Have you ever been rock climbing? I assure you that the fact that you're safe, and even the fact that you know you're safe, does not shut off the (untrained) lizard brain, at least not the sort of lizard brain that's afraid of heights.
I haven't been rock climbing, but I can tell you that the main reason I'm scared of heights is because I get an urge to jump off, and I have to fight it back down again. If there's a full glass window or something between me and the drop, on the other hand, heights don't bother me at all.
ETA: There is now a third thread, so send new comments there.
Since the first thread has exceeded 500 comments, it seems time for a new one, with Eliezer's just-posted Chapter 33 & 34 to kick things off.
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