At the present time, colonising other plants probably would not increase the chance of UFAI, because we will probably develop AI before colonized planets would develop to the point of competing with Earth in R&D.
Another good reason why number of colonized planets is irrelevant. If you agree with me about that then why did you mention it?
It means that all "UFAI" outcomes are considered equivalent. Instead of asking what the real utility function is, you just make these two categories, FAI and UFAI, and say "UFAI bad", and thus don't have to answer detailed questions about what specifically is bad, and how bad it is.
Assigning one utility value to all UFAI outcomes is obviously stupid, which is why I don't think anyone does it (please stop strawmanning). What some people (including myself) do assume is that at their state of knowledge they have no way of telling which UFAI projects will work out better than others so they give them all the same *expected" utility.
You claim that this is a mistake, and that it has lead to the disturbing conclusions you reach. I cannot see how assuming more than one UFAI possibility has any effect on your argument, since any of the policies you suggest could still be 'justified' on the grounds of avoiding the worst kind of UFAI. There are plenty of mistakes in your whole argument, no need to assume the existence of another one.
Also, your statement is not correct. When someone says "a utility function is unchanged by affine transformations", what they mean is that the outcome of a decision process using that utility function will be the same.
I am aware that that is what it means. Since the only purpose of utility functions is to determine the outcomes of decision processes to say an outcome is assigned "zero utility" without giving any other points on the utility function is to make a meaningless statement.
And that is not true if we define zero utility as "that utility level at which I am indifferent to life." An outcome leading to utility epsilon for eternity has infinite utility. An outcome leading to utility minus epsilon means it is better to destroy ourselves, or the universe.
You and I seem to be using different domains for our utility functions. Whereas yours is computed over instants of time mine is computed over outcomes. I may be biased here but I think mine is better on the grounds of not leading to infinities (which tend to screw up expected utility calculations).
If you assume FOOM is the only possible outcome. See the long debate between Eliezer & Robin.
I have seen it, and I agree that it is an interesting question with no obvious answer. However, since UFAI is not really much of a danger unless FOOM is possible, your whole post is only really relevant to FOOM scenarios.
Having all known life on Earth concentrated on a single planet is an existential risk. So we should try to spread out, right? As soon as possible?
Yet, if we had advanced civilizations on two planets, that would be two places for unfriendly AI to originate. If, as many people here believe, a single failed trial ruins the universe, you want to have as few places trying it as possible. So you don't want any space colonization until after AI is developed.
If we apply that logic to countries, you would want as few industrialized nations as possible until AAI (After AI). So instead of trying to help Africa, India, China, and the Middle East develop, you should be trying to suppress them. In fact, if you really believed the calculations I commonly see used in these circles about the probability of unfriendly AI and its consequences, you should be trying to exterminate human life outside of your developed country of choice. Failing to would be immoral.
And if you apply it within the USA, you need to pick one of MIT and Stanford and Carnegie Mellon, and burn the other two to the ground.
Of course, doing this will slow the development of AI. But that's a good thing, if UFAI is most likely and has zero utility.
In fact, if slowing development is good, probably the best thing of all is just to destroy civilization and stop development completely.
Do you agree with any of this? Is there a point where you think it goes too far? If so, say where it goes too far and explain why.
I see two main flaws in the reasoning.
ADDED: A number of the comments so far imply that the first AI built will necessarily FOOM immediately. FOOM is an appealing argument. I've argued in favor of it myself. But it is not a theorem. I don't care who you are; you do not know enough about AI and its future development to bet the future of the universe on your intuition that non-FOOMing AI is impossible. You may even think FOOM is the default case; that does not make it the only case to consider. In this case, even a 1% chance of a non-foom AI, multiplied by astronomical differences in utility, could justify terrible present disutility.