Vanishing into oblivion is too vague away to say it. Saying our souls leave us, go to pergatory, then heaven is too complex. Personally, I believe that we live on. But not as a thinking being. We live on through those we've influenced. The memories we leave. The differences we make. Example being if Adolf Hitler were not born 96% (totally random estimate) would not be here. Why? because millions of people would still be alive and likely have influenced things in a way your parents may not have married or met. Why? because the average human effects 10 000 people (some more, some less, this is a true fact). well what's 10 000 times the total casualties of WWII ? A lot of people.