What would you do differently if you found out there was no such thing as free will? You should get prepared because the scientific odds seem stacked against free will. It’s ironic to imagine that your belief about free will existing or not could change your behavior. In the end, I don’t think it matters much what you believe—maybe a little, but not nearly as much or for as long as we might think.
See, there are philosophical perspectives and then there’s reality. Philosophers provide us with entryways for thinking about issues that we usually take for granted and guide us to plausible endpoints. Each philosopher takes his or her own path and, depending on their rhetorical skills, each can lead you through a set of intuitions and logical steps until you reach their preferred conclusion. Moments later, another philosopher can lead you to an equally compelling path to the opposite conclusion. This should tell you following each narrative is an exercise in thinking in a particular way rather than the royal road to truth. In reality, most of our lives are guided by our immediate experience and intuitive sense of the world—what philosophers from Europe called Phenomenology in the late 19th century. What this means is that that we can be taught some philosophical truth, affirm its veracity, and then, without fail, completely ignore it within moments. Experience outweighs truth nearly every time. Let me give you two quick examples.
Most of you have seen the Muller-Lyer illusion shown in the figure. Logically, you know that the two lines are really the same length. There are various ways to verify this. You can measure the lines. You can also cover the arrows so that the lines look the same. There are adaptive evolutionary reasons why our brains interpret the lines differently based on the kinds of arrows attached. But knowing all of this changes little. No matter how many times you see this illusion it is compelling because your immediate experience doesn’t care what you know logically most of the time.
Here’s a second example: How do you know whether everyone around you has a mind and isn’t really an android, Cylon, or some other kind of automaton that appears human but isn’t really. You never get to experience any mind but your own. Logically, you have no right to treat everyone around you as if they have a mind because you can’t tell if it is an illusion or not? Maybe the Turing machine has been perfected. We don’t know.
Let’s say a philosopher makes a compelling argument that the only mind you know exists for sure is your own. It doesn’t’ matter. You’ll still go to the McDonald’s drive-in and give your order to a teenage cashier as if he really has a mind. We can’t help but take what Dan Dennett called the intentional stance. We see minds everywhere because we are built to.
It is impossible to take a materialistic view of the universe (i.e. the view that there is nothing but physical material in the world, atoms bouncing off one another in perfectly predictable patterns) and not come to the conclusion that free will is an illusion because your will must ultimately be caused by events in your physical brain which were caused by previous events in your brain, body, environment and so on. It makes no sense to talk about a will that is disconnected from causal chains of biological events.
Given a materialist view of the universe, it makes no sense to talk about consciousness or experience at all. We have absolutely no idea what it is about the three pounds of mush between our ears that allows it to perform this trick of being conscious. If you damage one spot in visual cortex, a person will cease to see motion. If you damage another spot, they may lose the ability to see things in the right side of their visual field. But we have no idea why those regions cause us to have conscious experience of motion or the right side of the visual field in the first place. Knowing that an engine can’t run without a particular part is not the same as knowing why it can run because of that part.
I am a neuroscientist and so 99% of the time I behave like a materialist, acknowledging that the mind is real but fully dependent on the brain. But we don’t actually know this. We really don’t. We assume our sense of will is a causal result of the neurochemical processes in our brain, but this is a leap of faith. Perhaps the brain is something like a complex radio receiver that integrates consciousness signals that float around in some form. Perhaps one part of visual cortex is important for decoding the bandwidth that contains motion consciousness and another part of the brain is critical to decoding the bandwith that contains our will. So damage to brain regions may alter our ability to express certain kinds of conscious experience rather than being the causal source of consciousness itself.
I don’t actually believe the radio metaphor of the brain, but I think something like it could account for all of our findings. Its unfalsifiable which is a big no-no in science. But so is the materialist view—its also unfalsifiable. We simply don’t know how to reverse engineer consciousness. Saying that the complexity of the brain explains why we are conscious is just an article of faith—it doesn’t explain anything. We don’t know why our brains are associated with conscious experience and nothing else in the universe besides brains seems to be. Maybe rocks have consciousness but no way of showing this. I don’t believe this—but again, I can’t prove its false.
If we acknowledge just how much we don’t know about the conscious mind, perhaps we would be a bit more humble. We have so much confidence in our materialist assumptions (which are assumptions, not facts) that something like free will is denied in principle. Maybe it doesn’t exist, but I don’t really know that. Either way, it doesn’t matter because if free will and consciousness are just an illusion, they are the most seamless illusions ever created. Film maker James Cameron wishes he had special effects that good. So we will go on acting like free willing creatures no matter what. Its what we're built to do.