I submitted the following as my final paper in a philosophy class. The official title was “On the Existence of Free Will”
There is, ostensibly, a great tension between our notion of free will and that of determinism. Determinism is the idea that every event is caused by some previous event. That previous event determined exactly what its effect would be with no wiggle room. Under determinism, the state of the universe in its entirety at this moment was the direct result of its state at a previous moment. Similarly, there is only one possible state the universe can assume at any given time in the future, which is determined by its state now. A universe governed by Newtonian mechanics is one example of a deterministic universe. One thought experiment which elucidates the implications of determinism is that of Laplace’s demon. Laplace’s demon is an extremely intelligent hypothetical agent who somehow comes to know the state of the universe in its entirety—down to every last particle. With its infinite computational power, the demon is able to predict with 100% accuracy the state of the universe at all future times (Dennett, 2003, p. 28). Under determinism, it seems, the future is fixed.
Our everyday notion of free will relies on multiple possibilities. Whenever I make a decision, I experience this decision as a state in which there are multiple genuine possibilities before me. I—as the free agent—select which of those possibilities becomes actual. For example, when I wake up in the morning I could have regular coffee, decaf, something else entirely, or nothing at all. Before I make my decision, all these seem like genuine possibilities. Once I make my decision and act on it, one of these possibilities becomes actual. I may experience regret about my decision. If I decide to drink decaffeinated coffee with my breakfast and later feel excessively drowsy, I may express regret at wasting my money on such an infernal beverage. It appears to me that I could have made a different decision—that there were several ways the state of affairs could have evolved and my choosing influenced that evolution.
How then are we to reconcile the two positions? Must we give up free will? The implications of this would be dire. We hold one another accountable for our actions based on the assumption that we all act as free agents. Our sense of justice is based on the idea that people should be held responsible for what they freely choose to do. If there is no free will, it would seem that people do what they do simply because there was some brute cause for their actions and our sense of justice is misguided.
Should we instead give up on determinism? Perhaps there are some things which are uncaused, and perhaps this gives room for free will? It is worth noting that our current understanding of physics is non-deterministic. Quantum mechanics, which describes the behavior of subatomic particles, states that these particles exhibit genuinely random behavior. There is nothing that causes an electron to be in one particular place rather than another, there are only probabilities associated with its location. Under quantum mechanics, there is genuine randomness in nature, and hence more than one possible future (Griffiths, 2005, pp. 2-5). This means that not even Laplace’s demon could predict the way a quantum mechanical system will evolve. Could this be the savior of free will? It would seem that the statement “when I make a decision, I could have chosen otherwise,” is true.
Alas, I fear this line of thinking leads us to absurdity. If I started running around screaming like a maniac, surely you would ask me why I did so. If further investigation revealed that there was no causal account, and my behavior was the result of a purely random event, no one would say that my action was free. To give another example, suppose my mother is cutting fruit in the kitchen. When I walk by, she turns around and stabs me in the neck, killing me. During the subsequent murder trial, conclusive evidence is found that her arm moved randomly, with no signal from her brain. Should the judge hold her accountable? I would say, “Absolutely not”. The event was entirely random, and was not under the control of my unsuspecting mother.
It would seem that both determinism and indeterminism do not allow for free will. Indeterminism allows for multiple possible futures, but does not seem to agree with our intuitions about free will. This is because in the cases of both determinism and indeterminism, an agent’s actions are caused by something other than the agent itself. In the case of determinism, the agent’s actions are caused by the conditions before the agent’s birth. In the case of indeterminism, they are caused by these conditions plus an element of randomness. Free will would seem to require both that we could have done otherwise, and that we are the causes of our actions. Is such freedom possible?
Before I attempt to answer this question, I will describe the conceptual foundation which forms the basis for my answer. This is a kind of radical physicalism. Everything is physical. There are no souls, spirits, gods, or other immaterial beings. The entirety of existence could, in principle, be described by a sufficiently advanced science. Some will undoubtedly find this physicalism controversial. While this is a position I firmly hold, I will not argue for it here. Rather I will argue its implications in the debate on free will. My position on free will relies on the proposition that everything we know ultimately reduces to something physical. This includes consciousness, ideas, emotions, and desires.
It is worth spending some time clarifying what I mean by “reduces to something physical”. To do this, I will explain the concept of levels of abstraction as it pertains to my discipline, electrical engineering.
A computer is a marvel of modern engineering. But how was it designed? No engineer has ever designed a computer in its entirety from the ground up. That would be a fool’s errand. Such a contraption is vast and complex to the extent that no single person understands every aspect of how it works. First, an engineer specializing in physical electronics designs the transistors, diodes, and other devices that form the lowest level of abstraction. Another engineer uses these to create logic gates for use in computation and flip flops to be used for memory. Another engineer uses these as building blocks to design the building blocks the next engineer uses. A software engineer, working at the highest level, designs programs using abstract concepts which in no way resemble the physical constituents of the computer. As we ascend the levels, our ontology changes. Each successive level of abstraction is explainable in terms of the previous level. When a computer program, such as the word processor I am using right now, executes, the behavior of the computer could be described in terms of the trajectories of a vast number of electrons through silicon and metal at the lowest level. However, such a description would be extremely convoluted and would likely give no useable insight into how the program works. When a software engineer describes a program in software jargon, each term they use is ultimately reducible to some complex movement of electrons. Take note of what the word “reduce” means in this context. To say that software engineering reduces to physical electronics most emphatically does not mean that the software jargon is useless or invalid; far from it. It does mean, however, that physical electronics is most fundamental in describing how a computer works. Each level is a valid way of describing what a computer does. Each successive level makes approximations and simplifications which leave out some details of the previous level, but make the information more manageable for larger scale design. The boundaries between levels are arbitrary, so long as each is consistent with empirical data on what the system does.
