There is no evidence that the world is flat, nor that it was intentionally designed to be difficult but not impossible to detect if flat.
Conspiracy theorist Mark Sargent has created a multi-part video series attempting to prove the discredited flat Earth theory. He separates his theories into “clues” which are supposed to prove that planet Earth is flat and that a secret group Sargent calls “the Authority” is keeping this from the public eye. His videos are widely shared on social media and he has been recognized as an important figure in the modern flat earth movement. In part four of his series, Sargent explores the proposition that our planet is run as a “near-perfect” flat plane covered by a large dome, which he likens to a stadium. His main argument is that this system was designed to make it difficult – but not impossible – for human beings to understand the real conditions of their reality. He suggests that, unlike a mouse in a glass enclosure, we don’t really feel trapped. Instead, he likens flat Earth to a vast nature preserve, where humans barely notice they’re in an enclosed environment. The animals, he argues, are often unaware that they are confined because the area of the nature reserve is large enough to meet their needs. Humans, however, are curious as a species and will inevitably come to see the supposed truth of flat Earth. He cites the films Dark City, The Truman Show and The Village as examples. Additionally, Sargent expresses the belief that the harsh conditions of sea travel, air travel, and the perils involved in accessing Antarctica are evidence of a flat Earth designed to contain us, and that “the Authority” introduced the globe model to obscure the truth.
The flat Earth theory has been debunked countless times. In this video, Sargent provides no evidence, concrete or otherwise, that the Earth is actually flat. Instead, it speculates on human and animal psychology from a theoretical perspective. All the phenomena he mentions about the different borders, such as the seas filled with salt water instead of fresh water or the cold temperature of the Antarctic which makes it difficult to cross, do not testify to a desire to keep people away and are explicable natural phenomena. The poles are cold due to their distance from the equator, which means they receive much less sunlight than other parts of the planet. They also reflect light from their glossy white surfaces. Coldness and remoteness are natural functions of geography, not evidence of a barrier designed to keep people from seeing the edge of a flat world. Ocean salinity is caused by rain dissolving rocks that transport salts and minerals to the oceans via rivers, as well as hydrothermal vents that expel minerals from the ocean floor. There is no evidence that this salinity was part of a design to make ocean passage difficult for humans who need drinking water.
There is no evidence that our world was designed as a nature reserve or that the world itself is flat. All scientific evidence indicates that the world is an oblate spheroid.