Am I just prejudiced again a flat earth?
First, sometimes when I object to Flat Earth arguments, some people claim that I’m just expressing my fixed prejudices and indoctrinated beliefs.
As it happens, I had a science teacher in school who put all sorts of arguments against a spherical Earth to us repeatedly and at great length. He got us arguing in our own time and racking our brains for arguments on both sides. It really made us think, and I took those ideas quite seriously.
So far from being indoctrinated, I was led to think for myself. That's in the spirit of science “take nobody’s word for it” (Nullius in verba) as is written over the door of the oldest existing science organisation in the world, the Royal Society of London. “Check for yourself, experiment, reason, calculate”. That is science.
My father was a navigator in RAF Lancaster bombers in the 1940s, He was responsible for guiding the aircraft accurately round Europe and later around Africa. If the scientific understanding of the shape of there earth was false, he and the other six crew members with him would have been hopelessly lost, they would all have died and I wouldn’t be here now.
I’ve talked to people who have flown very high and seen the curvature of the Earth with their own eyes. Other people posting here have seen it for themselves. No indoctrination, no third hand arguments. Perhaps, as conspiracy theorist might claim, they were all lying?
But you don't have to take anyone’s word for it - test it for yourself. Wherever possible, I’ve suggested ways that you can go out and test the question for yourself, with simple instruments ; a long stick, a protractor and a ticket to travel between two points about 200 miles apart, or a pair of binoculars.
No indoctrination, no blindly believing authorities – see for yourself!
The Earth does curve, demonstrably and clearly! Test it out, people. Nullius in verba.