That’s a really difficult question becuse practically it is very hard to know. Some religions teach people to believe very strongly in life after death and that you can be reincarnated or your spirit or your soul will live on once you have died. But not everyone belives this.
Personally I’m not sure what I think about it because as a scientist I like to try to prove or disprove things and then decide what I think; but that’s quite hard to do in this case. I think that many people find comfort in believing in life after death and that itself is a good thing.
As Amy points out, this can never actually be proven or dis-proven. As such, it really is a matter of opinion and belief rather than fact.
Personally, I take a default position of not believing in something until I am presented with evidence to suggest that it is more likely that it does exist than it does not exist. This is sometimes referred to as ‘the burden of proof’. If the claim is that something exists, it is up to person claiming that it does exist to supply evidence (they have the burden). It is not up to someone who does not believe it exists to prove that it does not.
I would like to add though, that this is purely my opinion and someone else may well have a completely different philosophy.