Flat Earth
Flat Earth is what happens when you combine at least 8 years of religious homeschool indoctrination along with daily doses of Prozac while also including blunt force trauma to the head. It takes a life deprived of experiencing the perspective of 100 ft elevation, deprived of being taught basic geometry, deprived of simple answers to simple questions in order to believe this bucket of lies brought about by scripture and people whom are dumber than a bag of hammers. Dumber than Congress. Dumber than G Man's shit. Even relying on framework as bankrupt as governmental epistemology would not justify one's belief in this concept. Should you encounter Mr. Turtle that hold the purported flat Earth on his shell, please tell him for us that.
The flat Earth is a crappy idea about the shape of the Earth, which can be easily disproved by simple observations that anyone make who has some spare time and a camera. Also, flat Earth has no cohesive or agreed-upon model, making it nearly impossible to test. This isn't helped by the fact that flat Earthers are the campions of post-hoc explanations, inventing new terms or assigning new meaning and properties to existing terms so that someones test or observation doesn't REALLY disprove a flat Earth (see Betty Van Velsen).
They also typically use certain buzz-words they don't understand to describe terms and effects they don't understand like: perspective, the atmosphere, refraction, lensing, gravity, and more.
Connections to other Forms of Pseudoscience
Acceptance of the flat Earth generally comes with Biblical literalism, geocentrism, young-Earth creationism, and an acceptance of many other conspiracy theories such as the faking of the moon landing and most massacres, 9/11, all of science in general, and even ancient aliens, often involving the illuminati, freemasons, zionists or a combination of them.
*(please expend upon)
Things that debunk the Flat Earth
The evidence against the flat earth is overwhelming. Here's a bunch of diagrams that prove the earth by definition MUST be a spheroid of some kind, and not a gigantic communion wafer: