He did not "say exactly opposite". He said: it'll be at least 100 years before we have much chance of mitigating species-level disasters by putting part of our species somewhere other than earth, so "we have to be very careful".
My goal is to point out that you are misrepresenting what Hawking said.
If colonies will be built by national states
If these are genuinely self-supporting colonies on another planet, I think it will not be long -- a few generations at most -- before they stop thinking of themselves as mere offshoots of whatever nation back on earth originally produced them. Their relations with other colonies on Mars (or wherever) will be more important to them than their relations with anyone back on earth. And I do not think they will be keen to engage in mutually assured destruction merely because their alleged masters back on earth tell them to.
(And if they are not genuinely self-supporting colonies, then they are not what Hawking was talking about.)
My criticism should concentrate on two levels: on his wording and on his model of x-risks and their prevention. His wording is ambiguous than he speak about tens of thousand years - we don't have them.
But I also think that his claims that we have 100 years (with small probability of extinction) and that space colonies are our best chance are both false.
Firstly, because we need strong AI and nanotech to create really self-sustained colony. Self-replicting robots are the best way to build colonies. So we need to prevent risks of AI and nanotech before we cr...
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