If you limit yourself to that then I doubt you'll ever be convinced. The Earth is, in fact, a very large sphere and your senses are not capable of directly sensing curvature (or anything else) on that scale. You're like the ant that insists that the entire world consists of his tunnels and a 300 square foot area of your back yard.
How would you propose to do it?
That is a totally serious question. If you can come up with something that I am both capable of and can afford to do, I'll do it.
The fact that the surface of water is level (neglecting waves) is not disputed by anyone. As I just said a moment ago, your senses are not capable of detecting curvature on that scale. With or without atmospheric lensing, you could not detect the curvature of the Earth by simply looking at the surface of water.
A well known and very well understood fact of life. No way possible - IT IS NOT AT ALL POSSIBLE - to keep such a colossal lie from being discovered.
It isn't relativism in the sense you mean it here. The scales involved are not the cause of the distortion nor is there anything inherent about me that is causing a distortion as is the case with Einsteinian style relativism. In this case, it is simply a matter of scale. Your eyes are only about two and a half or three inches apart and, with good eyesight, have a resolution of about 1 arc minute. Something that is 8 inches long that is a mile away would have an angular size of .43 minutes, a little more than half of what your eye can normally resolve. And the closer things get, the worse the issue becomes because the Earth curves at 8 inches per mile squared. So the curvature a quarter mile away isn't 2 inches (8/4=2) it's four times smaller than that! It's only half an inch! The angular size of something .5 inches long at .25 miles away is only .1 arc minutes! No one could resolve that with their naked eye on their best day and thus to us mere mortals, the Earth looks very flat.
I do, however, agree with you that the curvature is not so slight that it cannot be measured. Not only is it measurable, it's information that is easily found and universally excepted by everyone who believes in a spherical Earth. The notion that flat Earthers don't simply go out and do the experiments required to disprove it is rather telling, don't you think? Such an easily debunk conspiracy could not possibly be maintained. And that's just on one tiny details of a web of lies so large and complex that it boggles the mind to even contemplate.
I think the limited person is the one who knows only one view of this, or any thing else for that matter. I have always wanted to know both sides of almost everything I ever studied. Some have said I know more about evolution than most people who believe in it. I started out broadening my understanding of cosmology by trying to figure out quantum physics, relativity, and multiverse theories. Flat earth was coming up on you tube a lot so I thought, why not take a look. And so here we are.
The most intriguing aspect of this is the curvature issue that is being disputed. The Nikon P900 with a 83x optical zoom is the camera of choice that's creating new energy for this movement. I can't wait to get one this summer and conduct some experiments of my own.
NASA to me has always been a sink hole of wasted trillions of dollars. The moon landing has always been to me, and many others, bad sci-fi movie making. I had believed that the moon was just to far away, to difficult to get to, and a worthless trip to a desert with no water and no air.
There are millions and billions of people that are absolutely convinced of evolution, global warming, relativity, Islam, and coming soon Globalism a.k.a., one world government, new world order. All of this is founded in the insanity that out of chaos comes order. So, I personally think it very possible that we have been deceived about the nature of the world. I used to think it was highly improbable, but not any more. Most, but not all, video for flat earth is very very good. But you have not taken them seriously as I have.
Just maybe, with new technology (especially cameras) in the hands of the average person, this cosmological big lie is finally being exposed. Maybe the Copernican cosmological model, along with everything that is built upon it, is a house of cards about to come crashing down.
--Dave