Shuttle project doomed humanity to extinction...?

[kalms]

Which in itself is a bit weird. Mars and Earth formed in the same solar system, from an orbital disk around the same sun. Similar conditions and building blocks.

Surely whatever improbability would be diminished because of this?

[khafra]

The probabilistic evidence is a bit more indirect, and depends on anthropics:

Since we don't see galaxy-spanning, highly advanced civilizations, there seems to be some combination of factors that prevents planet-bound dirt from turning into them. If those factors are primarily after our stage of development between dirt and galactic civilization, that's Very Bad News, because we shouldn't expect to get extraordinarily lucky. If those factors are primarily before our stage of development, that's reasonably good news, because we've already made it past the hard part.

Seeing bacteria isn't as bad as seeing the ruins of a civilization just past our stage of development. But it does move the probability-mass forward more than if we just found dirt.

[kalms]

There's so many things that can go wrong, during the period needed for advanced intelligent life to evolve. Add to that the inherent difficulty of moving between solar systems. Space is vast, and we're not really making that much noise. I don't see a big paradox here?