The famous skeptic and illusionist, James Randi, once said: "I have absolutely no belief in an afterlife...I am a realist." On the other end of things, there are those who quote the old saying by Stuart Chase: "For those who believe, no proof is necessary. For those who don't believe, no proof is possible." I'm not sure of the exact context of Chase's quotation, but I have seen it used by religious folk as a defense of faith. Used in that context, I think both Chase's quotation and Randi's are equally foolish.
I have addressed the idea of fence-sitting before. There is an extreme anger toward those who wait to declare an opinion until they had thoroughly reasoned it through. While eternal fence-sitting is non-productive, the view from the fence is the best one to serve as a prelude to the drawing of a conclusion.
The assumption that the unexplainable is untrue is not realism; it's stupidity. As I have said before, there are a lot of things in quantum physics that can't be explained, yet they are. Granted, I don't believe people sit on clouds and play the harp in heaven, but for one to write off a belief in the afterlife while living in a world full of scientists who believe in the probability of alternate universes just strikes me as asinine.
The transcendentalists believed that intuition was the path to truth -- that it overcame the limitations of the senses. They did not believe that reason through observation was useless, but that it can only take us so far. Intuition was the way to the deepest of truths. Intuition does for the understanding of the natural world what poetry does for the understanding of the human condition: It does not tell us how the joints of existence are connected, but gives us an emotional understanding of its life-force.
The world should not be an either-or place. James Randi has done some great work, but it's as foolish to say that being a realist precludes the idea of an afterlife (of any kind) as it is to say that heaven is a big cartoon full of people lying around on cumulus chaise-lounges.