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Chaos, complexity and quantum indeterminacy cannot save free will
Robert Sapolsky's arguments against free will are based, fundamentally, on the biological nature of the mind –which is what produces behavior–, on its ontogenetic and evolutionary past. And also, on the influence of cultural and environmental factors in general on the biological phenomena underlying decision-making.
Proponents of free will who accept the validity of these arguments invoke, to counteract their effect on the ability to make free decisions, other phenomena that are also dealt with by science. To briefly summarize, the phenomena invoked are chaos, complexity and emergence, and quantum indeterminacy. Sapolsky breaks down the arguments based on these phenomena to conclude that none of them serves to deny determinism in nature and, therefore, in the decisions we humans make. Let's look at it in some detail.
Simplifying a lot, a chaotic system is characterized by a behavior that is very sensitive to the initial conditions, so that a minimum variation in these conditions gives rise to a very large difference in its future state. For that reason, chaotic systems are unpredictable.
Believers in free will who invoke chaos theory in its defense understand that on certain occasions of special significance, the mind's decision is unpredictable. And, since it cannot be predicted, it is assigned an indeterminate character. From this point of view, the (assumed) indeterminism of chaos means that, although it does not help to prove that there is free will, it allows us to demonstrate that it cannot be proved that there is none.
I have written "assumed" in brackets because determinism and predictability are very different matters. That the chaotic is unpredictable does not mean that it is not deterministic. Everything that happens in a chaotic system has its origin in what has happened before in that system, regardless of whether it can be predicted or not. In short, chaos is not on the side of free will.
Living systems are complex. From molecules, through cells, tissues, organs and organisms, they are complex systems; the human brain is also complex, of course, perhaps the most complex object in the Universe. These systems are the result of the conjunction of simpler parts that interact with each other. The interesting thing is that they have characteristics and display behaviors that are not only different from those of the elements that integrate them, they are new, but also unpredictable from those. A neuronal circuit presents a different behavior from that of the individual neurons that constitute it, and an encephalic area has different characteristics from that of the nerve pathways that are part of it.
Some of those who defend the existence of free will argue that the emergence, the appearance of new behaviors and properties in the brain, as a complex system, can explain the existence of free acts.
The philosopher Christian List in his Why Free Will is Real (2019) argues, on emergentist grounds, that free will is real, that it defies scientific orthodoxy and defends it in the same naturalistic terms that are normally used against it. He admits, therefore, that free will and its prerequisites (intentional agency, alternative possibilities of choice, and causal control over our actions) cannot be found among the fundamental physical features of the natural world. But, he argues, that is not where we should look. According to him, it is a "higher level" phenomenon that is at the level of psychology. It is like other phenomena that arise from physical processes but are autonomous from them and are not best understood in fundamental physical terms, as is the case with ecosystems or the economy. When we discover it in its proper context, recognizing that free will is real is not only scientifically respectable; it is indispensable for explaining our world.
Christian List, therefore, autonomizes the system "mind" - the generator of behavior - from the elements that make it up to the point that he completely disregards the conditioning factors that act on its constituent parts.
Sapolsky counters by asserting that, even if a system has emergent properties, that does not mean that such a system can choose to do whatever it wants; for it is still composed of and constrained by its constituent parts, with all their limits and weaknesses. And that emergent systems cannot cause "the bricks with which they were built to cease to be bricks".
The inability to know, simultaneously, the location and momentum of a particle; for an object to simultaneously possess two or more values of an observable quantity; for particles to be in multiple places at once; or the impossibility of knowing which slit an electron will pass through once a wave has collapsed, all introduce a fundamental indeterminism into the universe.
This indeterminism is invoked by some proponents of free will to explain its existence.
However, no one has been able to explain how such indeterminism, which occurs at the subatomic level of matter, can have effects at higher levels of organization, such as a neuron or a nervous circuit. Most specialists conclude that the most likely scenario is that any given quantum event is lost in the noise of a staggering number of other quantum events occurring at different times and in different directions.
The law of large numbers, combined with the large number of quantum events occurring in any macro-level object, assures us that the effects of random fluctuations at the quantum level are completely predictable at the macro level, in much the same way that casino winnings are. Predictable, even if based on millions of "purely chance" events.
The randomness of quantum phenomena does not help to solve the problem of free will either. That indeterminism introduces randomness into the basic structure of the Universe, not at higher levels of organization, so the hypothesis that some of our acts are freely decided is not the same as the hypothesis that some of our acts occur freely at random.... How does one go from chance to rationality? Chance is, according to Sapolsky, as implacable as necessity.
In short, there is no evidence that quantum phenomena can underlie possible non-deterministic behavior. In the author's words, quantum strangeness is not so strange, and quantum effects fade amidst the warm, wet noise of the brain as one moves to higher levels of organization.
But there is more, even if quantum indeterminacy were to reach down to the level at which behavior is generated, all it would produce is randomness. “Is the free will for which we would deserve punishment or reward really based on randomness?” asks Sapolky.
Chaos, complexity and quantum indeterminacy cannot save free will
The conclusion that the author reaches, after analyzing the way in which the mechanisms presented here could be at the basis of conscious and free behavior, is that there is no real possibility of it. Neither chaos, nor complexity, nor quantum indeterminacy come to the rescue of free will. None of them amends the deterministic nature of the macro levels of reality, including the very levels of a human brain.
In the third and final installment of this series, I will present the consequences that follow from the non-existence of free will and where are the most powerful reasons why it is not admitted by a great majority of philosophers and not a few neuroscientists.
Note: The third and final part of this review will be published next week. You can read here the first part.
Title: Determined–Life Without Free Will
Author: Robert M. Sapolsky
Ed. by Vintage, 2023.