Brains, Choices and Free Will
I hope I’ll be forgiven for bringing up the topic of free will yet again, because in a sense it is a ridiculous question. The most cogent statement I have found on free will is this:
We need not enter into a philosophical debate between free will and determinism in order to decide how to act. Either we have free will or it is determined that we behave as if we do. In either case we make choices.(1)
The point of a philosophy for real life is to figure out how to make those choices, not whether we have the ability to do so. The fact is, we all act as if we have free will, regardless of what we say we believe about it.
In another sense, however, it is not ridiculous. In a recent psychology experiment subjects were found to be more prone to cheating after having been exposed to arguments denying that we have free will.(2) Neuroscientists debate how findings that much of our behavior is determined should affect judicial concepts of blame, responsibility and punishment: if we can’t help what we do, we don’t deserve blame, so what role should punishment play? (The answer is to go for rehabilitation to modify future behavior instead of punishing past behavior.)(3) Whether or not we believe we have free will does have consequences; hence, we need to try to resolve the issue.
The debate about free will is whether we have it and how it works if we do. It is a conundrum because we appear to live in a deterministic universe. Ever since antiquity or earlier people have noticed that some aspects of their world recur with great regularity. Apply fire to something, and it invariably gets hotter. The sun always rises in the east and sets in the west. Through the application of the scientific method of discovery we have found laws of nature that consistently operate in the same way, so much so that we say that physical nature is determined by those laws. By “determined,” I mean that given a configuration of physical elements and the invariant laws of nature, we can confidently predict precisely what will happen next. The argument against free will says that if all of nature is determined, and if we are part of nature, then we are determined. We think we have the ability to choose freely what we do, but that ability is an illusion.(4)
To assess this argument we need definitions of the concepts of determinism and free will.
The definition of determinism is easy. Determinism, according to philosopher Daniel Dennett, quoting Peter Van Inwagen, “is the thesis that ‘there is at any instant exactly one physically possible future.'”(5) On this view, events succeed each other according to rigid, predetermined laws; and if we knew enough about the facts of the universe at any given time and the laws of nature, we would know with certainty what would happen next.
The definition of free will is a little more complex. First let’s take “will.” Philosopher Robert Kane, who has made a career of studying the issue, lists three meanings of the term:(6)
- What we want, desire or prefer to do. This is called appetitive will, because it has to do with our appetites.
- What we choose, decide or intend to do. This is called rational will, because it has to do with reasoning and deciding.
- What we try, endeavor or make an effort to do. This is called striving will.
All three are teleological, oriented to an end or purpose (telos in Greek). In using our will we desire, intend or try to make something happen that is not happening yet, or to make something that is already happening continue to happen. They are all oriented to the future. Clearly we human beings have will in all three senses.
(Parenthetically we might ask whether animals have will. Certainly even the most primitive of animals seem to have desires and to make efforts to approach or avoid things in their environment. Whether they have any rationality depends on how complex they are. It is hard to imagine a single-celled amoeba envisioning possible courses of action and choosing among them. It is not so hard to imagine an elephant or an ape or a whale doing so. I suspect that, like most of reality, the ability to think and choose ranges on a continuum from minimal to maximal; and humans are on the maximal end of the scale.)
The question is whether the will we have is free. I adopt Kane’s definition of free will:
Free will … is the power of agents to be the ultimate creators (or originators) and sustainers of their own ends or purposes. … To will freely … is to be the ultimate creator (prime mover, so to speak) of your own purposes.(7)
Will has to do with wanting, choosing and striving to attain ends or purposes. We humans are very good at achieving goals, at accomplishing our ends and purposes. But who or what gets to set the goals? To say that our will is free is to say that at least in some cases we ourselves, not something other than or external to us, choose what ends or purposes we strive for.
We can list the philosophical positions regarding free will by combinations of assertions about determinism and about free will. Let’s represent the proposition that the world is entirely determined as D and the proposition that it is possible to have free will as F. To make sure we have all our bases covered we can put them together systematically and label each combination. Then we can decide which combination most accurately describes reality. Here are the combinations:(8)
|D true||F true||Compatibilism|
|D true||F false||Hard Determinism|
|D false||F true||Libertarianism (a philosophical, not a political, term)|
|D false||F false||Hard Incompatibilism|
We can immediately rule out the first two. It is not the case that all of nature is determined. Quantum physics has demonstrated as well as anything can be demonstrated in science that at the tiniest level of reality events are indeterminate. By this I mean that the outcomes of events cannot be predicted in advance, except in statistical terms. An initial configuration of things and forces does not determine a specific subsequent configuration. Instead it has the possibility of evolving into more than one configuration. In the world that we experience, only one of those possible configurations will actually be observed to happen, and we cannot predict in advance which one it will be. Mathematics can describe the probability of a range of outcomes, but cannot predict a single outcome. Please see my blog post “Entangled!” for more details. The thesis that there is at any instant exactly one physically possible future is simply false.
