Georgina,
You seem to be denying that science can even exist because you seem to think that people are full of illusion and delusion about the world.
As I said, it is a wonder that any animal or person could survive for even a day, if the world were as full of illusion and delusion as you seem to think it is.
In fact, it is only on the high-level details, of human analysis of the world, that people disagree.
All (except, seemingly, you) agree on the fundamentals, i.e. that the sky is blue, and the grass is green, and they can all agree when a tiger is chasing them. But people might disagree on the high-level details of human analysis of the world, i.e. what political party to vote for; or what is the best physics’ theory of the world.