THE PROBLEM OF FREE WILL AND DETERMINISM: ARE WE CLOSE TO SOLVING IT?

The progressive worldview, in the “big picture” sense I understand it, involves equal parts philosophy, science, and political theory. In my four posts on The Progressive Worldview Blog thus far, I’ve mainly talked politics and science, so for this fifth post, let’s go full-on philosophy—although weaving in a bit of science here and there.

One of the thorniest problems philosophers and theologians have grappled with over the ages is that of free will and determinism. Are human beings free to determine their thoughts and actions, as would seem to be necessary for any rich notion of morality? Or are we fully determined in our decision-making, as other considerations in a person’s philosophy, theology, or science might demand? For nearly two thousand years of western intellectual history, this has not merely been an interesting topic of philosophical speculation but a true problem, as there seemed to be good reasons for grabbing both horns of the dilemma--for insisting both that we are free and that we are determined in some sense.

That said, with modern science having made incredible advances over the past couple centuries in fields including quantum physics and neurophysiology, some philosophers and scientists have begun to speculate that we may be closer than ever to finally solving this nagging problem. In this post, I’ll offer my own take on this debate, and I’ll give away the punch line up front: From what I can tell, we are no closer to solving the problem of free will and determinism than our predecessors were. But even as someone who has a deep interest in moral philosophy, that does not worry me terribly, because I don’t believe the remaining mysteries surrounding free will and determinism are still the problem they once were.

In fact, free will and determinism was not always a problem in the western tradition. Plato and Aristotle barely had a conception of the will, and when the Stoics began making the first references to a distinct faculty of will, they did not see any incompatibility between the will being free and the larger world being deterministic. On the contrary, they believed that because the world is a strictly deterministic order that we cannot alter through any effort of will, the key to happiness lies in freely accepting the necessity of things, or accommodating the will to world.

The Roman poet Lucretius appears to have been the first major figure in the western tradition to have sensed there might be a problem lurking with respect to free will and determinism, as least judging by the solution he proposed. Writing in poetic form in the first century BCE, Lucretius offered an epic account—de Summa Rerum—of the atomistic metaphysics first advanced by the Greek philosopher Democritus. The Democritean world consists of nothing but atoms racing through the void, sometimes colliding with other atoms and thereby determining one another’s motions in purely mechanistic fashion. The human body is likewise composed of atoms, with a particularly small, smooth variety of atom forming its soul. Apparently worried that this view of nature would lock human beings into a strict, mechanical determinism, Lucretius made one addition to the Democritean system: he proposed that, as atoms race through the void in their usual straight lines, occasionally--and completely at random—one will swerve. With our soul-atoms being among those that occasionally swerve, human action is freed from an absolute mechanical necessity. Whether this solution to the problem of free will and determinism supports a rich notion of human freedom is open to debate: Is occasionally acting randomly any better than being fully determined? Nevertheless, Lucretius’s attempted solution to the problem of free will and determinism at least put the problem squarely on the table.  

And the problem soon became a very big problem, a potential scandal that threatened to topple a much larger metaphysical edifice. This happened as Christianity grew from being a small offshoot of Judaism to becoming the official religion of the Roman Empire, thereby setting the stage for its dominance of western culture for the next 1,500 years. With this young religion having inherited the Hebrew doctrine of monotheism, when its first theologians began applying such Greek philosophical concepts as perfection and absoluteness to their conception of God, they quickly bumped up against their first major problem: the problem of evil. Assuming God is perfect and absolute in every regard—omnipotent, omniscient, and omnibenevolent—why should there be evil in the world? Was God not powerful enough to prevent its rise? Not smart enough? Not good enough? A variety of responses to this trilemma have been suggested over the millennia, but already by the fourth century CE, Augustine of Hippo had proposed the answer that would become orthodoxy. It was an answer that simultaneously addressed the problem of free will and determinism.

God could easily determine our every move if he wanted to, Augustine observes in On Free Choice of the Will. If he did, however, we could not meaningfully be good, since we would be nothing more than marionettes dancing on strings. God therefore granted human beings free will so that we might choose to be good, even if this meant we could also make bad choices. Adam, of course, made a very bad choice straight out of the gate, thereby corrupting the world and leading us to commit further sins of our own, thus explaining all the evil we see around us. The presence of so much evil in the world is regrettable, but it not God’s fault. Evil is rather our fault, thereby extricating God from one potential scandal. As Augustine realized, however, another potential scandal with respect to freedom and determinism still lurked.

