The problem with existence is how something can exist if we cannot interact with it. Then we can think and rethink things like the metaverse. Is our universe one of the many or unique things in the universe? This is one of the most interesting philosophical questions. When we think about the history of science, there is quite a short time, when humans thought that the Earth was the center of the universe. And until the 1980s we thought that our solar system was unique in the universe. There were rumors about things like extrasolar planetary systems. But then in one day, researchers found the first exoplanets. Researchers found the first exoplanets near Proxima Centauri in 2016. Our knowledge about the universe expands. And today we know that our galaxy cluster is one of many galaxy clusters that are part of galaxy superclusters. So why the universe cannot be one of many universes? This is one of the most interesting things in history. Somebody says: that serious scient...