Adam Gopnik addresses the question:
Irrationalities are as essential to dissolving unions as they are to maintaining them. Scotland, which is just now voting on independence, is also, we’re told, acting against its self-evident economic interests—or, at the very least, acting with huge, unfunded optimism. Once again, as is so often the case in the twentieth century, the atavistic thrill of nationalism is ballooned up by the blithe certainty that it will somehow magically lead to a progressive paradise. As Canadians alone remember, the province of Quebec, in two referendums, did, or came close to doing, the same thing with the same unfounded belief.
It is easy to say that such a move makes no sense, but nationalism is almost always a more powerful drug than is the promise of continued prosperity. The irony is that many Scottish nationalists see the larger European Union as their alternative to the apparently stifling British one, though E.U. membership for an independent Scotland would be far from guaranteed, and would affect everything from the politics of emigration to the price of scotch. Nationalists in Quebec believed something similar, holding out the dubious hope that the United States would be a welcoming market for and partner with a monolingual French Quebec in ways that Canada somehow was not.
Michael Brendan Dougherty blames the EU for the increasing nationalism across Europe:
By creating a federated superstate with its own defense policies, currency, and central bank, the EU takes off the table some of the hardest questions a separatist or secessionist movement has to answer. The EU does a lot of the work of a nation-state for them. To some degree, extant and aspiring nationalisms are free-riding on an official internationalism.
The EU tends to be extremely generous in dignifying minority languages, regions, and even political movements with some kind of official status. Latvian, Irish, and Maltese are all recognized European languages, but good luck finding four million people who speak any of these fluently. Still, this kind of recognition is important to nationalists looking to maintain some kind of identity in the face of an overwhelming, powerful neighbor, or globalism more generally.
But Nicholas Shackel refuses to label Scotland’s Yes voters irrational:
It is certainly true that a lot of the time for a lot of people acting rationally does amount to acting prudently. But it is not generally true. Rationality requires acting in accord with what one care’s about. If you care most about your best interest it would be irrational to act against it, but when that isn’t what you care most about then it isn’t irrational to act against it.
So then the question of the rationality of voting for Scottish independence comes down to what the person voting most cares about. They may care more about freedom of association than about their self interest, and if for them not being ruled by the British state but being ruled by a Scottish state instead satisfied what they value in freedom of association, then voting for independence could be perfectly rational despite it being against their best interest.
Jonathan Tobin argues along the same lines:
Whether it is true or not, a great many Scots believe themselves to have been oppressed by the English and to have had their nation stolen from them. They may not be mad enough to wish to bring back a descendant of the Stuarts, but the longing for the return of Bonnie Prince Charlie, the last Stuart Pretender who led the Scots to disaster at Culloden in 1746 and then was forced to flee to European exile, left its mark on the country’s national consciousness. That fueled the romance of a separate Scots identity that was never entirely extinguished even during the heyday of Scottish involvement in the enterprise of the British Empire. So long as these myths are influential and can be buttressed by modern grievances, however insubstantial, independence will always have a constituency that will consider it worth a great deal of inconvenience if not hardship.
(Photo: An independence supporter sports a Scottish Saltire tie, badge and rosette as he stands outside a polling station on September 18, 2014 in Strichen, Scotland. By Peter Macdiarmid/Getty Images)