A couple of weeks ago I heard Brian Greene state there is no scientific basis for free will. It was a powerful statement because he made it quite categorically and tersely. And it really jolted me into thinking about this longstanding philosophical problem that I hadn’t really spent much time thinking about since College. The timing couldn’t have been more perfect as I have been studying up on neural networks.
As I have thought more about it I find myself agreeing with Brian. At any one moment in time our brain, however amazingly large and complex it is, represents a gigantic probabilistic computer that turns a set of inputs into outputs. The probabilistic part means that even if the same brain were to be presented with the same inputs it might produce a different observed output (given the complexity involved this is a complete hypothetical, as the “same” brain implies each of nearly 100 billion neurons in the same state). What is true though is that the probability distribution over outputs is entirely encoded in that brain. And hence there is no free will.
Let’s look at a concrete example. I wake up in the morning and want to decide between having tea or coffee for breakfast. It is my brain that makes this decision. There is no “me” that’s separate from my brain. My brain has been trained over 46 years and has encoded in it longterm preferences and evaluation of short term inputs (eg it turns out there is only Mint tea in the house). If we hypothetically could put me into the exact state repeatedly, I might choose tea some of the time and coffee some of the time due to the probabilistic nature of neurons firing and possibly even due to quantum uncertainty. But: the probability distribution over tea and coffee is fixed for that moment in time. And as a result I don’t exercise free will in picking one versus the other. My brain simply does its thing and I wind up drinking either coffee or tea. The same logic applies to all decisions we make in life. From the mundane to the enormous.
Viewing the world through this lens has some pretty big implications. Let me start though with what it does not imply. It does not imply that people shouldn’t be held responsible for their choices and actions. There is no “my brain made me do it” defense because, well, you are your brain! And knowing about negative consequences of certain actions still very much matters in this world view because it will impact how brains choose.
What it does imply though is that our lives are hugely path dependent. In the extreme it is entirely possible in this view of the world that you could have a “sliding doors" moment in your life: a single tiny event that means you wind up in a very different place. Why? Because life overall is likely to be a chaotic system in which tiny shifts in initial conditions can lead you to vastly different outcomes. That in turn implies lots of things for society and how we live our lives. For society it is the strongest possible argument for investing in education and social security for all. Personally it means being grateful for the people who are or have been a positive influence on us and being such an influence for others.
What about self improvement? This view should not be confused with saying that you are who you are and can’t change. It simply says you are who are you are in any given moment. So you cannot appeal to free will to say that person x should choose to become a better at something. Person X’s brain is making that choice based on what has been learned by it so far and the inputs presented to it at that moment. And so the future path of person X depends on the choice made by X’s brain and on the things that happen to x and the people he or she encounters or interacts with.
What about the sensation of free will? Do we actually experience ourselves as possessing free will? I used to think that we do. But I am not sure anymore. Go back to any decision that you have made and ask yourself whether you can recall the moment where you “willed” that decision. When I do this honestly I don’t seem to be able to recollect or pin down that moment — rather my subjective feeling is one of the decision having “happened.” Admittedly this is all highly subjective and quite possibly colored by my current thinking about there not being free will.
It is not very far fetched to think that the related concepts of free will and individual freedom are quite highly socially constructed. The free will debate is as old as the Greek philosophers with early signs of it in Aristotle and Epicurus. But prior to that Greek myth and tragedy are full of characters where some choice is central to their fate but usually appears highly pre-determined. It seems then that the early awakening of thoughts of free will and personal freedom are coincident with early science and “freer” forms of society.
Believing that there is no free will in the strict sense is not a fatalistic perspective on life. In fact it has had the opposite effect for me. I have found it to be quite empowering. If you want to change yourself you have to change your brain. Even just having that knowledge is already changing your path through life.
PS: Brian was kind enough to read an early draft of this blog post and added this thought: “Now, the one footnote on all this is that in Quantum Mechanics we’ve not solved the quantum measurement problem—we don’t have a fully agreed on understanding of how reality goes from probabilities to definite outcomes. Is it in principle possible that free will slips into that process? Logically, yes, that is possible. Hard for me to believe that’s how the universe works, but it is possible.”