Every Universe exists depending on the Knowledge that reflects it and not in its absence.
It is absolutely true that our ancestors saw this universe before and after we were born and this is why we think that the Universe exists irrespective of our existence.
It is an illusion as big as the Illusion of our Life with our entire universe, because our ancestors too saw the world through these senses that we have too, they were human being too, a part of the human race. For the members of a tribe, for instance, their Universe expands up to the borders on their Knowledge of this world. If these borders are very small, the world will be very small and the other way around. Our Universe will look completely different to an animal, even if we think it sees the same images we do. It is true that we are aware, in the Illusion of our Life that the animal sees the same images, but he will interpret them differently, depending on his level of competence, which will entail a different image of the Universe. The same happens with human beings, who think based on a Logical Coefficient 2 and cannot conceive a world where the beings think and see an universe based on Logical Coefficient superior to the one of the man. That world and the universe that will include it will be completely different to the one that reflects and includes our world.
Then the meaning of the man's existence in this world which is for us vanity of the vanities, for a different thinking belonging to a different Logical Coefficient, can be something different.