This second problem Augustine considered was connected less with God’s omnipotence than with his omniscience. Specifically, even if God withheld some of his own power to give us free will, an omniscient God will know the choices we are going to make even before we make them—indeed, even before he has created us. If God nonetheless allows us choose evil when he could have could have redirected our efforts, doesn’t this make God complicit in our sins? The Christian doctrine of heaven and hell only raises the stakes of this question, since it implies our bad choices will not only bring us discomfort in this life but an eternity of torture. Is it really fair that we should be sentenced to such an abysmal fate if it was already determined how we would behave before we were born? Isn’t God the true author our sins, since he went ahead and created us, even foreseeing that we would fall and be damned?

With God’s unique status as an absolute Being having gotten him into this potential scandal, Augustine uses God’s absoluteness to get him out. He observes that, in everyday life, I may watch another person doing something bad, say, stealing a loaf of bread from a baker’s stall. The fact that I can see what happens does not make me responsible for this theft; it is it thief who is responsible for his crime. Perhaps if I knew in advance this theft was going to occur and I did nothing to stop it, I might bear some responsibility for the ultimately result. Merely watching the crime unfold in real time, however, does nothing to implicate me. Yet, Augustine notes, this is essentially the position God occupies. Given his absolute, unbounded nature, God does not exist in time. Rather, God exists beyond time, first creating the temporal order when he creates the rest of the world. And even after God has created the world, he remains outside its temporal flow, with past, present, and future all being equally present before him in an “eternal now.” When the thief steals a loaf of bread, therefore, God does not have foreknowledge of this event, which would imply the thief was predetermined in his actions. Standing outside the flow of time, God does not experience before and after; he merely gazes upon the flow of events like a human observer watching in real time, no more responsible for the thief’s actions than a human witness would be. And since God is not responsible for this crime, there is nothing untoward in him sentencing the thief to an eternity of hell. Once again, the potential scandal of God doing something evil had been averted, so the larger edifice of Christian metaphysics could stand.

When the Scientific Revolution erupted in the early seventeenth century, it began challenging Christian metaphysics in many ways. So doing, however, it bumped up against another version of the problem of free will and determinism, one just as worrisome as what Christianity had faced. The foundational tenet of modern science is that all of nature is governed by certain unchanging, inflexible, universal laws of nature. Isaac Newton captured this view of nature in magisterial fashion toward the end of the seventeenth century with his publication of Principia Mathematica, which treats the entire universe as a single, unified, interconnected system of causal laws. Even earlier in the century, however, philosophers had begun to realize that the emerging scientific view of nature could pose a threat to morality, for the same reason Lucretius had been worried about Democritean atomism. In a mechanically operating universe governed by a set of unchanging, universal laws, is moral action still possible? Was there a way to “save” morality by developing a coherent doctrine of moral action, even while preserving the mechanistic view of nature that was yielding such spectacular results in the natural sciences?

Rene Descartes, commonly regarded as the father of modern philosophy, did not spend a great deal of time mulling the problem of free will and determinism, but that is probably only because he believed he had already solved it. Noting that the essence of material bodies is their geometric shape—their extension in space—Descartes argued that this extended nature is what allows bodies to bump into one another, thereby generating a mechanistic material order. As he reflected on his own thoughts, however, and on himself as a thinking thing, Descartes determined that the human mind is unextended, such that it cannot bump into extended bodies. With the mind thus standing outside the causal order of material nature, Descartes concluded that the mind is perfectly free, untouched by any of the problems of mechanical determinism.

Of course, Descartes’s mind-body dualism gave rise to any number of other problems, the most obvious being that of mind-body interaction. Experience tells us the mind is capable of directing the body’s actions, even as the body constantly transmits sensations back to the mind. Yet, how are either of these interactions possible if unextended minds cannot bump into extended bodies? Descartes suggested this interaction might take place in the pituitary gland, a globular organ hanging right in the mind of the brain, thus potentially rendering it sensitive enough to pick up the subtle buzzing of the mind’s thoughts. But this suggestion impressed no one, since Descartes’s own arguments for dualism had clearly ruled out even such a delicate form of interaction between two radically different substances.

