RadioLab did an episode on this topic “Decoding the Void” in 2014 ( https://www.radiolab.org/episodes/anesthesia ) that, for me, pretty much deconstructed the whole idea of an afterlife in 20 minutes. What happens when we die? People commonly think of this as some kind of unknowable mystery. But people lose consciousness all the time and aren't entering the spirit world when they do so. If you’ve ever awoken from gen…
While the rational side of me thinks that death is probably oblivion, I just don't want to admit it. After a friend of mine passed away, I did a lot of soul searching and basically came to the conclusion that there's nothing after death. It was mentally destructive for me and sent me into a bout of depression. I'd hate to think that we're going through all this just to have your entire life multiplied by 0 at the end…
The not-knowing factor (of what happens in your life) is what drives most people to live, so why wouldn't give one a positive drive to actually live life and find out the same thing about death. You just don't skip high school to find out things what life in 40s will be like. :)
Edit: I hope I did't invoke illusion of being religious in any way. It's a purely philosophical way of questioning something you cannot possibly know.
Edit2: Also, other repliers (that obviously read more books than me) explain some really great theories