I found the debate almost unwatchable. There's no discussion, there's just a couple of good bits where Carroll talks sense. I don't imagine many LessWrongers will enjoy it.
The other group were non-reductionists. If non-reductionism is true, and souls really do exist, that would alter our fundamental understanding of physics - that the basic building blocks of the universe include souls, that they can transfer energy and information etc.
One of the things that irritated me was the lack of discussion however. They didn't really get to attack each other's arguments much.
Well, not quite, but close. The debate starts 1 hour after this post is up. From Sean's blog post:
Is There Life After Death? A Debate
No, there’s not. In order to believe otherwise, you would have to be willing to radically alter our fundamental understanding of physics on the basis of almost no evidence. Which I’m not willing to do. But others feel differently! So we’re going to have a debate about it tonight — to be live-streamed.
Note that Sean did extremely well against W.L. Craig (LW discussion), so this should be interesting. His co-debater Steven Novella runs The Skeptics' Guide to the Universe podcast, well worth listening to.