What is free will anyway? The concept is deceptively elusive, but most accepted definitions stress a human being's ability to choose one decision over another, often with an emphasis on moral decision-making [source: O'Connor]. Many interpretations of free will even require the presence of a soul or mind that exists independently of the body [source: Nahmias]. But it all comes down to the same question: Are we rational beings who choose our way through life, or are our choices determined by external forces?
Humans have debated this basic philosophical question for thousands of years. For example, the philosophers Democritus and Leucippus saw the universe as wholly governed by natural laws and composed of indivisible atoms. They took the determinist view of a life propelled down a flowing stream of events. Aristotle, however, stressed the individual's responsibility for his or her actions -- the indeterminist view of life as a boat propelling itself through a body of water.
Many of us lean toward this indeterminist view of free will. After all, this philosophical stance places people in a position of power -- as well as responsibility. Indeterminism serves as a prerequisite for the metaphysics of religious faiths as varied as Roman Catholicism and Tibetan Buddhism, both of which involve an afterlife that hinges on choices in the here and now.
Countless others, however, follow in the footsteps of Democritus.
During the Enlightenment of the 17th and 18th centuries, French physicist and mathematician Pierre-Simon Laplace ventured that a sufficiently powerful intellect, with an understanding of Newtonian physics, might track the movements of every particle in the universe and thereby mathematically predict every future event in the cosmos.
Dubbed Laplace's demon, the theoretical entity serves as a sort of mascot for scientific determinism. If the cosmos adheres to certain universal rules, then how could free will possibly exist?
Our growing understanding of neuroscience also raises interesting questions about the role of choice in all our lives. Every day scientists uncover even more about the multiple neurological and biological processes that govern how we think. Brain tumors alter the way we reason. Diet influences our decision-making abilities. The more we map the human genome and study the brain's many subconscious machinations, the more it becomes clear that if free will exists, it's only a minute factor hitching a ride on top of enormous automated machinery -- a principle that neuroscientist David Eagleman calls the principle of sufficient automatism.
Modern science would seem to paint the human experience as a preprogrammed boat gliding down a surging river of events. At the helm, we find a pilot who only thinks he or she commands full control of the vessel -- like a child at the arcade who doesn't realize he's only moving the joystick while a demo plays out on the screen.
Now turn to the next page, where we'll consult Laplace's demon.