Brains are freaking amazing.

You’re probably wondering why I’m telling you this, as you’ve likely been inundated for the last year with BRAIN initiative news stories exclaiming how the brain is the ultimate frontier of human knowledge and we’re going to throw billions of dollars at it and solve everything and cure schizophrenia and Alzheimer’s! Wooooo!

But maybe you’re still wondering what all the hype is about. Or maybe you’re a neuroscientist like me (hi guys!), so entrenched in studying the function of one specific part of the brain of one specific organism in one particular context that you’ve forgotten what makes the brain so freaking cool.

What is a brain?

A brain is a mass of tangled cells.

A cell is bag of molecules, mostly proteins, fenced off from its surroundings by a fatty membrane.

How is it possible that a 3 pound heap of cells can control everything we do—seeing and hearing, walking and talking, thinking and dreaming?

This mystery is so unfathomable to some people that they don’t believe it’s possible. That there must be something more—a soul or mind separate from the physical entity of the brain. Historically this has been a common view. The idea of a mind distinct from the physical body was perhaps made most famous by Rene Descartes in the 17th century, a view that was later described rather sarcastically by Gilbert Ryle as “the ghost in the machine”. Nonetheless, this idea seems to persist widely today.

Even folks that don’t claim to believe in any non-physical or mystic influences still have trouble wrapping their heads around the idea that our consciousness, our sense of self, stems from nothing more than a pile of cells. Consider an exchange from NPR’s Radiolab, for example, a program dedicated to explaining science (amidst a fair amount of giggling and weird sound effects). On this episode, co-host Robert Krulwich and guest neuroscientist David Eagleman debate whether brain defects that affect behavioral control should be taken into account when judging accused criminals in court.

Krulwich argues that blame for the crime should be ascribed partially to the individual and partially to his brain: “How much do you want to put on the brain, and how much do you want to put on his…”

As Krulwich trails off, Eagleman asks: “What else is there?”

Krulwich responds tentatively: “His behavior…”

Eagleman retorts: “Which comes from where?”

As Krulwich admits all behavior is indeed generated from the brain, Eagleman makes the crucial point: “That’s exactly the problem with our intuitions… that you’ve got this other thing that’s independent of your biology. You ARE your brain.”

The question of whether we have control over our choices—and whether we even have “free will” at all—is a hairy topic for another time. For now, though, the point I’m trying to convey is that everything we do and think, our entire experience of the world, is simply the result of physical processes occuring in our brains. On some level the brain functions like a computer, processing and integrating information in order to produce an appropriate response, albeit a much more powerful, complex, and flexible computer than we’ve ever built.

Still not impressed? Well, I should point out that in this analogy, not only is the brain like a ridiculously powerful, self-aware computer that can change its own programming, but it’s also a computer that BUILDS ITSELF with no outside instructions. Based on information contained within your DNA, each brain cell, called a neuron, somehow knows what kind of neuron to turn into, whether it should give birth to new neurons, where to settle within the brain, and what other neurons to connect to.

Did I mention that there are about 100 billion neurons in your brain, each making on average 1000 connections to other neurons? A matrix of connections between 100 billion neurons would be incredibly difficult for a real computer to keep track of! Yet somehow these billions of little cells know how to come together to form an integrated system, your brain, without anyone even telling them the master plan. And then they know how to work together to perceive the world, make decisions, generate actions. To think and learn and remember. To laugh, cry, and fall in love.

That’s freaking amazing.