Theories that travel well
For the ancient Greeks, "theory" was grounded in direct observation.
Words are the stories we use to tell other stories.
When news reports from Chile mention the "curfews" imposed to preserve public order there, for instance, they're using a word that goes back to the 19th century to refer to periodic restrictions on people's movements – orders to stay off the streets until noon, for instance.
But before curfew referred to a ban on movement, it had a rather different meaning. It was an order to "cover the fire" (from the French couvrir plus feu). In medieval Europe it was the practice to ring a bell in the evening in a town or village as an order to bank one's fire for the night – "to cover it with ashes and use other means to prevent it from burning too quickly and yet at the same time to prevent it from going out," according to the Winston Simplified Dictionary, published in 1919 and brought to my fingertips by the magic of Google.
Medieval Europeans worried about untended fires burning out of control. Better to have a loud reminder for everyone to tuck their fire in for the night before they got too sleepy than to let people just drift off in front of the hearth.
And so it is that contemporary emergency management practice (Chilean earthquake) borrows a term that evolved from a medieval form of what we might today call community policing.
Sometimes one is fortunate enough to discover the history of a whole field of knowledge in a single word.
Theory, Dear Reader, is an example of just such a word. So I found out the other day in conversation with a political scientist who specializes in the emerging field of comparative political theory.