Pain may be the most immediate and undeniable of human experiences. And yet it’s not obvious what it is, or where it comes from. Aristotle thought pain was basically an emotion, located in the heart. Ancient Egyptian physicians argued pain was more of a sensation, and nudged its source up to the brain. By the 19th century, science was starting to get the hang of the nervous system, and proposed there were essentially “pain organs” that existed to convey pain signals from the body -- say, your stubbed toe -- to the mind.

These days, scientists understand pain to involve all that stuff – emotions, nerves, the mind – all at once. It’s a complex experience, giving rise to pain in limbs that aren’t there anymore, to changes in brain circuitry and strange, super-senses, and even to subtle, almost lyrical characteristics in something as nasty as a bee sting.

Pain may be the most immediate and undeniable of human experiences. And yet it’s not obvious what it is, or where it comes from. Aristotle thought pain was basically an emotion, located in the heart. Ancient Egyptian physicians argued pain was more of a sensation, and nudged its source up to the brain. By the 19th century, science was starting to get the hang of the nervous system, and proposed there were essentially “pain organs” that existed to convey pain signals from the body -- say, your stubbed toe -- to the mind.

These days, scientists understand pain to involve all that stuff – emotions, nerves, the mind – all at once. It’s a complex experience, giving rise to pain in limbs that aren’t there anymore, to changes in brain circuitry and strange, super-senses, and even to subtle, almost lyrical characteristics in something as nasty as a bee sting.