Who we can be begins with our molecular blueprints - a series of alien codes penned in invisibly small strings of acids - well before we have anything to do with it. We are a product of our inaccessible, microscopic history.

Our internal life and external actions are steered by biological coctails to which we have neither immediate access nor direct acquaintance.

There are always wonderful mysteries to confront.

We are made up of an entire parliament of pieces and parts and subsystems. Beyond a collection of local expert systems, we are collections of overlapping, ceaselessly reinvented mechanism, a group of competing factions. The conscious mind fabricates stories to explain the sometimes inexplicable dynamics of the subsystem inside brain. It can be disquieting to consider the extent to which all of our actions are driven by hardwired systems doing what they do best while we overlay stories about choices.

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.

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.

Even while it's true that we are tied to our molecules and proteins and neurons - as strokes and hormones and drugs and microorganisms indisputably tell us - it does not logically follow that humans are best described only as pieces and parts.