Please start with Part 1, below.
Now that I've made my own default views somewhat clear, I can talk about what radical honesty is, and the implications. Ed's words to me were that he defines the central imperative of radical honesty as, "Be as open as humanly possible, and then minimize harm." (That's a loose paraphrase, not a direct quote. Feel free to correct me in the comments, Ed.)
I would break it down into two imperatives: never lie, and always share relevant information. To me, it's akin to a monastic discipline like abstinence or silence. I had a lover with whom I practiced radical honesty, a long time ago, and it was a real challenge, and led to a lot of insights, but it was very difficult and made our relationship pretty dramatic at times. I think it's a good thing to try at least once, assuming you have a partner willing to try it with you.
There are two related things that I'm really enjoying about Ed, and one is directly this matter of honesty. Sometimes he says exactly the wrong thing, and other times he says something so great you can't believe you're hearing it; you believe him in the latter cases because of the former. And because he (compulsively? by choice?) brings up problems almost immediately (which I know partly from tracking his relationship with Mel on their blogs, and hearing about it from him), you really can know that "no news is good news" - it's really not likely that he's saving up things to gripe about later. And if you ask him a question, you'll get a (sometimes painfully) true answer. All of this has a way of being comforting even while it is challenging.
I'm experiencing this as a relief from Mosch's more strategic approach to honesty, but, as I have told both of them, I could just as easily experience Mosch's tact and care as a relief from Ed's bluntness.
I know from the past that I am capable of radical honesty when I choose, so I am trying this with Ed as well. I had an opportunity recently to reassure him in a way that was so cost-free and so ultimately meaningless, and yet so potentially painful to withhold, that only an idiot or a total jackass would have withheld it, and yet I did so because answering the question that way was not quite truthful. And when I told him later that I would have answered differently for anyone else, he thanked me sincerely for the honesty. The guy knows what he wants, and so far he can take it as well as dish it out.
His wanting it doesn't make it the best strategy for me. Probably my best strategy given his preferences would be to do enough to give the appearance of radical honesty, while still being strategic the rest of the time. But I am willing to risk harm to my interests - and to his - in order to actually give him what he wants in this way.
Or at least to try.