I haven't fallen out, I've just given up.

I spent too much time yesterday evening offering a differing perception, based in part on what I've seen from the train window. I've never claimed a theory, or argued a link, in fact I've done the exact opposite. But throughout the discussion, I was told that I was wrong. I wasn't told that someone disagreed with me or had a different opinion. I was told flat out that I was wrong, my perception was wrong and what I was suggesting was impossible, based on angles and alignments. I think that's quite rude, and doesn't encourage discussion. By all means disagree with me, or correct me if I'm factually incorrect. But don't tell me my perception is wrong. Perception can't be wrong, it's wholly subjective. You can't measure perception.

You can go on Google Earth and look at satellite photos of the Sahara. You won't see any cities, there aren't any. And yet in certain circumstances, travellers can see them there, through an optical illusion, a trick of perception. They can be photographed. It can be proven that they are visible. But there is no physical form, no reality of a city. Does the lack of physical form or evidence of a city make the perception of one "impossible" or "wrong"?