Specifically with regard to the apparent persistent disagreement between you and Robin, none of those things explain it. You guys could just take turns doing nothing but calling out your estimates on the issue in question (for example, the probability of a hard takeoff AI this century), and you should reach agreement within a few rounds. The actual reasoning behind your opinions has no bearing whatsoever on your ability to reach agreement (or more precisely, on your inability to maintain disagreement).
Now, this is assuming that you both are honest and rational, and view each other that way. Exposing your reasoning may give one or the other of you grounds to question these attributes, and that may explain a persistent disagreement.
It is also useful to discuss your reasoning, if case your goal is not to simply reach agreement, but to get the right answer. It is possible that this is the real explanation behind your apparent disagreement. You might be able to reach agreement relatively quickly by fiat, but one or both of you would still be left puzzled about how things could be so different from what your seemingly very valid reasoning led you to expect. You would still want to hash over the issues and talk things out.
Robin earlier posted, "since this topic is important, my focus here is on gaining a better understanding of it". I read this as suggesting that his goal is not merely to resolve the disagreement, and perhaps not to particularly pursue the disagreement aspects at all. He also pointed out, "you do not know that I have not changed my opinion since learning of Eliezer's opinion, and I do not assume that he has not changed his opinion." This is consistent with the possibility that there is no disagreement at all, and that Robin and possibly Eliezer have changed their views enough that they substantially agree.
Robin has also argued that there is no reason for agreement to limit vigorous dissension and debate about competing views. In effect, people would act as devil's advocates, advancing ideas and positions that they thought were probably wrong, but which still deserved a hearing. It's possible that he has come to share Eliezer's position yet continues to challenge it along the lines proposed in that posting.
One thing that bothers me, as an observer who is more interested in the nature of disagreement than the future course of humanity and its descendants, is that Robin and Eliezer have not taken more opportunity to clarify these matters and to lay out the time course of their disagreement more clearly. It would help too for them to periodically estimate how likely they think the other is to be behaving as a rational, honest, "Bayesian wannabe". As two of the most notable wannabe's around, both very familiar with the disagreement theorems, both highly intelligent and rational, this is a terrible missed opportunity. I understand that Robin's goal may be as stated, to air the issues, but I don't see why they can't simultaneously serve the community by shedding light on the nature of this disagreement.
It happens every now and then that someone encounters some of my transhumanist-side beliefs—as opposed to my ideas having to do with human rationality—strange, exotic-sounding ideas like superintelligence and Friendly AI. And the one rejects them.
If the one is called upon to explain the rejection, not uncommonly the one says, “Why should I believe anything Yudkowsky says? He doesn’t have a PhD!”
And occasionally someone else, hearing, says, “Oh, you should get a PhD, so that people will listen to you.” Or this advice may even be offered by the same one who expressed disbelief, saying, “Come back when you have a PhD.”
Now, there are good and bad reasons to get a PhD. This is one of the bad ones.
There are many reasons why someone might actually have an initial adverse reaction to transhumanist theses. Most are matters of pattern recognition, rather than verbal thought: the thesis calls to mind an associated category like “strange weird idea” or “science fiction” or “end-of-the-world cult” or “overenthusiastic youth.”1 Immediately, at the speed of perception, the idea is rejected.
If someone afterward says, “Why not?” this launches a search for justification, but the search won’t necessarily hit on the true reason. By “‘true reason,” I don’t mean the best reason that could be offered. Rather, I mean whichever causes were decisive as a matter of historical fact, at the very first moment the rejection occurred.
Instead, the search for justification hits on the justifying-sounding fact, “This speaker does not have a PhD.” But I also don’t have a PhD when I talk about human rationality, so why is the same objection not raised there?
More to the point, if I had a PhD, people would not treat this as a decisive factor indicating that they ought to believe everything I say. Rather, the same initial rejection would occur, for the same reasons; and the search for justification, afterward, would terminate at a different stopping point.
They would say, “Why should I believe you? You’re just some guy with a PhD! There are lots of those. Come back when you’re well-known in your field and tenured at a major university.”
But do people actually believe arbitrary professors at Harvard who say weird things? Of course not.
If you’re saying things that sound wrong to a novice, as opposed to just rattling off magical-sounding technobabble about leptical quark braids in N + 2 dimensions; and if the hearer is a stranger, unfamiliar with you personally and unfamiliar with the subject matter of your field; then I suspect that the point at which the average person will actually start to grant credence overriding their initial impression, purely because of academic credentials, is somewhere around the Nobel Laureate level. If that. Roughly, you need whatever level of academic credential qualifies as “beyond the mundane.”
This is more or less what happened to Eric Drexler, as far as I can tell. He presented his vision of nanotechnology, and people said, “Where are the technical details?” or “Come back when you have a PhD!” And Eric Drexler spent six years writing up technical details and got his PhD under Marvin Minsky for doing it. And Nanosystems is a great book. But did the same people who said, “Come back when you have a PhD,” actually change their minds at all about molecular nanotechnology? Not so far as I ever heard.
This might be an important thing for young businesses and new-minted consultants to keep in mind—that what your failed prospects tell you is the reason for rejection may not make the real difference; and you should ponder that carefully before spending huge efforts. If the venture capitalist says, “If only your sales were growing a little faster!” or if the potential customer says, “It seems good, but you don’t have feature X,” that may not be the true rejection. Fixing it may, or may not, change anything.
And it would also be something to keep in mind during disagreements. Robin Hanson and I share a belief that two rationalists should not agree to disagree: they should not have common knowledge of epistemic disagreement unless something is very wrong.2
I suspect that, in general, if two rationalists set out to resolve a disagreement that persisted past the first exchange, they should expect to find that the true sources of the disagreement are either hard to communicate, or hard to expose. E.g.:
If the matter were one in which all the true rejections could be easily laid on the table, the disagreement would probably be so straightforward to resolve that it would never have lasted past the first meeting.
“Is this my true rejection?” is something that both disagreers should surely be asking themselves, to make things easier on the other person. However, attempts to directly, publicly psychoanalyze the other may cause the conversation to degenerate very fast, from what I’ve seen.
Still—“Is that your true rejection?” should be fair game for Disagreers to humbly ask, if there’s any productive way to pursue that sub-issue. Maybe the rule could be that you can openly ask, “Is that simple straightforward-sounding reason your true rejection, or does it come from intuition-X or professional-zeitgeist-Y ?” While the more embarrassing possibilities lower on the table are left to the Other’s conscience, as their own responsibility to handle.
1See “Science as Attire” in Map and Territory.
2See Hal Finney, “Agreeing to Agree,” Overcoming Bias (blog), 2006, http://www.overcomingbias.com/2006/12/agreeing_to_agr.html.