I believe he could do much more than censoring certain ideas, namely show that they are bogus.
I'm not a big fan of Eliezer, but that complaint strikes me as completely unfair. There is far less censorship here than at a typical moderated blog. And EY does expend some effort showing that various ideas are bogus.
I'm not an insider, or even old-timer, but I have reason to believe that the one single forbidden subject here is censored not because it is believed to be valid or bogus, nor because it casts a bad light on EY and SIAI, but rather because discussing it does no good and may do some harm - something a bit like a ban on certain kinds of racist offensive speech, but different.
And in any case, the "forbidden idea" can always be discussed elsewhere, assuming you can even find anyone that can become interested in the idea elsewhere. The reach of EY's "censorship" is very limited.
[...] 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.