Why doesn't a single power rule the world today?
[I'm taking advantage of the new "LW posts as blog posts" format to post something I'm pretty unsure about. I'm working from my memories of the blog posts, and from a discussion I had with Robin Hanson and Katja Grace in late 2012. Please let me know if any of this is inaccurate!]
One of the key differences of opinion in the Hanson-Yudkowsky AI-Foom Debate is about the idea of a "decisive advantage". If I'm not misrepresenting the parties horribly, the idea is that some point in a world with AGI, some AGI-enabled party uses their greater intelligence to increase their general power: money, resources, control over others, intelligence and suchlike. That greater power increases their ability to gain power, resulting in a snowball effect that ends with some party having control over the outcomes for all of Earth-originating life.
Robin asks the very reasonable question: if that's how things work, why hasn't it already happened? What stops the largest business using its decisive power over smaller ones to defeat and absorb them, growing ever larger and more powerful until all other businesses fall to its power? Why do we have multiple nations today, when this model would seem to predict that a single state should ultimately conquer and rule all? I don't remember Robin proposing an answer of his own: a mechanism or theoretical model that would lead us to expect multiple powers. But it seems like a good question, and it's bugged me ever since.
I think I'd need to be much more of a student of history than I am to have any confidence in an answer, so let me share some wild speculation that might at least start discussion:
Regulation: Such growth isn't an option for legal businesses at all, because states exist. So powerful a business would challenge the power of the state, and the state is in a position to disallow that. The explicit purpose of monopoly legislation is to stop a business which has become very powerful in one area from leveraging that to become powerful elsewhere.
Principal-agent problems: it sure would be easier to keep an empire together if you could reliably appoint generals and rulers who always did what you told them to. Especially if the round-trip time for getting them a message is on the order of weeks, and you have to entrust them with the discretion to wield tremendous power in the mean time.
Moral norms: Nuclear weapons gave the USA a decisive advantage at the end of WWII. If the USA had been entirely ruthless and bent on power at any cost, it would immediately have used that advantage to cripple all rivals for world superpower and declared its rulership of the world.
I don't expect any of these factors to limit the growth of an AGI. Is there some more general limit to power begetting power that would also affect AGI?