As you might have guessed, I'm someone that likes to keep an open mind, irrespective of how outlandish a particular theory or thesis might initially appear.
And as you probably already know, the flat earth theory has gained incredible traction in recent years. Yes, this sounds absolutely batsh-t crazy when people first come across it, but I'll tell you what -- some of the serious proponents of flat earth raise some good questions to think about.
That said, one common theme that comes up in the flat earth community is gravity -- they don't believe it exists. Instead, many suggest that buoyancy, not gravity, is at work on our planet.
Here's the thing -- gravity is most definitely REAL!
I think some folks in the flat earth community get hung up on the term "theory," as in, gravity is "just" a theory.
But just like "work" means something different in the real world as opposed to the principles of physics, theory gets misused by those who may not have a proper understanding of scientific terms.
In short, theory is just underneath "law" in terms of absolute, scientific validity.
Theory is NOT a hypothesis -- anybody can come up with a hypothesis. But hypotheses that have been tested, retested, and retested again begin to meet the criteria for theory.
In other words, (genuine) theories are repeatable.
Now go test gravity!
You don't have to be extreme...please DO NOT jump off a tall building to "prove" gravity. You already know what will happen!
Just do this -- take a tennis ball, and take a bowling ball, and drop them from the same height at the same time. You'll notice that both balls hit the floor at the same time (roughly speaking, of course -- you need computers/robots to do this experiment precisely).
Now, you'll notice a couple of things. First, the bowling ball impacts the floor with far greater force than the tennis ball. So, the resultant force is very much different. Second, you'll obviously note that the bowling ball is much heavier than the tennis ball. So its weight, or more precisely, its mass, is different.
The only thing that remained constant is acceleration! In other words, gravity.
Concluding Thoughts
I absolutely encourage open-minded thinking and the search for truth, no matter how insane it may seem.
That said, if flat earth theory is to gain wider credibility, it has to undergo the same rigorous tests and examinations that other theories have experienced (or should experience).