fivebells .:
What does it mean, for the universe to actually exist? What would it look like if it didn't actually exist?
If the universe didn't actually exist, nothing would be here. We wouldn't be able to have this conversation.
That doesn't stop people from thinking it doesn't exist, though. This is commonly shown when people say things like, all there is is experience, and I can't say whether there is any desk or chair really here because all I experience is the colors (which don't exist anyway as not all species see colors) and sense of touch (and hard/soft also doesn't exist really because not everything experiences touch like that), etc. So the universe is seen to be an illusory play in one's mind that has no existence outside of that. What happens after I die in that case? Experience must surely continue in some way or another. What's death if my experience doesn't depend on my body? Maybe I will go to heaven or hell or be reborn in another body. etc. Or at best I can say "I don't know" and put off the question till later.
But really, as the only reason I'm conscious is because of this body, it's easy to tell what happens when I die, namely: all experience will stop, for me, and the rest of the universe will continue just fine. I am indeed mortal.
EDIT to add: The only way you could think the universe doesn't exist is if there is some sort of feeling-being around, in whatever form. That's because the feeling-being itself is indeed illusory/delusory, and it projects these qualities onto everything it experiences, even the senses. So the senses have this illusory quality to them, as a feeling-being. The mistake is thinking that illusory quality of the senses pertains to the universe/to all of experience, instead of to the feeling-being that is filtering them. When there is no feeling-being, there is a direct experience of the universe, and thus no doubt at all that the universe does indeed actually and inherently exist.