Across the English Channel, Descartes’s contemporary, Thomas Hobbes, was making an entirely different attempt to save morality from the possible pitfalls of determinism. Impressed with the work Galileo was doing in physics, Hobbes reasoned that if all of nature is governed by a set of relatively simple, universal laws—on the order of Galileo’s law of falling bodies—and if human beings are part of nature, then human beings must be likewise be determined in all their actions by some relatively simple law or laws. Looking around him, not just at other people but at the rest of the animal kingdom, Hobbes concluded the only reasonable candidate for a law of human nature is the law of self-interest. Just like any other beast, that is, we inevitably strive to act in our own perceived self-interest. Admittedly, starting out by maintaining that we are not only mechanically determined in all our actions, but we are determined to behave in egoistic fashion, does not sound like a promising foundation upon which to build a moral theory. But Hobbes went ahead and built one anyway, developing what came to be known as contract theory.

Prior to the rise of civic society, Hobbes argued, people must have lived in a “state of nature” that lacked any of the laws or norms that have since come to define civilized, moral behavior. Inveterately self-interested, these pre-civic people would have naturally fallen into a “war of all against all” as they scrambled for scarce resources, with constant fear and violence rendering life in the state of nature “solitary, poor, nasty, brutish, and short.” Again, a dismal starting point, yet the very miserableness of the state of nature, Hobbes reasoned, would have eventually driven its inhabitants to realize it would be in their own best interest to accept certain limits on their actions, provided others did the same. And thus our ancestors forged a social contract, collectively submitting themselves to both the rule of law and the rule of a sovereign appointed to enforce this law. As it turns out, then, the fact that human beings are determined to act in their own self-interest does not spell the death of morality. This implacable self-interest is what rather led our ancestors to institute a moral order in the first place.

Contract theory ended up being tremendously significant for the development of the modern world, particularly once John Locke had softened the rough edges of Hobbes’s account of human nature, thus helping to inspire the American Revolution and the democratic system of government it ultimately yielded. Other British thinkers, meanwhile, adopted Hobbes’s general approach of accepting self-interest as the basic principle of human action, but showing that socially responsible action is nonetheless possible. In The Wealth of Nations, for instance, Adam Smith showed how, in the context of free trade, the “invisible hand” of the market will take the self-interested behavior of distinct economic actors and convert it into mutually beneficial results. Meanwhile, various moral sentiment theorists, to include Smith, himself, as well as his teacher, Frances Hutcheson, and his friend and colleague, David Hume, took a slightly different approach to reconciling mechanically-driven egoism with traditional morality. The sentiment theorists argued, in short, that human beings are endowed with certain moral sentiments, such as sympathy, that make us feel good when we help others and feel bad when we observe suffering. And thus we have a self-interested reason to engage in what are traditionally considered moral or even altruistic actions: it just feels better than constantly taking advantage of others.

If the empirically-minded philosophers of the British Isles were therefore content to develop their moral theories in the context of a metaphysics that was both materialistic and deterministic, more rationally-leaning philosophers on the European continent continued to worry that subjecting human beings to the deterministic laws of a Newtonian universe would render any true moral action impossible. Foremost among these was Immanual Kant, who sought to put the problem of free will and determinism to rest once and for all in the Critique of Pure Reason. Kant’s entire philosophy is notoriously challenging, so trying to condense this particular argument into a few paragraphs will not be easy, but I’ll give it my best shot.

Kant essentially went back to Descartes and noted that the sharp metaphysical line Descartes had drawn between the mind and body had essentially forced his successors to choose whether they wanted to prioritize the mind and its possibility of freedom (as the continental rationalists generally did) or the body and its adherence to the Newtonian system of universal laws (as the British empiricists did). Yet, this metaphysical characterization of the mind and body had been misguided from the start, Kant argued. Descartes had insisted that bodies are defined, in their metaphysical essence, by their extension. But Kant replied that we have no idea what bodies are in their metaphysical essence. That is because we can never steps outside our thoughts and perceptions to see what bodies really are in themselves. All we can know of bodies is what we perceive of them, or how they appear to us. In Kant’s formal terminology, we have no epistemic access to things in themselves, but only to appearances. It is certainly true that, insofar as bodies appear to us, they are governed by Newton’s laws; or in any case, we apply these hypothetical laws of nature to our appearances in order to make sense of them. But whether things in themselves are governed by Newton’s laws or any analogue of them, we simply have no idea.

