Hello,
(Warning: I did not come to the final point with this post, and I need a break for now, but it is far enough to start some discussion. most of this first post is an explanation of what this topic is about and how I would like to have the format of discussion. If you don't want to think hard, this topic is not for you.)
with this topic I want to outline a very clear reasoning, which will, either proof, or at least give a very strong indication that the earth must be spherical (i.e. close to sphere-shaped, not a perfect sphere, as noone would try to reason, but to be precise).
To clarify, with reasoning I mean using nothing but logic / simple math and easily doable experiments that anyone can do with very small effort preferably in their room without buying any tools. Maybe simple things like a stopwatch, a meter scale, a weight scale, some arbitrary small objects, a glass, some water, ... will be required.
To get more specific, this topic is about gravity, or whatever a gravity-doesnt-exist believer wants to call the "circumstance" that makes things go "towards the floor". As, at least as far as I know, everyone knows that flat earth cannot work without gravity (which however, will be another thing to discuss, if we ever get to conclude that gravity works as science says in this topic..)
This topic requires being very precise with every argument.
Don't waste time and/or spam by citing sources (a time waste, since they are always cherry-picked) or invoking "common sense".
Why no common sense? Because clearly "common sense" of either flat-earthers, or globe-earthers is fundamentally wrong, so no use refering to it.
Also, please don't mention a million points at once, this will just blow up the thread if we want to be precise.
A good state of mind before posting might be, think of the one you are trying to explain something to, as not a human, but a machine, which can't do anything if you don't explain every little detail step by step. If we manage to do that, anyone smarter than a machine (which hopefully is everyone) should be able to follow.
Not relevant disclaimer on why I'm doing this topic
If you haven't figured it out by the above, I'm a physicist (hence, recognize the earth is pretty spherical). However, with the format of this topic as I outlined above, this should have no impact on anything we discuss. If it does, then we're not being precise enough. Anyway, being a scientist, I find it highly disturbing how silly believes can get and flat-earth has to be one of the top-runners. I don't particularly care if anyone believes in flat earth or not. But I do care when people are stubbornly convinced by nonsense, it is the worst thing you can possibly do. It only leads to misery and disaster, if you pick the wrong thing to be convinced by (luckily, flat-earth is harmless in that regard).
Anyway, that's my reason for this topic. No more details, as it's a completely different topic.
If something is too hard to experimentally verify, discard it's discussion. One can always say "but go check it yourself", but let's be honest for the sake of forum-discussion, noone ever does if it's not super-simple to do so (hence the format of the topic). Not because of spite, but because people have limited time and resources which can make it simply impossible (that's why science exists to do the job..).
Note I said experimentally, if something is just logically too hard to follow, it should not be discarded (that's the reason discussions like this never go anywhere..), and kept on the discussion table indefinitely. In this regard, I am very stubborn, I might or might not ignore any other arguments if there's even one that's not understood.
Also please recognize we are humans and make mistakes, don't be a child and make accusations for mistakes, while not even trying to understand the arguments, or corrections, if mistakes have been made. If you don't want to think hard and understand, then this thread is not for you, you can leave now.
Finally, on the actual topic.
I'll try to list elementary points as clearly as possible.
1.
As I understand, every flat-earther needs to do away with gravity,
as gravity is what makes sufficiently huge amounts of "stuff" attract and deform each other into spherical shapes. This point should be the last-dicussed one and the end-goal, as it is hard or even impossible to do with pure reasoning. So I would not discuss it right away, but please mention if you are flat-earther and do recognize gravity as a true thing, and how that works.
2.
I think we can agree that stuff tends to move "towards the floor",
so let's call this phenomenon "fallforce" (if you say there is no force.. forgive my naming creativity, just use it as a name to refer to whatever you believe). I.e. for me the fallforce would be gravity. For flat-earthers, I guess it would be buoyancy. (Physic note: yes, actual gravity as in GR is not a force, but Newton gravity is precise enough to conclude a globe earth, and not unreasonable to verify with very limited tools)
I underlined the arguments for discussion, the rest of the text is only to give an explanation. Like I said, I would prefer to leave 1. for now, and just stick to 2.
For now I can see two discussions 'branches' that could come up:
Branch 1:
Give a detailed explanation of how the fallforce works. Specifically, why is down.. "down", as in towards the floor, however you define floor if not by saying "where stuff moves towards". I have never seen flat-earther even try to explain this. And sadly, I have never seen debate mention this point.
Branch 2:
You don't have an explanation for your version of the "fallforce". That's o.k.. It will get more complicated as I will have to give a full outline first on how 1. leads to 2. and leads to spherical earth. Then you just have to find 1 flaw with it.
I'd like to keep both branches separate for discussion, if anyone even belongs to branch 2, I don't know. However I already spend hours writing this now, so I'll get back to it later, feel free to take branch 1 for now. Be reminded to please use clear step-by-step logic or maths to assist your reasoning (if you don't think maths works.. uh.... we can discuss why, but it's going to be hard to discuss anything)
I want to not forget this thread, but I also just did this on impulse, so I can't guarantee I'll actually keep posting.. if not, maybe at least this first post will incite some others to discuss in this format. Or it could be too much text wall and noone wants to bother.. but hey at least I tried.