I have noticed that some proponents of free will actually define it as what I term freedom of choice. Freedom of choice refers to the rational agent’s ability to choose between multiple courses of action in accordance with their will, independent of exterior factors. This is distinct from freedom of action and thus it is unimportant whether or not the agent is physically able to carry out the planned actions. It is clear that humans generally do have freedom of choice: we are free to make decisions based on our will. If this is what is meant by free will, then indeed humans have free will. However, freedom of choice alone is not consistent with our intuitive understanding of free will. For instance, a basic requirement of free will is that the agent’s decisions are not deterministic; they have the freedom to do otherwise. Despite this, freedom of choice is independent of whether or not the agent is deterministic. Thus, freedom of choice alone is insufficient for free will. For instance, suppose that the universe is deterministic and the psychological state of a human is strictly based on the biological state of their brain. In principle, we would always be able to predict their decision, were we able to simulate the universe in sufficient detail. Their will is deterministic and so the choice they will make ultimately must also be. Note that this does not affect the agent’s ability to base their decision on their current will. Hence, while they do not have free will they still have freedom of choice. Whether or not the universe is actually deterministic is irrelevant for this argument. The point is simply that freedom of choice alone is insufficient for free will: it does not fulfill the criteria that the agent could have done otherwise. Free will therefore requires freedom of will in addition to freedom of choice. This refers to the agent’s ability to determine their own will, fully free of any outside influences.
There is no mechanism by which rational agents can have freedom of will. The will of each human is their own, but we ultimately do not determine them ourselves. Our biology and environment play important roles in shaping our minds. In turn, we make decisions which affect our biology and all aspects of our environment throughout our life. Hence continuous complex interactions between our biology, environment, and mind determine who we are as a person at large, what preferences we have, and ultimately what decisions we will make. In essence, our will is shaped by factors outside of our control. Of course our mental state itself modulates the changes it undergoes over time, but freedom of choice cannot free our will. The complex interactions that shape our mind begin at birth. The initial conditions of our birth and development are fully independent of our will. In fact, the notion of an agent being the sole determinant of their mental state is contradictory: supposing that we have full control over the initial properties of our mind supposes that we already had a mind to have preferences with. Thus, the properties of minds must ultimately be determined by external factors. In summary, rational agents may have the ability to make decisions based on their will (freedom of choice), but cannot be the sole determinant of their own will (freedom of will).
I will now refute two common mechanisms proposed by free will advocates to allow for free will. Firstly, the stochastic nature of quantum mechanics is often cited as a means by which the universe can be considered non-deterministic. This is true, at least for very small systems. However, it is actually unimportant whether or not quantum mechanical fluctuations result in any appreciable uncertainty in macroscopic systems. This is because the argument is based on the notion that a lack of determinism would prove the existence of free will. However, more accurately an agent being non-deterministic is a necessary, but not sufficient condition for free will. This mechanism merely introduces randomization into the decisions and will of the agent, this is not the same thing as freedom of will or choice. In fact, this randomization could potentially infringe upon their freedom of choice. To make this idea clearer, consider a game of roulette. Suppose that each number on the wheel is assigned to a different choice. The roulette wheel in spun and the agent makes the choice corresponding to the number the ball stops on. We could also play this game to determine the state of will of an agent, to the same effect. It is clear to our intuition that the choice and will of the agent are not free, though the outcome is unpredictable. This analogy could be criticized on the basis that it does not properly capture the nature of our non-deterministic decision-making. In particular, the spinning roulette wheel is independent of the agent, whereas the uncertainty of quantum mechanics directly involves the agent since it acts directly on their brain. Nevertheless, whether or not the random event directly involves the agent does not change the situation in any meaningful way. We could involve the agent directly in the random event by having them spin the roulette wheel, for instance. To our intuition it is clear that the outcome selected by the wheel would still be random and not represent free will.
Another mechanism sometimes suggested to allow for free will is the soul. Its metaphysical nature makes it an attractive mechanism, if its existence is assumed. Since it is non-physical, it would not be limited by physical law and certainly would not have to be deterministic. This property is often asserted to be sufficient to allow for free will, but as I argued above determinism is necessary, but not sufficient for free will. The soul merely provides another input into the will, it does not free it. By analogy, consider the genetics that we are born with. They have a profound effect on our biology, brain, and ultimately our mind, but do not free our will. We are born with our genetics, they are beyond our control. Observe that just as each human is born with a genome, so too would they be born with a soul. Therefore, the soul is not a viable mechanism through which freedom of will can be achieved.
In summary, freedom of will is an important requirement of free will because it provides agents with the ability to do otherwise. I have shown that rational agents may have freedom of choice, but not of will. Thus, they cannot have free will.