So now we have to decide, in a world that is not fully determined in advance, whether and in what way free will is possible. I have hinted at an answer in another blog post, “Beyond the Causal Veil,” in which I describe how quantum indeterminacy operates inside the brain.
To summarize: The brain does its work by means of transmitting electrochemical impulses through neurons. A neuron receives many incoming impulses from other neurons and sends out impulses to many other neurons. Some of the incoming impulses are excitatory, tending to make the neuron “fire,” or send out an impulse; some of them are inhibitory, tending to make the neuron fail to fire. (A neuron either fires or it does not; there is no in-between state.) When a neuron fires, neurotransmitter chemicals travel from one neuron to another across the synapse between them. What causes the neurotransmitters to be released into the synapse is the entry of calcium ions into nerve terminals. If enough calcium ions hit their receptor sites within a nerve terminal, the terminal releases the neurotransmitters; otherwise it doesn’t. Calcium ions and the channels through which they travel are small enough that quantum indeterminacy is in play. Calcium ions might or might not hit their triggering sites; hence, a given neurotransmitter might or might not be released; hence the receiving neuron might or might not get excited (or inhibited).(9)
Since brain functioning is the physical aspect of how we perceive, move, react and make decisions, this means that our decisions and actions are not fully determined by what has happened in the past.
So if we are not fully determined, then we have free will, right? Well, maybe not. There are some objections from those who say than that even in an indeterministic world we still have no free will. (This is Hard Incompatibilism in the matrix above.)
The most common objection is that if our actions are caused by randomness then we are just as unfree as if they were caused by determinism.
The sort of indeterminism afforded by modern physics is not the sort the libertarian needs or desires. If it turns out that your ordering soup is completely determined by the laws of physics, the state of the universe … and the outcomes of myriad subatomic coin flips, your appetizer is no more freely chosen than before. Indeed, it is randomly chosen, which is no help to the libertarian.(10)
My response is this: what matters is not the outcome of a single quantum event, but the overall pattern of many of them. What appears to be random when you look only at individual events reveals patterns when you look at them in aggregate. Micro-units of quantum indeterminacy cohere into larger arrangements that are not random. We can see this on the physical level in the interference pattern, the stripes of lightness and darkness, in the double-slit experiment.(11) When we are considering human agency and will, we find patterns as well, patterns that are best described in agential terms, as I said in the first of this little series. The patterns of beliefs, desires, aversions and intentions that we ascribe to ourselves and others are at a higher level than the individual neural events which underly them, and obey different laws.
Patterns of calcium-ion events within a nerve terminal are inputs to patterns of nerve terminals releasing neurotransmitters, which are in turn inputs to the firing of adjacent neurons. Activities of individual neurons are, as Ray Kurzweil has described, inputs to yet higher-level assemblies of pattern recognizers composed of multiple neurons.(12) The nesting of patterns within patterns continues up to higher and higher levels of complexity, at the apex of which we recognize ourselves and others as agents motivated by beliefs, desires, intentions and plans.
Another claim is that my account of neural functioning is misleading, that quantum indeterminacy does not propagate upwards to observable behavior.
Given the high concentration of calcium ions in the terminal, it’s extremely likely that the net effect is zero—for every ion pushed away by a quantum event, another is pushed toward. If this were not the case, we would be dying of heart attacks before reaching puberty, since neurons that drive the heart muscle must be subject to the same quantum effects.
It’s an example of biological fault tolerance. Critical systems like neurons—cells in general—are resilient to error through physical redundancy (multiple vesicles, multiple binding sites per vesicle, multiple calcium channels, thousands of available calcium ions per neuron).(13)
Good point. If quantum uncertainty underlies all brain functioning, why does most of that functioning happen in foreseeable, regular ways? Why do some patterns of neural firings—those that govern our heartbeat, for instance—happen quite predictably, while others, such as those that correspond to our making a free choice, do not?
There is a saying in brain science, “cells that fire together wire together.” When the firing of neuron A is, repeatedly and persistently, input to neuron B’s firing as well, a metabolic change takes place such that neuron A becomes more likely to be effective in causing B to fire.(14) The brain, composed of living cells, changes (a process called brain plasticity)(15) to make the repeated pattern more likely. In such a case the probabilities involved in neural firing are adjusted to make it extremely likely that the regularity will persist. That’s how come our heartbeat is not interrupted by quantum fluctuations.