These observations might appear to suggest that all the mind can truly know is itself. But Kant does not even give us this, for we run into much the same wall when we turn our thoughts inward. I may try to catch a glimpse of the “I” who is thinking—the thinking thing that Descartes declared to be a metaphysically real, unextended substance. In reality, however, all I can observe are the thoughts streaming by. I can form the idea of a unified thinker conceiving all these thoughts, but this just gives me the mind insofar as it appears to me. What the “mind-in-itself” is, in its metaphysical nature, we have no idea. This leaves us knowing much less about either bodies or minds than philosophers had long thought. Yet, recognizing this fact is actually a blessing, Kant argued, since it essentially dissolves the problem of free will and determinism, along with Descartes’s mind-body problem.

Starting with the latter problem, given that we do not know bodies-in-themselves are, nor do we know what minds-in-themselves are, we have no reason to suspect they are metaphysically incapable of interacting with one another. And since minds and bodies do appear to interact all the time, it would seem they must be able to. Mind-body problem solved. By the same token, since we do not know what minds-in-themselves are, nor do we even know whether bodies-in-themselves are governed by some analogue of Newton’s laws—the universal laws of nature, again, are something that apply only to appearances—there is no contradiction in supposing both that the laws of nature rule the material realm and that the mind-in-itself is free of their mechanical determinism. For the sake of morality, Kant concludes, we may as well behave as if we are free, striving to act in a fashion governed more by reason and the dictates of morality than by self-interest. Should we succeed in this regard—behaving in the material realm in a fashion only free beings could be expected to behave—we will have succeeded in demonstrating that free will can perfectly well coexist with a material realm governed by the inflexible, universal laws of nature.

As someone with formal training in philosophy who has a particular affinity for Kant, I am reasonably satisfied with the resolution he proposed to the problem of free will and determinism. I am quite aware, however, that Kant’s argument is hardly user-friendly, and thus it may not be terribly compelling to anyone who has not spent years steeping themselves in the Kantian system. So here is where turning to more recent developments in the natural sciences may be more helpful.

As most readers will know, the Newtonian model of the universe collapsed over the first few decades of the twentieth century, yielding to the twin challenges posed by relativity theory and quantum mechanics. Granted, Newton’s equations continue to work under all but the most extreme conditions, as when a body is travelling close to the speed of light. Relevant to our discussion here, however, the Newtonian presumption that fell apart was the claim that every that event in the universe is fully determined by some prior set of causes. It was quantum mechanics, in particular, that quashed the thoroughgoing determinism of the Newtonian universe.

To cite just one simple example, the half-life of uranium-238 is 4.5 billion years. This means that if you have one gram of uranium today, in 4.5 billion years exactly half a gram of uranium will have decayed away, leaving you with another half gram. This is deterministic enough in character, yet if you focus on one particular atom of uranium, it is completely random whether this atom will decay at any moment, with each particular atom the original pile having a 50-50 chance of decaying over the span of 4.5 billion years. For decades, many top scientists—including Albert Einstein—were convinced there must be some “hidden variable” determining why one uranium atom decays and another does not; “God does not play dice with the universe,” Einstein lamented. But experimental evidence has convinced almost every physicist working today that there are no hidden variables. Rather, Lucretius was right: atoms really do swerve, after a fashion. Nature, that is, contains an irreducible dash of randomness, or indeterminism, at its core. To be sure, with trillions of atoms in a given lump of matter all behaving in similarly indeterministic fashion, their “swerves” tend to cancel one another out, which is why Newton’s deterministic laws still work very well at the macroscopic level. But the development of chaos theory later in the twentieth century showed that, occasionally, quantum indeterminism can leak through to the macroscopic level.