As a Christian I was watching this discussion with interest and here are my thoughts.
You don't have to go to Detroit to know it smells but you do have to have some information about it. You have to be getting some information from someone who has actually been there otherwise how would you actually know? If you have no contact with anyone who's actually been to Detroit then how could you know? If House is so adamant that there is no afterlife then he can't get information from someone who's actually been there and so his reasoning is always going to be fallible.
However, Wilson's answer is equally infuriating because all he is promoting is a 'we can't know for sure' attitude. If that is the case then who gives a monkey's whether it's there or not? If we can't know. If we don't have enough information then it can't really impact our lives.
The Biblical answer to this question is that there is an after life and we can know about it because someone has been there and told us about it. That person is Jesus Christ. So I don't believe every nut job who says they saw lights etc. But I do believe that at a point in history God came to earth and told us, not that Detroit smells, but that the afterlife is real and that we need to get ready for it.