But this does not happen in cases of free choice because there are conflicting patterns of cells firing together. Here is a common example: suppose you are hurrying to a very important meeting with a client and your boss, a meeting that will have a big impact on your career. You pass a person lying by the road injured and bleeding. You want to be compassionate and stop and help the bleeding person, but you also want to be on time for your meeting. In such a case your goals, ends and purposes are in conflict. There is no routine pattern of neural firing that is so highly probable as to be determined and certain.
In this case, where there is no future outcome that is far more highly probable than any other, the effect of the quantum indeterminacy at the lowest level is magnified rather than damped out. When you must make a choice, the choice is not determined in advance. Nor is it merely random. Conflicting emotions and thought process go through your mind. You have good reasons for hurrying to your appointment, and you have good reasons for stopping to help. You have to choose, and it is not just a matter of flipping a coin.
Kane lists three criteria by which we recognize that a choice is made freely, on our own:(16)
- We have good reasons for our choice.
- We choose as we do for those reasons.
- In choosing we define ourselves as a being who wants to act for those reasons more than for any others.
These three conditions are satisfied in either case, whether you hurry on or stop to help. Whichever choice you make, afterwards you can legitimately say that you, not your brain cells, made the choice, because you had good reasons for your choice and you acted for those reasons. And that is true even though you did not know and could not possibly know ahead of time which choice you would make.
That’s how free will works in an indeterminate universe, not by magically flouting physical laws, but by conforming to them.
Note carefully the third condition. When you choose one way or another, you are making it more likely that you will choose the same way if a similar issue comes up again. You reinforce certain neural patterns, making them more likely to fire together in the future. You help create your future self.
What kind of choices do you want to make? What kind of person do you want to be?
(1) Fisher and Ury, Getting To Yes, p. 53.
(2) Tierney, “Do You Have Free Will? Yes, It’s the Only Choice.”
(3) Greene and Cohen, “For the law, neuroscience changes nothing and everything.”
(4) Historically determinism has also been associated with the idea of a supernaturally powerful God who makes things happen, but I am ignoring that question for now.
(5) Dennett, Freedom Evolves, p. 25.
(6) Kane, The Significance of Free Will, pp. 26-27.
(7) Ibid., p. 4.
(8) Wikipedia, “Free will.”
(9) See Meacham, “The Quantum Level of Reality,” for a more complete exposition of the quantum aspects of neural functioning.
(10) Greene and Cohen, p. 1777.
(11) Meacham, “The Quantum Level of Reality.”
(12) Kurzweil, Ray, How To Create a Mind, p. 80.
(13) Bjerke, Gary, “A Response To ‘Beyond the Causal Veil.'”
(14) Kurzweil, Ray, How To Create a Mind, pp. 79-80.
(15) Chudler, Eric H. “Brain Plasticity: What Is It?”
(16) Kane, The Significance of Free Will, p. 137.
Bjerke, Gary. “A Response To ‘Beyond the Causal Veil.'” Online publication http://files.meetup.com/119694/MDG_FREE_WILL_03_11_13.pdf as of 5 March 2013.
Chudler, Eric H. “Brain Plasticity: What Is It?” Online publication http://faculty.washington.edu/chudler/plast.html as of 11 March 2013.
Dennett, Daniel C. Freedom Evolves. New York, Penguin Books, 2003.
Fisher, Roger, and William Ury. Getting To Yes: Negotiating Agreement Without Giving In. NY: Penguin Books, 1991.
Greene, Joshua and Jonathan Cohen. “For the law, neuroscience changes nothing and everything.” Philosophical Transactions of the Royal Society of London B (Biological Sciences), Vol. 359 No. 1451, pp. 1775-1785. Online publication http://rstb.royalsocietypublishing.org/content/359/1451/1775.full.pdf as of 7 March 2013 and http://www.wjh.harvard.edu/~jgreene/GreeneWJH/GreeneCohenPhilTrans-04.pdf as of 08 October 2010.
Kane, Robert. The Significance of Free Will. Oxford: Oxford University Press, 1998.
Kurzweil, Ray. How To Create A Mind: The Secret of Human Thought Revealed. New York, Viking: 2012.
Meacham, Bill. “The Quantum Level of Reality.” Online publication http://www.bmeacham.com/whatswhat/Quantum.html.
Tierney, John. “Do You Have Free Will? Yes, It’s the Only Choice.” New York Times, March 21, 2011. Online publication http://www.nytimes.com/2011/03/22/science/22tier.html as of 23 March 2011.
Wikipedia. “Free will.” Online publication http://en.wikipedia.org/wiki/Free_will as of 4 March 2013.