Paper seems completely harmless, but deployed properly, it can be a serious weapon: paper cuts are just the worst.
It’s all to do with nerve endings. To start with, there are lots more pain receptors embedded in your fingertips than almost anywhere else in your body. So while a paper cut on your arm, or thigh, or ankle might still be annoying, it would probably be more trivial than the intense fiery quality that finger-based paper cuts tend to have.
This actually makes a good deal of evolutionary sense. Fingertips are how we explore the world, how we do small delicate tasks. So it makes sense that we have a lot of nerve endings there. It’s kind of a safety mechanism.
To the naked eye, it might seem as if a paper's edge is fairly straight and smooth. But if you were to zoom in, you’d find that paper is more akin to a saw than to a blade.
And paper cuts are typically shallow – but not too shallow. They’re deep enough to get past the top layer of the skin, otherwise they wouldn’t hurt. The top layer of skin has no nerve endings. But they don’t slice that deep into your body, which is perhaps why it’s puzzling that they should hurt so much. A deeper wound would result in bleeding. The blood would clot and a scab would develop, beneath which the skin could go about healing free from the continuedassault of the outside world. But the shallow wound of a paper cut doesn't offer such protection.
Without the cushion of blood, pain receptors are left exposed to the elements, and unless you quickly bandage your paper cut, those neurons will keep on sending the alarm bell. That, after all, is their job.
Unfortunately, each of us is going to face the prospect of enduring a few paper cuts as we go about our lives. Luckily, a thousand paper cuts would really really hurt, but it probably wouldn’t kill you.