Your Body: The Missing Manual

Chapter 5. The Doors of Perception

Perception is a partnership between your sense organs—body parts like your eyes, ears, nose, and tongue—and your brain. Together, they collect clues about the outside world, such as how it looks, sounds, smells, tastes, and feels.

Thanks to the relentless force of evolution, every type of animal has its own carefully tuned senses, and so each lives in a slightly different bubble of perception. For example, although the presence of the earth’s magnetic field is obvious to even the daftest migrating bird, your body is completely unable to detect it. Similarly, your senses are closed to the ultraviolet light that guides bees to their favorite flowers and the electric currents that help sharks find their prey. Instead, our senses are tuned to the parts of the world that do the most to further human survival. So it should come as no surprise that there are wavelengths of light you’ll never see, frequencies of sounds you’ll never hear, and chemicals that won’t trigger the slightest reaction from your nose or tongue. All your senses are constrained by limits like these. When you look, listen, smell, or taste, you’re peering out into the world through the narrow chinks of the cavern you inhabit.

The more you explore your senses, the more you’ll realize that they don’t just pick up on external reality. Instead, they collaborate with your brain to convert a portion of reality into something that’s meaningful to you. That’s how slightly different wavelengths ...