On the eve of Brexit, some thoughts on passports:

• They let you cross invisible lines on the ground.
• Everyone only gets one (the rare person with two is envied, three or more make you a character from a spy novel). Every few years you go through a ritual in which the old one is destroyed following a certain protocol, and you're handed a new one.
• They have invisible information embdedded in them
• We hand them to border police sometimes, but I don't really know what they look at: The picture? Do they how tall you are? Do they have some way of visually checking the passport is genuine?
• On a related note, what do automatic passport gates do? Presumably they could read all the information they need from the chip inside the passport, but instead tey make you open the passport and press it onto a surface for what feels like forever — what is the camera looking for? All we know is that if you have the right passport, the gates will open.
• Some of them are more powerful than others (although power is vaguely defined).
• Rich people can buy them.
• Poor people don't have them

Passports seem like the 21st century version of a magical talisman — they're ubiquitous, yet we have only vague ideas about what they do and how they work. Perhaps in line with the end of the enlightenment.