Einstein, Free Will, and Quantum Mechanics
Although Einstein abandoned his faith in a personal God at a young age, Isaacson notes that he had little patience or respect for simple materialist atheism. “The fanatical atheists,” Einstein wrote, “are like slaves who are still feeling the weight of their chains which they have thrown off after hard struggle. They are creatures who—in their grudge against traditional religion as the ‘opium of the masses’—cannot hear the music of the spheres.” The cosmos was symphonic for Einstein, and his God was revealed in the harmony of its laws. Simultaneously a determinist and a theist, Einstein saw proof of a divine Author in the intricate, beautiful ways in which everything seemed to be determined.
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Since Einstein’s death, quantum theory’s verification has cast serious doubts on determinism and helped recover human free will in science. As Stephen Barr writes in “Faith and Quantum Theory” (subscription required, First Things, March), Einstein “detested the idea that a fundamental theory should yield only probabilities. ‘God does not play dice!’ he insisted. In Einstein’s view, the need for probabilities simply showed that the theory was incomplete.”
Well, he was wrong. And in being wrong about quantum theory, Einstein was also wrong about the impossibility of free will. The steps in logic taken to get from quantum probabilities to the freedom of the human mind are surprising, yet convincing. Barr concludes: “As long as only physical structures and mechanisms are involved, however complex, their behavior is described by equations that yield only probabilities—and once a mind is involved that can make a rational judgment of fact, and thus come to knowledge, there is certainty. Therefore, such a mind cannot be just a physical structure or mechanism completely describable by the equations of physics.” This leaves room for the mind to be free.
Although unclear, I think that what Rose (and Barr) are trying to argue is that some variant of the Heisenberg uncertainty principle is at play in human behavior. As originally presented, this principle states that we cannot know both the position and momentum of a tiny moving particle such as an electron or photon. Our knowledge of position will affect momentum and vice versa. The principle has more broadly been stated as making a more revolutionary but solidly evidenced claim (known as the Copenhagen interpretation) that there is no deterministic universe to begin with--all matter is nothing more than a probability wave function. And critically, our knowledge of the state of one property of a particle will cause the wave function to collapse to one state or another of another property of that particle--but that state is only determined when we make the measurement.
What is the application to free will? It appears that Rose and Barr are viewing the human mind as akin to a physicist measuring the state of a particle. Much as the physicist can affect the state of a particle (causing wave function collapse) by measuring another state of that particle, the mind also can cause a change in the state of the human brain. this means that our decisions are not merely affected by the biochemistry of the brain--our mind can affect the outcome of that biochemistry.
I think this takes quantum mechanics too far. Quantum mechanics works remarkably well at the level of photons and electrons, but it becomes unimportant at the level of human beings--from our point of view, we live in deterministic universe. I am sitting on a hard chair and am typing on a hard keyboard. I see real objects that act like real objects--I don't see a probabilistic wave function. I therefore doubt that quantum mechanics offers an explanation for free will. Our mind seems to operate in this macro deterministic world, and not in the probabilistic world of quantum mechanics.
This is not to say that quantum mechanics does not have some importance to our faith. If the Copenhagen interpretation is correct, nothing is impossible. Events are highly improbable, but nothing is impossible. What does that mean? Well, scientifically, it is possible for water to turn into wine, for loaves of bread to appear out of apparent nothingness, and for illness to be miraculously cured. In other words, the post-Enlightenment view that the miracles described in the Bible could not have occurred is wrong; while these events are certainly highly unlikely, the probability is greater than zero.