Is the fact you are reading this story a decision you arrived at it by your own free choice, or was your interest programmed into the universe from the moment of the big bang? What makes free will such a fun topic is not only that it dives deep into physics, neuroscience, and philosophy, but also that we all feel we have a direct stake in the answers.
Part of my own interest is that I've never been able to see why people get worked up about a supposed conflict between free will and determinism. To my mind, there is no conflict. Human consciousness and therefore the concept of free will are emergent properties, so whether microscopic physics is deterministic or not is irrelevant. To speak of a conflict is to mix levels of description. In other words, there's no "you" who is steered one way or the other by initial conditions. "You" are a product of those conditions.
I'll grant that all this depends on what precisely we mean by “free will.” To me, it is the fact that you make choices. To others, though, free will involves some inherent unpredictability. In that case, it might well have something to do with the deep laws of nature. Within quantum mechanics, there are four basic arguments for such a connection:
1. Quantum mechanics is indeterministic, in that the outcomes of measurements are chosen at random from the slate of possibilities. So, if quantum effects help to shape our conscious choices, they sever the connection between us and the initial conditions of the universe.
2. When we conduct experiments on quantum particles, we exercise our free will—for example, we make choices about what precisely to ask of the particles. Or at least we think we exercise our free will. How those particles respond can depend on whether we really do.
3. If you could predict someone’s decisions consistently, you could conclude that he or she lacks free will. To do that, you’d need to take a full brain scan and simulate his or her thought processes. Yet quantum physics forbids the reliable, nondestructive copying of particles, let alone whole brains. If you could never observe the loss of free will, then you should doubt whether it is ever really lost.
4. Quantum physics is time-symmetric, so we are as justified in saying that our choices set the cosmic initial conditions as the other way round.
Here, I'll examine each of these contentions. This is an evolving document. Over time, I'll gradually flesh out the points and add interesting new contributions to the debate. Later this year, Scientific American plans to publish a full-blown magazine feature on these issues.