#11: Determinism and Free Will

Some time ago, I decided to take out the trash. On the way to the trash can, I thought, "I should clean out the kitty litter." Started to clean the litterbox, and thought, "No, actually, I should completely change the litter." Started changing the litter, then realized that the cat had dragged some of it out on the floor. "Ah, I should get out the vacuum," thought I.

Next thing you know, I'm totally cleaning the apartment, one end to the other.

On my way out to the dumpster, I started thinking about hourglasses. And that's really what this post is about.

If you have ever watched the sand falling in an hourglass, you know how it goes. The sand in the bottom of the hourglass builds up and up and up, then collapses into a lower, wider pile; then as more sand streams down, it builds up and up and up again until it collapses again.

I don't think any reasonable person would say that a pile of sand has consciousness or free will. It is a deterministic system; its behavior is not random at all, but is strictly determined by the immutable actions of physical law.

Yet in spite of that, it is not predictable. We can not model the behavior of the sand streaming through the hourglass and predict exactly when each collapse will happen.

This illustrates a very interesting point; even the behavior of a simple system governed by only a few simple rules can be, at least to some extent, unpredictable. We can tell what the sand won't do--it won't suddenly start falling up, or invade France--but we can't predict past a certain limit of resolution what it will do, in spite of the fact that everything it does is deterministic.

The cascading sequence of events that started with "I should take out the trash" and ended with cleaning the apartment felt like a sudden, unexpected collapse of my own internal motivational pile of sand. And that led, as I carried bags of trash out to the dumpster, to thoughts of unpredictable deterministic systems, and human behavior.

The sand pouring through the hourglass is an example of a Lorenz system. Such a system is a chaotic system that's completely deterministic, yet exhibits very complex behavior that is exquisitely sensitive to initial conditions. If you take just one of the grains of sand out of the pile forming in the bottom of the hourglass, flip it upside down, and put it back where it was, the sand will now have a different pattern of collapses. There's absolutely no randomness to it, yet we can't predict it because predicting it requires modeling every single action of every single individual grain, and if you change just one grain of sand just the tiniest bit, the entire system changes.

Now, the human brain is an extraordinarily complex system, much more complex both structurally and organizationally than a pile of sand, and subject to more complex laws. It's also reflexive; a brain can store information, and its future behavior can be influenced not only by its state and the state of the environment it's in, but also by the stored memories of past behavior.

So it's no surprise that human behavior is complex and often unpredictable. But is it deterministic? Do we actually have free will, or is our behavior entirely determined by the operation of immutable natural law, with neither randomness nor deviance from a single path dictated by that immutable natural law.

We really like to believe that we have free will, and our behavior i subject to personal choice. But is it?

In the past, some Protestant denominations believed in pre-ordination, the notion that our lives and our choices were all determined in advance by an omniscient and omnipotent god, who made our decisions for us and then cast us into hell when those decisions were not the right ones. (The Calvinist joy in the notion that some folks were pre-destined to go to hell was somewhat tempered by their belief that some folks were destined to go to heaven, but on the whole they took great delight in the idea of a fiery pit awaiting the bulk of humanity.)

The kind of determinism I'm talking about here is very different. I'm not suggesting that our paths are laid out before us in advance, and certainly not that they are dictated by an outside supernatural agency; rather, what I'm saying is that we may be deterministic state machines. Fearsomely complicated, reflexive deterministic state machines that interact with the outside world and with each other in mind-bogglingly complex ways, and are influenced by the most subtle and tiny of conditions, but deterministic state machines nonetheless. We don't actually make choices of free will; free will appears to emerge from our behavior because it is so complex and in many ways so unpredictable, but that apparent emergent behavior is not actually the truth.

An uncomfortable idea, and one that many people will no doubt find quite difficult to swallow.

We feel like we have free will. We feel like we make choices. And more than that, we feel as if the central core of ourselves, our stream of consciousness, is not dependent on our physical bodies, but comes from somewhere outside ourselves--a feeling which is all the more seductive because it offers us a way to believe in our own immortality and calm the fear of death. And anything which does that is an attractive idea indeed.

But is it true?

Some folks try to develop a way to believe that our behavior is not deterministic without resorting to the external or the supernatural. This belief in non-determinism is a necessary component, in tis view, to belief in free will, because if a person's behavior is always deterministic--if a person in a given situation will always and forever do the same things, make the same choices, following a deterministic and immutable script--then where is the room for free will?

Mathematician Roger Penrose, for example, argues that consciousness is inherently dependent on quantum mechanics, and quantum mechanics is inherently non-deterministic. (I personally believe that his arguments amount to little more than half-baked handwaving, and that he has utterly failed to make a convincing, or even a plausible, argument in favor of any mechanism whatsoever linking self-awareness to quantum mechanics. To me, his arguments seem to come down to "I really, really, really, really want to believe that human beings are not deterministic, but I don't believe in souls. See! Look over there! Quantum mechanics! Quantum mechanics! Chewbacca is a Wookie!" But that's neither here nor there.)

Am I saying that the whole of human behavior is absolutely deterministic? No; there's not (yet) enough evidence to support such an absolute claim. I am, however, saying that one argument often used to support the existence of free will--the fact that human being sometimes behave in surprising and unexpected ways that are not predictable--is not a valid argument. A system, even a simple system, can behave in surprising and unpredictable ways and still be entirely deterministic.

Ultimately, it does not really matter whether human behavior is deterministic or the result of free will. In many cases, humans seem to be happier, and certainly human society seems to function better, if we take the notion of free will for granted. In fact, and argument can be made that social systems depend for their effectiveness on the premise that human beings have free will; without that premise, ideas of legal accountability don't make sense. So regardless of whether our behavior is deterministic or not, we need to believe that it is not in order for the legal systems we have made to be effective in influencing our behavior in ways that make our societies operate more smoothly.

But regardless of whether it's important on a personal or a social level, I think the question is very interesting. And I do tend to believe that all the available evidence does point toward our behavior being deterministic, though deterministic in such a chaotic way that functionally, both from our own perspective and from the perspective of the people around us, it is not.