Their belief system, for those that don't just believe it for religious reasons, is that the earth cannot be a sphere because they cannot see the curvature. They also seem to believe that they are the first ever people on the planet to wonder about the stars and the universe and to ask questions like, "How do you know there is curvature if you can't see it?" and they conclude that there is no science that answers their questions and that, since they have not found any evidence of a round earth (because they haven't looked for it) and it SEEMS flat, therefore it is. 

Then they adopt all of the crazy arguments to support this fantasy, including that Antartica is not a continent, per se, but a 60,000 mile ice rim around the circumference of the earth that you cannot go to (despite the fact that you can just book a cruise there) and that is guarded by 10's of thousands of UN ships to prevent people from going there and finding out the truth that the earth is flat. 

They also believe that the earth is covered in a dome that cannot be breached, and hence no one has or can go to space, that everything NASA does is completely faked, and that even satellites either do not exist or are just circling the earth with a hot air balloon attached to them.  They believe that GPS is ground-based, and that satellite dishes are pointed in the air as part of a worldwide conspiracy to make us believe that satellites, space,  and a round earth exist, but that these  dishes are really just receiving ground based information. 

The level of ad-hoc arguments and claims of conspiracy go on and on, to the point that the conspiracy has to be on such a massive scale that the leaders of every country are involved, that every image of the earth, every  satellite that is visible with a telescope, every manufacturer of satellites, and even shipping companies and airlines are in on the conspiracy to hide the true nature of the earth from us. 

And surprisingly, this is gaining serious traction! People are eating this stuff up. 

What do they say when you show them their facts are wrong? They ignore them, call you a brainwashed NASA lover, or change the subject to say that you can't show them proof that the earth is a spinning ball flying through space and, so you are a brainwashed fool. 

When you try to show them proof that the earth is a spinning ball flying through space,  they just say that all scientists are freemasons or Jesuits or something like that,  who work for the government and are contracted to create science to fool everyone into hiding the true nature of the earth. 

So they deny any and every bit of science you can provide, and only will accept evidence that they can 'see with their own eyes' (Zetecisism), which is one of the reasons I did this particular piece. However, when you give them experiments they can do themselves, like this one, or perhaps going on a cruise to Antarctica, or even just watching the sun on the spring equinox to see where it sets and try to reconcile that on a flat earth map, they just laugh and call you brainwashed and tell you to prove we are on a spinning ball.. of course, without using any science, or even using observations like I've done here. 

It's really an incredible cult that they can believe this nonsense.