One argument that has been put forward against voting for Scottish independence in the Scottish referendum is that it would be irrational for Scotland to break free of the rest of Great Britain. The grounds for this claim are that the Scottish economy would be significantly worse under independence. This is an empirical claim and for the sake of argument I am going to grant it. What I am interested in is whether, supposing that to be true, it would in fact be irrational. There are a number of things seriously wrong with this inference.
The first thing wrong is that Scotland is not the kind of thing that can be irrational, just as it is not the kind of thing that can be rational either. Perhaps those advancing the claim mean instead that it would not be Scotland but rather the Scottish people that would be irrational. ‘The Scottish people’, however, is ambiguous. If there is such an entity as the Scottish people, it is no more the kind of thing that can be irrational than is Scotland itself. The phrase might mean the people living in Scotland: again, a plurality of people cannot be irrational. What can be irrational are the individual persons who compose that plurality. So to take the claim seriously we must understand it as the claim that each person in Scotland who wishes to live under a Scottish state rather than a British state is irrational because the Scottish economy would be worse.
This argument, therefore, is essentially an application of the economic model of rationality (applied in a particular way—there is a way of understanding that model in terms of revealed preference that might fit with what I am about to say, but that is not how the argument is being made). Rationality is acting in accord with one’s best interest and it is in one’s best interest to be in a better rather than worse economy. I shall grant the latter conjunct, ceteris paribus. The former conjunct is false. 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.
For me, what would be wrong would not be the rationality of voting for independence on that basis, but caring in the wrong way about which state you are subject to. The freedom of association that is valuable, whilst infringed by being ruled by the British state, is not so infringed by it being the British state rather than a Scottish state. To think otherwise is to care in the wrong way about national identity. States are mere instruments for protecting our rights and solving some coordination problems. Granted that states are mere instruments brings back into view the significance of independence resulting in a worse economy.
Even though many not too bad states have grown out of particular cultures (the best parts of the British state are those respecting and restrained by the civil societies of the Scotland, Wales, Ireland and England), ideally states would not become enmeshed in cultural identities at all. Unfortunately, those arguing for independence seem to me to be doing so on precisely such grounds. A danger proved time and again in history is that those people who do wish to enmesh states in cultural identity also want to run the state in a way that does not protect our true rights of freedom of association.
So I do not think that anyone voting for independence can be convicted of irrationality on the grounds that have been advanced. I do think they may be mistaken in what they value or their understanding of what they value. But respecting freedom of association as I do also requires respecting that if they want to secede they have every right to do so and it cannot be legitimate to stop them.