I have used the engineering example to motivate the validity of the concept of levels of abstraction. Within this field, this concept is not the least bit controversial. No one doubts it is true that a word processor creates text documents, even though their existence is reducible to other things, such as magnetic dipoles on a hard drive and pixels on a screen.
The same, I hold, is true of nature. All our descriptions of nature ultimately reduce to physics. Animal behavior is reducible to cellular biology. That is, everything an animal does can—in principle—be explained in terms of the interactions of its cells. Cellular biology is reducible to chemistry, and chemistry is reducible to physics. As we descend the levels of abstraction, we find a description of the constituents of the previous levels.
I am now in a position to make a claim about free will. Free will exists as a high level abstraction. It is an approximation which is applicable to our daily lives, but breaks down if we look more closely.
At a low level, my actions are caused by deterministic and probabilistic causes. These include such small details as temperature fluctuations in the room, random changes in the signal strength in my neurons, and pressure changes in my cerebrospinal fluid. Laplace’s demon could trace all the physical causes of a person’s actions down to the last molecule.
For the purposes of our daily lives, however, such a detailed model of human behavior would be utterly unworkable. It would be even more convoluted and cumbersome than describing a computer program via the movement of electrons. We must make a high level model of human behavior. In this high level model, we approximate the will as a single, indivisible entity. This approximation states the following:
1) The will is efficacious—it causes things to happen
2) Whenever the will causes something to happen, it could have caused otherwise
3) An action is free when the will is a sufficiently significant cause of that action
According to 2), this model takes for granted that we could have done otherwise. When I make a decision I see multiple possibilities before me and cause one to become actual. If we take low level details into consideration, each of these possibilities is a mere epistemic possibility—a case where I do not have enough information to know which future will happen (for instance, about the details mentioned in the previous paragraph). At a high level, we leave these details out and approximate the epistemic possibilities as genuine possibilities about what could have happened. This is the sense in which we could have done otherwise.
According to 3), an action is free if it is a sufficiently significant cause of that action, but not necessarily the only cause. For example, when someone persuades me to do something, my action was caused by my will and by the other person’s argument. If, on the other hand, they coerce me to do something, my will was a negligible cause of my action so I should not be held morally responsible. I will leave the question of exactly how significant the will must be to judges and juries.
If free will as an approximation sounds unsatisfactory, it would pay to remember that many other things are high level approximations. These include: cats, airplanes, trees, computers, chairs, coffee shops, and just about anything we interact with on a daily basis. Approximations are made even when we refer to a simple object such as a pencil. We model the pencil as an object with a definite boundary between itself and the air surrounding it. At a lower level, however, this is not so. If we look at the surface of the pencil at the microscopic level, we find there is no non-arbitrary way to draw an exact boundary between the atoms that compose the pencil and the atoms of the air. When we model the behavior of a cat, we make much more elaborate approximations. For instance, the idea that the cat desires tuna is a fairly simple idea. But the concept of a desire is an approximation of tremendously complicated brain states. Free will exists just as surely as people, cats, and pencils.
If the sort of freedom you crave is a fundamental and irreducible law of nature, you will be sorely disappointed. However, nature has provided us with a sort of free will sufficient for our purposes—namely planning and moral responsibility. Since moral responsibility is a concept that relies on the existence of people who are high level abstractions, it is a high level abstraction as well. When we see that a person’s will caused something to happen, we can then assign the appropriate praise or blame. Likewise, when I am considering whether or not to follow my ambitions and put effort into achieving my life goals, it would make absolutely no sense for me to give up on the grounds that everything is determined (or random, as the case may be). To do so would be to think at the wrong level of abstraction.
You might say I am stubbornly trying to have my cake and eat it too. This may be true, but I insist I am doing so by refusing to lose the forest for the trees. The forest of free will is composed of the trees of physical causes. To say “there is no free will, only physical causes of one’s actions” is tantamount to saying “I can’t see the forest, there are all these trees in the way!” I will let the incompatabilists continue to lose sleep over this issue while I wake up feeling well rested, ready to freely choose what to have for breakfast (perhaps cake?).
Dennett, D. C. (2003). Freedom Evolves. New York: Penguin Putnam Inc.
Griffiths, D. J. (2005). Introduction to Quantum Mechanics (Second ed.). Upper Saddle River, NJ: Pearson Education, Inc.
McLaughlin, B., & Bennett, K. (2011, November 2). Supervenience. Retrieved May 8, 2012, from Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/supervenience/#4.3
 I will continue to use the term “level of abstraction” the way engineers and computer scientists use it. Some might find the word “abstraction” troublesome here. A philosopher might prefer “level of reality” or “level of supervenience” (i.e. the properties at a higher level globally supervene on the properties at a lower level (McLaughlin & Bennett, 2011)), it makes no difference for my argument.
 This is controversial, but I will not argue this further for the purposes of this paper. To do so would be to enter into the messy debate on the nature of morality.