When he was paraphrasing the reasons:
Human value is fragile as well as complex, so if you create an AGI with a roughly-human-like value system, then this may not be good enough, and it is likely to rapidly diverge into something with little or no respect for human values
... that doesn't seem quite right. The main problem with values being fragile isn't that a "roughly-human-like value system" might diverge rapidly; it's that properly implementing a "roughly-human-like value system" is actually quite hard and most AGI programmer seem to underestimate it's complexity, and go for "hacky" solutions, which I find somewhat scary.
Ben seems aware of this, and later goes on to say:
This is related to the point Eliezer Yudkowsky makes that "value is complex" -- actually, human value is not only complex, it's nebulous and fuzzy and ever-shifting, and humans largely grok it by implicit procedural, empathic and episodic knowledge rather than explicit declarative or linguistic knowledge.
... which seems to be one of the reasons to pay extra attention to it (and this also seems to be a reason given by Eliezer, whereas Ben almost presents it as a counterpoint to Eliezer).
Human evaluation of human values under specific instances is everything that Ben says it is (complex, nebulous, fuzzy, ever-shifting, and grokked by implicit rather than explicit knowledge).
On the other-hand, evaluation of a points in the Mandelbroit set by a deterministically moving entity that is susceptible to color-illusions is even more complex, nebulous, fuzzy, and ever-shifting to the extent that it probably can't be grokked at all. Yet, it is generated from two very simple formulae (the second being the deterministic movement of the entity).
Elieze...
[...] SIAI's Scary Idea goes way beyond the mere statement that there are risks as well as benefits associated with advanced AGI, and that AGI is a potential existential risk.
[...] Although an intense interest in rationalism is one of the hallmarks of the SIAI community, still I have not yet seen a clear logical argument for the Scary Idea laid out anywhere. (If I'm wrong, please send me the link, and I'll revise this post accordingly. Be aware that I've already at least skimmed everything Eliezer Yudkowsky has written on related topics.)
So if one wants a clear argument for the Scary Idea, one basically has to construct it oneself.
[...] If you put the above points all together, you come up with a heuristic argument for the Scary Idea. Roughly, the argument goes something like: If someone builds an advanced AGI without a provably Friendly architecture, probably it will have a hard takeoff, and then probably this will lead to a superhuman AGI system with an architecture drawn from the vast majority of mind-architectures that are not sufficiently harmonious with the complex, fragile human value system to make humans happy and keep humans around.
The line of argument makes sense, if you accept the premises.
But, I don't.
Ben Goertzel: The Singularity Institute's Scary Idea (and Why I Don't Buy It), October 29 2010. Thanks to XiXiDu for the pointer.