Math was never designed to be applied to real-life situations. What is the point of linear approximation? What is the point of life? Nobody can come to a conclusion and thus prove that the Earth is flat. However, it all depends on what you believe in. Yes, the horizon is always eye-level, so yes, I believe the earth is flat. It doesn't matter in any other perspective, only my sole perspective is what counts for me. Ignorance is bliss and I can proud to be an American.