If animals and bugs just go to nothingness, why do humans think humans do anything else but go to nothingness?

If everything that's alive just dies and goes into nothingness, why do humans think they don't also just go to nothingness, since there is no proof otherwise. The only thing science has ever said to have existed is the Metaphysical world, but that's it. And the people who have seen it have always been bought back to life, so no one knows if they stay there anyway, it could just be because they weren't dead dead yet.