If I were a Scot, I'd be leaning toward voting for independence in next month's referendum, on the logic that the advantages of self-government outweigh the drawbacks of being a small state. How does that logic apply to Britain's choice about remaining a member of the European Union?

The same kind of calculation applies, but it's more complicated than the Scotland-U.K. question. To begin with, of course, the U.K. is still an independent state. It has surrendered some powers to Europe, but for most purposes, it doesn't have to leave the EU to achieve self-governance.

Trouble is, the EU is intent on testing the meaning of self-government. It's hard to know what the EU will be, say, 10 years from now. It was conceived as a work in progress — formally committed to the goal of "ever closer union." The EU's constitution is unusual: Rather than describing a settled design, it commits its members to perpetual constitutional innovation.