Day and night on the flat earth

This is an issue I keep coming back to, in part because it's gaining ground in "evangelical" scholarship, and in part because it's open to different lines of attack. In this article, Paul Seely attempts to document a monolithic view of the cosmos in primitive, pre-scientific cultures: "The Geographical Meaning of 'Earth' and 'Seas' in Genesis 1:10." WTJ 59 (1997) 231–55. The point I've always made is that the textbound orientation of scholars who support this view has the wrong starting-point. For one thing, there are ancient pictorial representations of the cosmos that are inconsistent with other pictorial representations, as well as inconsistent with observable reality. 

Scholars who espouse flat-earth cosmography disregard the observable world in which ancient people lived. Let's recap one example I've given. The phenomenon of the seasons makes no sense on a flat-earth model. On that model, there should be one season year round. It's a static system. There's no room for variation in the angle or duration of sunlight. As a boy, I used to notice that sunrise and sunset lay further apart on the horizon in summer and closer together in winter. 

Now let's take a related example. The length of day and night isn't just variable by season but latitude. At one extreme are equatorial regions while at the other extreme is the Arctic circle, with polar days and polar nights. 

It might be objected that ancient people lacked a comparative frame of reference to notice the variation. They lived in the same area. 

But that's not true. There were ancient mariners who sailed up and down coastlines. They were in a position to observe rapid changes in the duration of day and night as they sailed up and down coastlines. Changes that didn't correspond to seasons, but location. Once again, that's incompatible with a flat-earth cosmography. 

Ancient mariners would disseminate stories about their adventures. People would be interested in stories by ancient mariners about their discoveries. 

My point is that even from a prescientific standpoint, there were multiple lines of evidence that falsify flat-earth cosmography. Some of these are blatant while others are more subtle. Some require you to think about the incongruence. Not everyone is thoughtful. But some people are.