We first understand that the Earth is flat based upon our perceptions. The same reason we know that a stop sign is red and that cartoons are magic pictures that move.
For the round-Earth lie to succeed, pilots, NASA and birds would all have to be in on the conspiracy. Pilots and astronauts are bribed with that sweet sweet round-earth lobbyist money. Birds can be bribed with sunflower seeds.
If the Earth isn’t flat, then Terry Pratchett is a liar. Are you calling Terry Pratchett a liar?
There isn’t a Round Earth Society.
For the Round-Earth Theory to work, there would have to exist some kind of exotic force… call it “gravity”; and, that’s just nuts.
Because the flat Earth is only forty miles thick, no one has managed to get to the other side (where the My Little Ponies live). It’s nearly impossible to get through because the bottom layer is a space-age polymer plastic developed by NASA when astronauts didn’t land on the moon.
If the Earth weren’t flat, we’d be in a heliocentric arrangement and the Earth would be like all the other planets… no better than Mercury… Can you believe it? Mercury!
If the Earth isn’t flat, why are things always falling off of the face of the Earth… like Peaches and Herb, Al Gore and that girl from The Wonder Years…
The Flat-Earth model offers simple, easy-to-understand answers to questions like, “How can I reject science and logic entirely and still feel smug about it?”