The modernists seem to have been correct in thinking that hats stood for old hierarchies; I suppose I am post-modern in thinking that this is amusing but not important. And yet, the hierarchies aren't gone, and the modernists were certainly wrong in expecting them to vanish.
I can't tell where Seal started re hats. I think he was with the postmodernists, with the hats-are-funny mindset, but he was familiar enough with Turkey to connect its repeated politicization of headwear with the strain between traditional, isolated, religious communities and the bonfire of tourism. Fezzes are used to lure tourists, but it has been illegal for Turks to wear them since Ataturk. Before that, the fez was the headwear of the Ottoman Empire.
Seal actually finds someone in a very quiet town who is still wearing a turban, and claims to be surprised that they have been made illegal: in favor of the fez? We are to wear fezzes? No, that was a century ago, fezzes are now also illegal?... Someone's leg is being pulled. A few Turks determinedly wear the fez, just not where someone can write about them. Seal never really gets anyone to say why, or what they mean to the wearers or non-wearers.
Their most surprising and evocative appearance is on statues of the brief Commagene empire, weathered on Mount Nemrut for almost two thousand years. These are more conical than the modern fez, but apparently the historical development from conical to flat-topped is documented well enough. But the Commagenes didn't last long or conquer anybody, so why the fez, in either shape, became the hat of the Ottoman Empire is not very clear. The city Fez has fez-makers, but calls them tarbooshes. Dervishes wear similar hats but a different color. Identifying them with the Phrygian cap of liberty, or at least the pileus, is irresistible for an armchair classicist, but the people who actually might wear them assert that the fez is important because Islamic, not because Ancient Greek. The Ancient Greeks apparently thought their version was slightly Persian.
Standing on Mount Nemrut, by the speechless stones, Seal looked East and West, North and South, over the Euphrates, down to Aleppo. His trip to the mountain was beautiful but complicated, with the kind of scenery that you only get over dangerously active geology. Seal takes this humanistically; the west of Turkey is as good a boundary between Europe and Asia as is the Sea of Marmara, or a better one, since the ocean is naturally a trade-route and the mountains a barrier. 'Boundary' can combine the seeming paradox of the fez, and of Turkey's reactions to it, and Turkey's enormous strain between modernizing and tradition, and the pulled-together-pushed-apart tragedies of all the overlapping, subdivided, sub-nation-states that still inspire wars here: the Kurds, the Armenians, Cyprus. Maps drawn by the Ottoman and British Empires illuminate current policy.
It's a little easy, as an American, to dismiss the Ottoman Empire, because by the time the US was acting on the world stage the latter was a very `sick man of history'. We see what's definitely Europe, and what's definitely the East, and the less-well-defined parts, we figure, just have to make up their minds. But the Ottoman Empire was brilliant and unified and certainly long-lasting enough to be a thing in itself; so not only do the various nations into which they are now divided have parts that would like to go East-ish, and parts West-ish, but loyalty to an old unity that the East and West aren't even really conscious of. It's easier to remember how important it was if you like the history of the 14th-16th centuries, when Europe was a pushy younger sibling (and large chunks of it Ottoman, to boot; `anyplace that cooks with paprika', I have read).
In the twentieth century, though, even the nations into which it had been divided were playing well below their historical standard, and purely humanistic explanations aren't enough. That glorious scenic geology is close to oil (and rather a lot of other resources, in some places. The deeps of the earth have been cooked and sorted and rammed up high). I can't imagine how history would have turned out had the fossil-fuel age started when the Ottoman Empire was at its height; but as the excellent, excoriating, History of Oil by points out in passing, the sinking Ottomans got dissected because they were between various European powers and oil, oil, oil.
I squint at the map of Georgia and South Ossetia and it's a little obvious that this is still going on. The headlines are clearer yet; "Oil rises on Georgia fighting", "Georgia's oil pipeline is key to U.S. support."
Georgia, over the last half-millenium, has been under Ottoman, Persian, Russian, USSR, and several kinds of independent rule. I haven't found a serious source on their hats, but the one I do have shows a wide array. Resources and geography move people around; people settle and intermarry; wars over resources redraw the boundaries; and who gets to define the national hat?
Find in a Library: A Fez of the Heart, Jeremy Seal, ISBN 9780156003933.