I would like to learn how does that issue illustrate the non-factor of geography in shaping the regional culture.
I didn't say that well, which is emblematic of my experience with Chinese history. Drazi's Razor (per Eudaimonist) seems fitting.
My point in the paper was that if geography is the key, it seems to be pointing to contradictory conclusions. As such, it couldn't all just be about geography. Further, while I agree with your comment to Eudaimonist that geography is more than just the lay of the land, one must also be careful not to use the term too broadly, or it becomes useless.
So, with respect to tea, I focused on 2 basic things. First, there are regions of China where tea grows well, and there are regions where it doesn't grow well. Even so, in the regions where it doesn't grow well, tea culture is pervasive. In fact, in those regions - some of them difficult to access - they pay a great price to ship tea in. So, in those places, it is not
because of geography that tea prevails. Rather, it seems to be
despite geography that it prevails. It is more the binding power of the tea culture and the political advantages that motivated the central government to use it for control.
Second, I found some small minorities in geographically unique areas that had developed a tea culture that is different than the main Chinese tea culture. Here it seems geography
did play a role, but not to unify China - rather to distinguish various cultures. And what was the reaction of the Han (the majority culture)? They were pretty successful in stamping out the minority culture (though in a very interesting way (1)). Their success came from their overwhelming numbers (my army is bigger than your army), not really because of what I consider to be geography.
Again, yes geography played a role, but I think it's a reach to give it too much credit for those 2 reasons, which I would summarize as:
1) In some cases Chinese philosophy was spread by cultural insistence in spite of geographic difficulties.
2) In some cases Chinese philosophy simply came along for the ride as part of Han military might, which was used to stamp out the small pockets where geography did play a strong role in cultural development.
Footnote 1: One interesting tactic of the Han was to "celebrate" the minority cultures in China. A special day was set aside when minorities were allowed to wear their native dress, perform their native customs, etc. The interesting side effect of that is that these minorities are then implicitly relegated to a caricature of themselves. They get one day a year when all of China entertains themselves with these provincial customs, and then goes back to the "proper Chinese" way of doing things the rest of the year - they put minority culture back in the drawer and ignore it - much like the west has done with Christmas, Easter, All Saint's Day (Halloween), etc.
