That direct connection to the natural vibratory world may be in decline, but a different vibroscape has arisen. Modern cellphones buzz against our skin and fingertips, alerting us of breaking news, upcoming events, and social attention. Our devices use vibrations to connect us to the world beyond our bodies, extending our Umwelt beyond the reach of

We have used technology to make the invisible visible and the inaudible audible. This ability to dip into other Umwelten is our greatest sensory skill.

For him, to sit or lie upon the ground is to be able to think more deeply and to feel more keenly; he can see more clearly into the mysteries of life and come closer in kinship to other lives about him. The earth was full of sounds which the old-time Indian could hear, sometimes putting his ear to it so as to hear more clearly.”

Could pain exist without consciousness? If you strip the emotion out of pain, are you just left with nociception, or a gray area that our imaginations struggle to fill? Perhaps more than for other senses, it is easy to forget that pain can vary, and hard to conceive of how it might.

Whenever an animal moves, it unconsciously creates a mirror version of its own will, which it uses to predict the sensory consequences of its actions. With every action, the senses are forewarned about what to expect and can prepare themselves accordingly.

Evolution has pushed the nervous systems of insects toward minimalism and efficiency, cramming as much processing power as possible into small heads and bodies. Any extra mental ability—say, consciousness—requires more neurons, which would sap their already tight energy budget. They should pay that cost only if they reaped an important benefit.

“No robot is as sophisticated as an insect.” Her point is that insect nervous systems have evolved to pull off complex behaviors in the simplest possible ways, and robots show us how simple it is possible to be. If we can program them to accomplish all the adaptive actions that pain supposedly enables without also programming them with consciousnes

Distinguishing self from other isn’t a given; it’s a difficult problem that nervous systems have to solve. “This is largely what sentience is,” neuroscientist Michael Hendricks tells me. “And perhaps it’s why sentience is: It’s the process of sorting perceptual experiences into self-generated and other-generated.”

He couldn’t see any of them, but he knew there was a bustling electric world below his feet. “It was a moment I can still close my eyes and go back to,” he tells me. “It was the most amazing experience I’ve ever had, and I’m so sad I’m not there right now.”