Astronomy naturally inspires cosmic thinking, but astronomers rarely tackle philosophical issues directly. Theoretical astrophysicist Robert O. Doyle, Ph.D. ’68, associate of the department of astronomy, is an exception. For five years, Doyle has worked on a problem he has pondered since college: the ancient conundrum of free will versus determinism. Do humans choose their actions freely, exercising their own power of will, or do external and prior causes (even the will of God) determine our acts?
Since the pre-Socratics, philosophers have debated whether we live in a deterministic universe, in which “every event has a cause, in a chain of causal events with just one possible future,” or an indeterministic one, in which “there are random (chance) events in a world with many possible futures,” as Doyle writes in Free Will: The Scandal in Philosophy (2011). The way out of the bottle, he says, is a “two-stage model” whose origin he traces to William James, M.D. 1869, LL.D. ’03, philosopher, psychologist, and perhaps the most famous of all Harvard’s professors.
Some of the confusion, Doyle believes, stems from how thinkers have framed the question—in an either/or way that allows only a rigidly predetermined universe or a chaotic one totally at the mercy of chance. David Hume, for example, asserted that there is “no medium betwixt chance and an absolute necessity.” But Doyle also finds the term “free will” unclear and even unintelligible, because the condition of “freedom” applies to the agent of action, not the will: “I think the question is not proper, whether the will be free, but whether a man be free,” in John Locke’s concise phrasing. “The element of randomness doesn’t make us random,” Doyle says. “It just gives us possibilities.”
Doyle limns a two-stage model in which chance presents a variety of alternative possibilities to the human actor, who selects one of these options and enacts it. “Free will isn’t one monolithic thing,” he says. “It’s a combination of the free element with selection.” He finds many antecedents in the history of philosophy—beginning with Aristotle, whom he calls the first indeterminist. But he identifies James as the first philosopher to clearly articulate such a model of free will, and (in a 2010 paper published in the journal William James Studies and presented at a conference honoring James; see “William James: Summers and Semesters”) he honors that seminal work by naming such a model—“first chance, then choice”—“Jamesian” free will.
In 1870, James famously declared himself for free will. In a diary entry for April 30, he wrote, “I think that yesterday was a crisis in my life. I finished the first part of Renouvier’s [French philosopher Charles Renouvier, 1815-1903] second Essais and see no reason why his definition of free will—‘the sustaining of a thought because I choose to when I might have other thoughts’—need be the definition of an illusion. At any rate, I will assume for the present—until next year—that it is no illusion. My first act of free will shall be to believe in free will.”
James identified chance as the source of “ambiguous possibilities” and “alternative futures.” “Chance is not the direct cause of actions,” writes Doyle. “James makes it clear that it is his choice that ‘grants consent’ to one of them [alternatives].” In an 1884 lecture, “The Dilemma of Determinism,” James challenged some Harvard divinity students to ponder his choice of a route home after the talk. “What is meant by saying that my choice of which way to walk home after the lecture is ambiguous and a matter of chance?....It means that both Divinity Avenue and Oxford Street are called but only one, and that one either one, shall be chosen. The notion of alternative possibility…is, after all, only a roundabout name for chance.”
Chance and randomness, however, are concepts that make many academics uncomfortable. “Philosophers and mathematicians hate probability,” says Doyle. “All the great mathematicians—Laplace and Gauss, for example—did not believe chance was real. ‘Laws of chance,’ as they call probability—are only able to describe events, but there is no real chance, because God clearly knows what’s going to happen. Most of these thinkers—centuries ago—were very religious. And even today mathematicians like to think someday we’ll discover the ‘laws of chance’—which makes randomness sound regular and lawful.”
In the life sciences, where results depend not only on abstract cerebral processes but data that stream in from nature, chance gets more respect. James was highly conversant with Charles Darwin’s work, in which evolutionary theories embraced random mutations of genes. More recently, German neurobiologist and geneticist Martin Heisenberg (son of physicist Werner Heisenberg, winner of the Nobel Prize for his work on the uncertainty principle) published a 2009 Nature article on free will (with a letter from Doyle), describing how the bacterium Escherichia coli moves in two ways: either tumbling randomly or heading purposefully forward. “This ‘random walk’ [of tumbling] can be modulated by sensory receptors, enabling the bacterium to find food and the right temperature,” Heisenberg writes. Thus, a two-stage process combining chance with choice might even apply at the unicellular level of life.
Quantum physics, by putting physical science on a probabilistic footing, erased any ambitions to remove randomness from its equations. British astrophysicist Arthur Stanley Eddington (1882-1944) even declared, “Now that physics is no longer deterministic—because of quantum physics—the door is open to free will,” reports Doyle. “And the philosophers said to him, ‘What? You think a free electron makes us free?’” Eddington eventually backed off his position, but subsequent decades of work have only strengthened the claims of the quantum model. “Quantum physics makes predictions to 14 decimal places,” Doyle says. “It’s the most accurate of all mathematical physical theories.” Randomness and even free will, it appears, are fully compatible with some highly precise determinations.
