If everything, including you and me, is made up of material that blindly obeys the inflexible laws of physics, then everything that happens, including what you and I do, is inevitable, and free will is something of an illusion or a joke.
Or are we just thinking of the question the wrong way?
Make some arbitrary decision (say, to raise your left hand), then imagine turning back the clock and resetting the universe so that every single fact about it was the same as it was before you made that decision. When you restart the clock, would it be possible for you to decide any differently?
If you try to imagine your will, your decision-making apparatus, as something outside of “every single fact about” the universe, as it has been perennially tempting to do, you end up in a morass of speculation about mind and matter, body and spirit, and where they intersect and how. If you avoid this temptation, you just have to argue with the premise of the thought experiment: if it were possible for me to decide differently, at least one single fact about the universe — that decision, embodied however it is in the material world with its material-world consequences — would have to be different in order for me to do so.
That solves the conundrum, sort of, but provokes the worried observation that “that decision, embodied however it is in the material world” is itself an effect of material causes, which does mean (doesn’t it?) that everything is inevitable and predetermined and therefore all of our existential angst is for naught.
Or not. There are a couple of ways out of this fix, too. Gazzaniga toys with a tempting one — that our understanding of quantum physics demonstrates that deterministic cause and effect does not exist at that fundamental level, and chaos theory shows that tiny changes, such as those exhibited at the quantum level, can have dramatic large-scale effects. I get really skeptical whenever a popular science writer starts waving their hands and saying “the uncertainty principle!” “the butterfly effect!” because usually the next thing they say is “therefore, maybe magic is real!” without bothering with the intervening reasoning.
It is true that if the material world is not fundamentally deterministic, but that this causal determinism only appears true when the material world is viewed at a certain granularity, then to say that our minds and our wills are material and behave according to the laws of matter is not to doom them to plodding along in predetermined, inexorable grooves. But this is different from rescuing a naïve free will: if quantum behavior is, to some extent, not in principle predictable, it is also, to that extent, in principle arbitrary. This would seem to move our minds and wills out of the predetermined & inexorable category only to drop us into one at least as frightening: instead of plodding along a predetermined path that was laid out for us in the first moment of creation, we’re randomly sliding down one of an infinite variety of possible paths, but still with no more control over the process than a marble in a chute.
Because the free will we want is not quite so free as that — not a “there’s absolutely no telling what I will do next” sort of free, but an “I’m going to decide what to do next” sort of free. And that sort of free will, Gazzaniga says, we have — as long as we do not try to situate it outside of the physical world or make it somehow immune to the laws of physics. Using our best judgment to make decisions about what to do next is exactly what our brains evolved to accomplish, and they evolved this ability within the real, material world. And that’s OK.
Just as “life” is completely embodied in the material world, and is not some extramaterial essence breathed into it; so “ego” and “will” are as well. This doesn’t make them any less wonderful or worth getting excited about.
But there’s a catch. While we have free will, of this sort anyway, our intuitive idea of how it operates and of “who” operates it is probably wrong. It seems to me as though “I,” a solitary ego who is the sole occupant of my mind or at least the sovereign of that domain, deliberates, makes a decision, and then the rest of me carries it out as ordered. Gazzaniga thinks that scientific experimentation on this hypothesis has pretty much ruled it out as hogwash. More likely, he says, is that a vast, loosely-connected network of mental modules — some exposed to consciousness and some not — make decisions on their own, and then our conscious “decider” comes up with a story line to explain what happened, putting itself in the driver’s seat out of conceit.
We have no access to the inner worlds of other people, and so have to model and predict their behavior as though they were a “black box” — the usual way we do this is to try to model their knowledge, intentions, and reasoning, and make predictions from there. We are so used to doing this that we will even apply this sort of thinking to our predictions of the actions of non-human or even non-living things like robots or marionettes. Our ostensible “decider” — Gazzaniga calls it the “interpreter” — does much the same thing to model the person whose brain it sits inside. In short, the unified decider-ego is not who we are, but is the simplified model that our brain’s interpreter-module makes of us in order to make sense of our behavior and to get insight into what other people must think of us.
(Incidentally, this is how Adam Smith described “conscience” — not as the insight by which we discern good & evil or the nagging voice prompting us to resist temptation, but instead the faculty by which we simulate the perspective of an impartial observer who observes our own headspace and behavior, using the same criteria we naturally use when judging others.)
Because of this, there are times when we say “I decided to do such-and-such for these reasons” and we are just plain wrong. Even the rest of the time, we’re just guessing. It isn’t that we don’t have free will, of a sort, but that it isn’t transparent to us how this free will operates in us.
Which doesn’t mean that it is completely out of our control. We can make decisions that influence the way we will make future decisions: if we educate ourselves, our future decisions will reflect that education; if we practice certain habits, our future decisions will be influenced by those habits; if we stumble upon some creed that agrees with us, we may radically alter our way of being in the world to conform to it. But those decisions themselves are not necessarily under conscious direction: we seem to unconsciously (but note this does not necessarily mean unintelligently or unwisely) become the person we are while at the same time consciously endeavoring to discover the person we have become — and we confuse the one for the other.