Not ethnic diversity, but lack of a shared identity. Outside of the major cities, the people living in the middle eastern countries were more loyal to their tribe and village than whatever power happened to currently be in charge of the country. That's also why it seems like so much religious extremism comes out of the middle east; a shared religion is one of the only things in common among the people living there, so any calls to action normally use religion as common ground to bring people together.

This is saying people are loyal to their tribes, and view the government's interests as unaligned with those of their tribe, presumably giving rise to a lack of common cause in something that a government might foster like scientific development. But if "tribe" were synonymous with "ethnic group" then you'd actually be saying that multiple ethnic groups sharing a government are a cause (not necessarily the only one) of scientific stagnation. But it sounds like you're not. So what defines these tribes if not ethnic group?

I think implicit in your argument is a belief that utility ("interests") trumps identity ("who we are") in loyalty dynamics. I think that belief is.. not universal..

I believe the OP was suggesting that externally-imposed boundaries can hold areas in an unstable state for long periods of time, but when they are gone there is unrest that takes time to achieve a stable society and that scientific progress is best achieved when people arent worried aobut their food/safety/corrupt warlord.

I think it may be more useful to think of "tribe" or "clan" as a political organizations that form the base of decentralized governments than ethnic groups, since many tribes can exist within any given ethnic group, and many ethnic groups can exist within geographic areas governed by decentralized bodies.

So, 'tribe' here doesn't necessarily mean an ethnic group. Depending on scenario, it might really just mean 'village'; in some sense, large regions of some countries never _really_ became part of the nation at all.

A hypothesis: not diversity, but division. Consider the Kurds; their traditional territory is in about 5 modern countries, and they don't particularly get along with any of their governments.

That isn't directly related to "scientific development", but that, like most things, relies on economic and political stability.

The theory rsynnott is referring to is what you'll find if you google "colonial borders"

For example, some people have pointed out when European colonialists set borders, they were more concerned with natural resources and the opinions of competing colonial powers than with what the locals thought of the borders.

Some people go further, thinking in at least some instances colonial governments intentionally created the situations for internal strife, as doing so could make regions easier to control. Set the borders so that area is 75% Religion A, 25% Religion B then you can appoint powerful local deputies from Religion B. Your powerful deputies will never support a popular revolution, as it'd make them lose all their power.

Later the colonial power leaves, but the borders stay in the same place - along with a generous helping of resentment and fear between the groups - and the stage is set for internal strife, political blocs formed along ethnic lines, and so on.

And if European colonists produced messed up borders, why couldn't Ottoman colonists have caused the same effects?

That doesn't mean ethnic diversity causes the problem - but there are several elements that set the scene for problems, and ethnic voting blocs are an easily measured component, though not sufficient on their own.

The Ottoman situation was arguably even messier, because the Ottomans had one set of provinces, and then the Mandatory authorities had a somewhat different one.

National identity. Colonialism tended to produce totally novel countries, and often who was put in charge was largely random.

It’s not just a colonialism thing either; in Europe wars often resulted in territorial change; the territory was then the cause of the next war.

Could you elaborate? In both Ireland's and Korea's cases, despite their relatively small size, both nations have notable scientific output. What's different about them?

Both do NOW. In Ireland’s case, honestly, we probably have the EU, a massive stabilising influence, to thank for that, along with treaties that make the border a day-to-day non-issue (you can walk across it without noticing). In the case of Korea, the opposite happened; the border became so fixed due to external influence that there wasn’t much anyone could do about it.

Dublin has long been a cultural center, since early Christianity, but modern Irish science benefits hugely from the tax incentive to move Pfizer there.

South Korea is the successful planned economy, like Singapore; on paper it's an open economy, and people are free to start businesses, but the top level is heavily coordinated between the government and megacorps. It was a military dictatorship for years while growing at over 5% a year. https://en.m.wikipedia.org/wiki/Park_Chung-hee

Maybe national identity is the issue, rather than ethnic identity. In Japan's case, they had continuity of government and a professional bureaucracy.