Free Agents: How Evolution Gave Us Free Will

In this stimulating treatise, Mitchell (Innate), a genetics professor at Trinity College Dublin, finds evidence for free will in the evolutionary history of humankind. “Agency—the capacity of organisms to act with causal power in the world, for their own reasons—is the defining feature of life itself,” he argues, suggesting that meaningful action emerged when unicellular organisms became capable of collecting information about their environment—the detection of food, for instance, would motivate the organism to seek it out. The development of more complex nervous systems and cognitive processing led to more sophisticated ways of interpreting the world, and eventually human consciousness. Drawing on quantum physics, the author contends that the Heisenberg uncertainty principle—which asserts that “the more precisely you measure the position” of a subatomic particle, the “less precise will be your estimate of its momentum,” making it difficult to predict a system’s future based on its current state—illustrates the deep indeterminacy written into the laws of physics and debunks those who claim that all events and actions are effectively fated to unfold in one way according to those laws. The discussions can get heady, but Mitchell’s lucid explanations keep the philosophical musings down-to-earth (he defines “hard determinism” as the idea that “there are no possibilities—only what has happened and what will happen”). It’s a provocative entry in an ancient debate. (Oct.)