You absolutely can argue the Earth isn’t round. You won’t win the argument, but it’s an acceptable idea to challenge. Indeed, having to defend the position tha

You absolutely can argue the Earth isn’t round. You won’t win the argument, but it’s an acceptable idea to challenge. Indeed, having to defend the position that the Earth is in fact round can help you gain understanding and have confidence in your conclusion. Not to belabor the point, but the idea that the Earth is flat is actually natural. It seems to be flat based on our senses. I think it’s a great teaching moment about how things are not as they seem.