I've clicked every link in this thread and listened to everything and I think I've heard everything he's publicly said on the subject including a few different Road Trippin' podcasts. I have heard nothing that leads me to believe he 100% thinks the Earth is round and nothing that sounds like he was intentionally trolling when he said it.
This is my theory:
He's trying to make a broader point. I'm not an astronomer or an astronaut. I haven't done the work to understand that the world is round, aside from understanding the basic principles. I believe that the world is round because astronomers and astronauts and other educated people I trust have told me it is. But because I haven't done the work to understand it myself, it would be incorrect to say I know this to be true. Really, I just believe it to be true.
I think Kyrie is trying to make a point about the information we take for granted. There are a lot of things we talk about like he know them to be true but really we just believe them because people we trust have said so. I've never seen an atom but I believe they are the building blocks of the universe. I don't know that gravity exists but people a lot smarter and more educated who have done more work on the subject have explained to me that it is.
I think Kyrie is just more apt to think of these things as more flexible rather than take it for granted that it is 100% true.
Thats my theory, anyway.
It's a good theory, but it just seems like a strange topic to make that point on. Perhaps he chose it because it's such an obvious thing.
Minor correction on gravity: You KNOW gravity exists, just not why. People a lot smarter than you have not shown much to explain why, but you didn't need them anyway to know it exists.
Do we, really?
The theory is that we know gravity exists because we are always being pulled down towards the ground - for example if we jump up, we will eventually come back down. If we throw something up, it will fall back down.
But how do we KNOW that this is because of gravity? How do we know that it is the earth's gravitational pull that is pulling us towards the centre of the earth causing this? How do we know that it is a force pulling us towards the centre of the earth? How do we know it isn't actually some type of force that the earth atmosphere is pushing down on us with, that's simply pushing us towards the ground?
Why is it that if we set a leaf down onto a pond, the leaf will float on top of the water rather then being pulled down? The assumption we'd make would be that the leaf Is less dense then the water, and hence the water is acting a force on the leaf that is pushing it upwards - and this force must be greater then the force of gravity pushing downwards, right? I mean that's the explanation I just popped out off the top of my head, because it makes sense.
But then how come if I get in to a swimming pool of water, I will float down to the bottom? Gravity pulling me down, right? But if change position so I am resting on my back, then I will actually float. How is that? The water density hasn't changed has it? My mass/density hasn't changed. Why am I now seemingly ignoring gravity just because I've changed the position of my body?
Obviously there will be a scientific explanation for this, I know there will be - it's probably really simple too. But that will be a scientific explanation that somebody else has theorised or proven. It's not going to be something that I have somehow proven myself.
How about a bouncing basketball. The air pressure inside is able to allow the ball surface to compress, then expand back out, which then poduces enough force to overcome the force of gravity and force the ball back up again? I'm sure that's true. But that's just a theory. Unless I can find some kind of device that can measure the amount of force applied on the ball constantly (while it's dropping, as t's bouncing back up, etc) so that I can prove it has more than 9.8 m/s force acting on it whe it's bouncing back up (enough to overcome gravity) I'm just making assumptions here.
So technically, do I KNOW gravity exists? Not really. But I believe it without any doubts at all.
So his points are fair if that's the argument he is trying to make. The average human actually KNOWS very little about anything. The vast majority of what we consider to be "knowledge" is really just a see of information we have read from others be it via studies, from conversations, from blogs, etc. Very few of us could actually prove first hand half of the stuff we THINK we know.