Sociological ideas can come from all sorts of places. Here how a French receipt for toothpaste provides insights into the unity of the European Union:

Harrington had spent her senior year of high school in France and had fallen in love with a specific toothpaste flavored with a lemony-minty herb called “verveine.” So she went to the nearest pharmacy, bought the place out (all two bottles worth), and forked over her euros.

But when Harrington looked at her receipt, she saw something that looked out of place. Below the price of her toothpaste in euros, there was a conversion statement that said 1 euro is equal to 6.5597 francs.

Handy? Well, sure, until one remembers that France has been on the Euro since 1999. That gives people more than a decade to practice converting euros to francs.

Most people would probably forget about this cultural oddity as soon as they crammed the receipt into their back pockets. But Harrington is an economic sociologist at the Copenhagen Business School, and decided to dig deeper. What she found was that this little line on the pharmacy receipt was indicative of larger identity issues in contemporary Europe.

With the advent of the European Union and a common currency, citizens had to reconcile their national identities with a new continental identity. The process has been far from frictionless — not only do many French people still talk about prices in terms of francs, but Germans still speak in terms of deutschmarks (and they don’t even have dual pricing receipts).

Harrington says the current debt crisis has revealed cracks in the spirit of European collectivism “because it was never a seamless whole to begin with.”

This story suggests a kind of intellectual curiosity I would guess a lot of sociologists would want to instill in their students: how might you see the world, including pharmacy receipts, from a sociological perspective? Within the field of sociology, Harrington would have to build upon this single piece of evidence. In order to draw publishable conclusions about “European collectivism,” she would need to draw upon a broader dataset that would have demonstrated patterns of behavior.