Did Evolution Give Us Free Will?

A neuroscientist takes on determinism.

- RONALD BAILEY

WHAT IS FREE will? Can a being whose brain is made up of physical stuff actually make undetermined choices?

In Free Agents: How Evolution Gave Us Free Will, the Trinity College Dublin neuroscientist Kevin J. Mitchell argues that evolution has shaped living creatures such that we can push back when the physical world impinges upon us. The motions of nonliving things—air, rocks, planets, stars—are entirely governed by physical forces; they move where they are pushed. Our ability to push back, Mitchell argues, allows increasingly complex creatures to function as agents that can make real choices, not “choices” that are predetermined by the flux of atoms.

How can that be? After all, just like air and rocks, bacteria and sharks and aardvarks and people are made of physical stuff. Determinism holds that, per the causal laws of nature, the unfolding of the universe is inexorable and unbranching, such that it can have only one past and one future. Human beings do not escape the laws of nature, so any and all of our “choices” have been predetermined from the beginning of the universe.

This view poses a moral problem: How can people be held accountable for their actions if they had no choice but to behave the way they did?

Some determinist philosophers, known as compatibilists, hold that causal determinism is compatible with free will. Daniel Dennett, for example, argues that you are exercising your free will if, in the absence of external coercion, you are acting in accordance with your desires. As the 19th century philosopher Arthur Schopenhauer put it, “Man can do what he wills but he cannot will what he wills.”