I've read a fair amount on Less Wrong and can't recall much said about the plausibility of some sort of afterlife. What do you guys think about it? Is there some sort of consensus?

Here's my take:

• Rationality is all about using the past to make predictions about the future.
• "What happens to our consciousness when we die?" (may not be worded precisely, but hopefully you know what I mean).
• We have some data on what preconditions seem to produce consciousness (ie. neuronal firing). However, this is just data on the preconditions that seem to produce consciousness that can/do communicate/demonstrate its consciousness to us.
• Can we say that a different set of preconditions doesn't produce consciousness? I personally don't see reason to believe this. I see 3 possibilities that we don't have reason to reject, because we have no data on them. I'm still confused and not too confident in this belief though.
• Possibility 1) Maybe the 'other' conscious beings don't want to communicate their consciousness to us.
• Possibility 2) Maybe the 'other' conscious beings can't communicate their consciousness to us ever.
• Possibility 3) Maybe the 'other' conscious beings can't communicate their consciousness to us given our level of technology.
• And finally, since we have no data, what can we say about the likelihood of our consciousness returning/remaining after we die? I would say the chances are 50/50. For something you have no data on, any outcome is equally likely (This feels like something that must have been talked about before. So side-question: is this logic sound?).

Edit: People in the comments have just taken it as a given that consciousness resides solely in the brain without explaining why they think this. My point in this post is that I don't see why we have reason to reject the 3 possibilities above. If you reject the idea that consciousness could reside outside of the brain, please explain why.