Imagine a hermit living in a steep valley. He, although could easily be She, has never left the valley, never received a formal education, and has never been told of the existence of anything beyond the valley. Ask this person to draw a map of the world ("world" not being synonymous with "earth" but rather the world of his experience.) This person will draw something that probably looks like a bowl. "I see with my eyes the ground sloping up all around me. Therefore, the world is shaped like this bowl I eat my breakfast from."
I see no difference between this extreme example and someone saying "The world looks flat to me, therefore the world IS flat." The following thread
https://www.theflatearthsociety.org/forum/index.php?topic=73039.0has been pretty much devoted to totallackey saying "I see a flat earth therefore the earth is flat," JackBlack says, "no it isn't," totallackey says "yes it is..." and so on. Much of the FE proponents use this observational evidence as proof of a flat earth. "The Bonneville Salt Flats sure look flat to me, so the earth is flat. It even says so in the name."
I will be quite honest: if my experience had been growing up in and never leaving Kansas, then I might easily come to the same conclusion. The world is flat because I can SEE no evidence to the contrary. Fortunately, we have the experiences of others to draw upon, we have math like trigonometry that demonstrate, based on sun angles and distances, that the world cannot possibly flat.
https://www.theflatearthsociety.org/forum/index.php?topic=73074.0I am intelligent enough to defer to their experience, which is wider than my own. And then I gain my own experiences, which corroborate everything I have been told growing up. I can clearly see the sun dip below the horizon of the ocean on a clear evening. I can clearly see how Polaris is below the horizon when I fly in the southern hemisphere. I can clearly see the round shape of the earth's shadow on the full moon during a lunar eclipse, something ordinary in a RE model and unexplainable in any FE model I have seen.
Now, as an airline pilot, my entire career and the safety of my passengers and aircraft are predicated upon navigation on a round earth. I have even seen irrefutable evidence with my own eyes: In the winter, we have a flight that departs Komatsu mere minutes after sunset. Komatsu is on the coast, so I can clearly see the sun dropping below the horizon. The low bushes in the far distance do not interfere with the horizon more than a few arc minutes. I line up on runway 24 (about 240 degrees magnetic heading) and depart in that same direction, towards Fukuoka. After takeoff, I clearly see the ocean horizon; there are no clouds and no fog. As I climb, I experience something unusual: the sun appears to rise again. Was this the sun reappearing from the distant fog? Could it be that it was above the horizon the whole time and merely obscured? I check the horizon level on my heads up display. Nope, the sun is still below the horizon. The earth has dipped; the edge where the ocean meets the sky is now also below the horizon, and no longer obscuring the sun. The earth continues to drop below me, revealing more and more sky that would otherwise have been obscured by a flat earth. This continues for a good fifteen minutes until I reach cruise altitude at 33,000 ft. Then, even though I am chasing the sun at 550 mph, it slowly - more slowly than were I stationary - sinks again behind the earth. All of this is happening well below the horizon according to my heads up display. It's a "double sunset" and is quite common if you are in the right place at the right time.
So I can now state unequivocally, using exactly the same logic as totallackey: "I have seen with my own eyes that the earth is round. Therefore IT IS ROUND." That doesn't make it so. But I have mountains of evidence to back me up.