Well, the negative-time solution can be eliminated by using math too - "the theory" was never the equation with two roots - it was the process you used to get the right answer. What I want to know is, can you grok a case where the actual correct theory isn't physically intuitive, but is correct?
http://www.scottaaronson.com/blog/?p=1103
Eliezer's gung-ho attitude about the realism of the Many Worlds Interpretation always rubbed me the wrong way, especially in the podcast between both him and Scott (around 8:43 in http://bloggingheads.tv/videos/2220). I've seen a similar sentiment expressed before about the MWI sequences. And I say that still believing it to be the most seemingly correct of the available interpretations.
I feel Scott's post does an excellent job grounding it as a possibly correct, and in-principle falsifiable interpretation.