0. ‘Europe’ and ‘Asia’ are unhelpful, outdated concepts. There is only Eurasia.
This is really the only acceptable resolution to the question of where one continent ends and the other begins. There really is just one continent there (though be sure to note: further continent-merging is still appropriate). Just take a look at a world map without any human-made borders on it: does it look like there’s two continents here? Whereas North America and South America (as well as Africa and Asia) look pinched enough that one may consider there to be two landmasses really involved (and now there’s actual water dividing them, as much as this water really shouldn’t count by most standards), the connection between Europe and Asia is massive—like, largest-country-in-the-world massive. Europe/Asia even exhibits a property that North America/South America and Africa/Asia don’t have: the bulk of Europe and Asia aren’t even geologically on different plates. Geologically, it makes more sense to consider India a different continent from Asia than Europe (as well as Arabia, and so on).
So how have we as a society managed to come to decide that Europe and Asia are separate countries? It turns out that it’s because our impeccable education systems have a couple of millenia of world geography updates to catch up on. Some ancient Greeks thought the Black Sea was an entire ocean (they’re not wrong—the Black Sea is, geologically, an ocean, but they thought it was an ocean on the scale of there’s-no-huge-swath-of-land-shortly-beyond-it), and therefore the land on this side must be a different continent than the land on that side of the bodies of water connecting it and the Mediterranean. Somehow, this provincial view of the world has managed to stay until the present day.
At this point, someone will inevitably bring up the argument that there are massive cultural differences between Europe and Asia, which justifies the classifying of Europe and Asia as two different continents. I invite anyone who thinks culture should define continents to make a case about India being part of Asia and the parts of Africa north and south of the Sahara being in the same continent, followed by where the boundary should really be drawn between North and South America, if there should really be just one boundary there, and etc., and then reflect a bit on how reasonable it is for culture to define continents.
So yes, we should catch up to dozens of generations ago and realize that there’s no good geographical, geological, or cultural reason for Europe and Asia to be considered distinct continents. With this, we should also throw away the inane arguments that happen about whether Russia is European or Asian as well as trivia facts like that Istanbul is the only city in the world that spans two continents, a fact that is as amazing as the fact that two is the only even prime until someone points out that seven is the only prime divisible by seven.
This having been said, some conventions of division between Europe and Asia still have merit when one digs far enough, or at least enough merit to be saner conventions than other ways of separating Europe and Asia. That’s what the rest of this blog post will be for.
1. The Central, South, Volga, Northwest, and Northern Caucasus federal districts of Russia are in Europe, and the rest of Russia is in Asia; Turkey is divided along the Dardanelles, Sea of Marmara, and Bosporus; Kazakhstan, Georgia, Azerbaijan, and Cyprus are completely in Asia
This is a well-defined split that fairly well traces significant geologic boundaries. If we have to designate two different continents, we manage to actually trace things that “get in the way” of going from one side to the other using this method. While doing so, it somewhat traces cultural separations that people sometimes talk about in terms of the Europe-Asia distinction, though it still doesn’t do anywhere near a good job of it.
2. Europe and Asia are divided by the Ural Mountains, Ural River, Caspian Sea, Caucasus Mountains, Black Sea, Bosporus, Sea of Marmara, and Dardanelles, and Cyprus is a part of Asia (or similar geologically-based definitions)
This is very much like the above, except it’s no longer well-defined. Where along the Ural Mountains does the split actually happen? At what latitude and/or longitude does the Ural Mountains stop being the boundary and the Ural River start? Is Novaya Zemlya in Europe or Asia? Given that Novaya Zemlya is geologically an extension of the Ural Mountains, that would mean this series of islands is split down the middle in continent classification, which is really weird. It also splits off a portion of western Kazakhstan into Europe, which feels rather cartographically unintuitive.
3a. Countries can only be defined as being part of one continent, and Kazakhstan, Turkey, and Cyprus are all completely in Asia while Russia is completely in Europe
This means that Europe is closer to America on the east end (at the Bering Strait) than on the west end, and that the geographical center of Europe is near the middle of Russia. (Also, Vladivostok would be a European city despite being east of Delhi, Beijing, Manila, and Seoul, and southeast of Harbin.) This seems like a vastly inferior definition, until one considers other ways of classifying countries as completely within continents.
3b. Countries can only be defined as being part of one continent, and Russia, Turkey, and Cyprus are all completely in Europe while Kazakhstan is completely in Asia
If all of Turkey must go in one continent, either designation seems fine, as the resulting line of division is not too unreasonable either way. (Hatay will look really weird.) It does start mattering if one decides to put Cyprus in the opposite continent than Turkey, which we’ll address later in this list.
5a. Countries can only be defined as being part of one continent, and Russia, Kazakhstan, Turkey, and Cyprus are all completely in Asia
This means that Kaliningrad is in Asia, surrounded by European countries. Apparently, however, the EU thinks that France’s outermost regions from French Guiana to Réunion can qualify as part of the EU, so maybe at least this sort of thinking is not alone, although the EU is also an organization nomologically (though as things look, probably not practically) predicated on the notion that Europe is a distinct entity.
5b. Countries can only be defined as being part of one continent, and Russia, Kazakhstan, Turkey, and Cyprus are all completely in Europe
If the Steppes of Central Asia and the Tian Shan become partly in Europe, the boundary between Europe and Asia has definitely been drawn very suboptimally. The Syr Darya becomes a transcontinental river. It’s perhaps arguable whether this is better or worse than Kaliningrad being a surrounded isolated exclave of Asia.
7. Definitions that place Cyprus in the opposite continent than the majority of Turkey
This makes the island of Cyprus part of the opposite continent than the closest landmass. If Cyprus is defined as part of Europe, this makes Europe become laughably concave.
8. Definitions that split Cyprus along the UN buffer zone
The UN buffer zone has nonzero area inside, exhibits an exclave complex upon intersecting Dhekelia, and has only existed for four decades. Defining Cyprus as being on two continents in this fashion establishes both Europe and Asia as neither well-defined nor likely closed nor even stable in the scale of the human lifetime. One that is trying to use this definition is likely trying to use culture to define continents, and we’ve addressed how quickly this train derails above.