How did we learn the meaning of "forever"? How did we begin to imagine it, when it has no concrete example in reality? In all our experience with the natural world, and the universe, we've seen, over and over, that everything is transient, and temporary. Everything and everybody dies.
Of course, life begins again, and time moves on. But there is nothing that guarantees this cycle will go on forever. And still, we can imagine it. In fact, we've thought and written about it for as long as collective human history can remember.
How are we able to have an idea of the infinite -- of forever -- when we have no experience of it? What other species on earth has the same ability?