Being in two places at once is tricky if you aren’t an electron. But people seem to manage it. Like most of us, I’ve had friends ask me what I was doing at such-and-such place the other day — only to become a little confused when I explain I wasn’t there at all.
This is the work of a doppelgänger. The product of folklore, formerly an image of death, has become fodder for movies and literature; Jordan Peele’s Us comes to mind. But beyond the idea of an evil twin, most people understand the doppelgänger as being a stranger who looks so similar to you that others mistake them for you, or vice versa.
It’s been said that each of us has seven lookalikes out there, but how common are they really? Mathematicians and geneticists alike find the question difficult to answer.
The first problem is that there’s no strict ...
