From some videos I've watched, looks like FE believe eclipses are caused by a black sun...

That's one theory ... rooted in the beliefs of various early civilizations that did believe in a "black sun".  Much of the theory would depend on what the light source of the moon actually is, whether it's merely a reflection of the sun, and there's a significant body of evidence demonstrating that this cannot be the case.

One problem with eclipse theory is that the line put out by Neil de Grasse Tyson that the only thing that can produce a round shadow is a sphere.  That's actually incorrect when the shadow is also ON a sphere.  When a sphere casts a shadow onto another sphere, the resulting shadow is in fact a straight line.  This has been demonstrated by FEs with models.

Another problem is with the selenelion.

I'll also have to dig up a video I saw of a solar eclipse viewed from a plane, and the demonstration that the shadows created would be impossible given the model where the sun is millions of miles away.

And yet another problem is that the umbra (or main shadow) of the moon on the earth is way too small.

NASA tried to explain it away by claiming that this is the "correct" model.



But this is utterly ridiculous.  Given the alleged distance of the sun from the earth and the moon, it is NOT that much larger than the moon.  In fact, the relative distances and sizes of the two is what they use to explain the fact that they appear to be roughly the same size in the sky, with the sun being 400x larger but also 400x farther away.

By the time the sun's rays get to the earth from those distances, the sun's ray's are a small fraction of a degree off completely parallel with one another.  So this picture here is a total lie.  Nevertheless, I suspect that the scale of the moon is a bit off as well, given the alleged distances involved.  So I think a real objective study of the matter needs to be performed.  Yet why are such studies lacking?  It's because every operates on the ASSUMPTION (begging the question) that the heliocentric model is correct, so they're more about coming up with narratives to explain away the various phenomena that seem to run counter to the globe model rather than attempting to look at them objectively.

One interesting point in the above debate that was ultimately won by the Flat Earther is that the Glober pointed out a consistent declination of Polaris in the sky as you move south (that IMO also explains what at a certain point you can't see Polaris, because it beings to converge with the horizon since it's not that far away).  But the point made by the FE is indisputable.  This declination is perfectly linear with the distance moved.  But if we're on a globe, it would certainly NOT be linear, but more geometrical.  So this demonstrates that the declination with movement is taking place over a flat plane.  It's just like with the 8" per mile SQUARED.  It's not 8" per mile, but 8" per mile SQUARED, a geometric progression to to the nature of a sphere over a ball, whereas 8" per mile would be a linear progression.

What do people say the radius of the Earth is? about 3963 miles and flat Earthers can't find an edge?

When the Earth is accepted as a sphere, a precipitately condensed object, anybody can find another edge right where he is. All these edges are final too but the flat Earthers never tell where the edge is or the edges are, or where anybody might possible fall off.

Brahe was a geocentrist so he had that part correct, imho, but he's got this wrong. What does one think is predicated of space as pure space?

Well, besides some nature of inherent connection and universal sameness, there is direction, for one, which seems predicated of space. Direction and some extent or extensiveness, also the properties of balance and more or less, which are like quality and quantity. In fact, it seems evident that there are in total six cosmic directions in space. Descartes as well as Euclid could have it described by the origin at X, Y, and Z. Space itself is not flat except in a restricted limit of two dimensions only in a plane, but pure space is always the same and more, so the whole picture of it is as a sphere, especially when it comes to pure space.

When people make it to the mountain top and really breathe in the air, it's not a flat experience. It's 3-D and spherical. Inspiration and respiration are not flat and neither are the Heavens which can even be said to represent divine inspiration.

I was providing information provided by a professional in the know who's expertise presented prior to the layers of various contradictory arguments built up over time.  As far as the ground being flat, earth is thoroughly and demonstrably 3-D with mountains and valleys over a surface.  Seems globers lose their depth perception in this discussion and think we're saying earth is flat as a piece of paper.   

Okay, so how many sides are there to the flat Earth?

The only side that matters is the side that humans live on, but that doesn't mean earth hasn't got depth, at the very least 8 miles deep and probably a lot deeper.  8 miles is the deepest human beings have ever explored but the oceans are incredibly deep. And scripture talks about the 'great deep' and also says that earth has foundational pillars upon which God founded the whole thing, so there's no doubt earth has a lot of depth. There's also no doubt earth has mountains and valleys and hills.  It just isn't a globe.   

The humans all live on one side?

Yes, top side.

If the Sun lights up the face of the Earth, and all people live on one side, where does the Sun go at night?

It is over another part of the earth as it is above the earth circling around it.

The only side that matters is the side that humans live on, but that doesn't mean earth hasn't got depth, at the very least 8 miles deep and probably a lot deeper.  8 miles is the deepest human beings have ever explored but the oceans are incredibly deep. And scripture talks about the 'great deep' and also says that earth has foundational pillars upon which God founded the whole thing, so there's no doubt earth has a lot of depth. There's also no doubt earth has mountains and valleys and hills.  It just isn't a globe. 

It seems to me the Earth has uniform depth to everything on the surface. About 3963 mile radius to the center.

Besides depth, consider the convergence of it, since depth is a kind of convergence. In "Meteorology" Aristotle mentions three principal kinds of motion: from the center, to the center, around the center, that exist in the elements and their patterns. The weather is full of patterns of convergence and the Earth is like an element that formed through convergence and condensation out of these three basic elemental motions, and that's why it most naturally was created as a sphere.