Fate and Destiny: a philosophy thread

[Alex]

I believe we create the world around us. My husband challenged me on that, asking me if the world really was flat and the center of the universe when everybody believed that to be true. I couldn't answer that, though my initial thought is that yes, somehow, it had to be flat.

For me this raises a question. I'm curious how you would answer (though, of course, you don't need to):

What about the, at least, 2,000 years when all educated people knew the earth is round (the ancient Greeks had competing calculations of the circumference, some of which were amazingly accurate) and the uneducated believed it to be flat?

Is the reality creating require a shared belief or an individual one?