Your brain is built of cells called neurons and glia — hundreds of billions of them. Each one of these cells is as complicated as a city. And each one contains the entire human genome and traffics billions of molecules in intricate economies. Each cell sends electrical pulses to other cells, up to hundreds of times per second. If you represented each of these trillions and trillions of pulses in your brain by a single photon of light, the combined output would be blinding.
The cells are connected to one another in a network of such staggering complexity that it bankrupts human language and necessitates new strains of mathematics. A typical neuron makes about ten thousand connections to neighboring neurons. Given the billions of neurons, this means there are as many connections in a single cubic centimeter of brain tissue as there are stars in the Milky Way galaxy.
The three-pound organ in your skull — with its pink consistency of Jell-o — is an alien kind of computational material. It is composed of miniaturized, self-configuring parts, and it vastly outstrips anything we've dreamt of building. So if you ever feel lazy or dull, take heart: you're the busiest, brightest thing on the planet.
However, you're an odd kind of newspaper reader, reading the headline and taking credit for the idea as though you thought of it first. You gleefully say, "I just thought of something!", when in fact your brain performed an enormous amount of work before your moment of genius struck. When an idea is served up from behind the scenes, your neural circuitry has been working on it for hours or days or years, consolidating information and trying out new combinations. But you take credit without further wonderment at the vast, hidden machinery behind the scenes.
And consider the British poet Samuel Taylor Coleridge. He began using opium in 1796, originally for relief from the pain of tooth-aches and facial neuralgia — but soon he was irreversibly hooked, swigging as much as two quarts of laudanum each week. His poem "Kubla Khan," with its exotic and dreamy imagery, was written on an opium high that he described as "a kind of a reverie." For him, the opium became a way to tap into his subconscious neural circuits. We credit the beautiful words of "Kubla Khan" to Coleridge because they came from his brain and no else's, right? But he couldn't get hold of those words while sober, so who exactly does the credit for the poem belong to? As Carl Jung put it, "In each of us there is another whom we do not know." As Pink Floyd put it, "There's someone in my head, but it's not me."