Intuitive Counter-Argument #1 If the earth is flat, then shouldn't the entire planet be lit at noon, when the sun is highest in the sky? If I place a lightbulb over a flat table, the whole table is lit - meaning that it should be daytime here in the US, as well as all over the world at the same time. EDIT: Also, let me add that this argument you've put forth, even if successful, would only go to show that the universe is not as big as we originally thought. It has nothing to say about the geometry of the earth. Let me also add that we live in a non-euclidean geometry reality. I want to hear your arguments against that fact.