I’ll mention what I’ll call the “radio theory” of brains. Imagine that you are a Kalahari Bushman and that you stumble upon a transistor radio in the sand. You might pick it up, twiddle the knobs, and suddenly, to your surprise, hear voices streaming out of this strange little box. If you’re curious and scientifically minded, you might try to understand what is going on. You might pry off the back cover to discover a little nest of wires. Now let’s say you begin a careful, scientific study of what causes the voices. You notice that each time you pull out the green wire, the voices stop. When you put the wire back on its contact, the voices begin again. The same goes for the red wire. Yanking out the black wire causes the voices to get garbled, and removing the yellow wire reduces the volume to a whisper. You step carefully through all the combinations, and you come to a clear conclusion: the voices depend entirely on the integrity of the circuitry. Change the circuitry and you damage the voices.

Proud of your new discoveries, you devote your life to developing a science of the way in which certain configurations of wires create the existence of magical voices. At some point, a young person asks you how some simple loops of electrical signals can engender music and conversations, and you admit that you don’t know—but you insist that your science is about to crack that problem at any moment.

Your conclusions are limited by the fact that you know absolutely nothing about radio waves and, more generally, electromagnetic radiation. The fact that there are structures in distant cities called radio towers—which send signals by perturbing invisible waves that travel at the speed of light—is so foreign to you that you could not even dream it up. You can’t taste radio waves, you can’t see them, you can’t smell them, and you don’t yet have any pressing reason to be creative enough to fantasize about them. And if you did dream of invisible radio waves that carry voices, who could you convince of your hypothesis? You have no technology to demonstrate the existence of the waves, and everyone justifiably points out that the onus is on you to convince them.

So you would become a radio materialist. You would conclude that somehow the right configuration of wires engenders classical music and intelligent conversation. You would not realize that you’re missing an enormous piece of the puzzle.

I’m not asserting that the brain is like a radio—that is, that we’re receptacles picking up signals from elsewhere, and that our neural circuitry needs to be in place to do so—but I am pointing out that it could be true. There is nothing in our current science that rules this out. Knowing as little as we do at this point in history, we must retain concepts like this in the large filing cabinet of ideas that we cannot yet rule in favor of or against. So even though few working scientists will design experiments around eccentric hypotheses, ideas always need to be proposed and nurtured as possibilities until evidence weighs in one way or another.

--David Eagleman, Incognito: The Secret Lives of the Brain, Random House, pp. 221-222