In philosophy, one can often find hypothetical situations to be the basis of philosophical reasoning. Used often in arguments or critiques, what is commonly known as a thought experiment can be a useful tool in determining one's stance on a subject. Much like a regular experiment, they are all about the observation of a circumstance that has been set in a particular way. The difference, however, is that a thought experiment is purely set in the mind. It is a completely hypothetical examination of a proposed situation. This method of study has been used in all areas of philosophy but one that it has been particularly helpful with is the philosophy of the mind, specifically freedom of the will. A famous example of a thought experiment dealing with freedom of the will is called Locke's Voluntary Prisoner.

     This thought experiment starts off with the premise that there is a sleeping man, and whilst unconscious he is brought into a room. In this room a person awaits, and it is someone that the sleeping man would be delighted to see and speak to. After the man is brought unaware into this room it is locked and he cannot get out. When he wakes, however, he is happy to see the person in the room and prefers to stay with them rather than leave the locked room. The question this situation proposes is whether the man's stay is voluntary.

     When evaluating this problem there are many aspects to consider. Does his being placed in this situation involuntarily change the amount of freedom in his decision? If he is content with a decision made for him but there is no other possible choice, can he be considered to have had any control at all? And if he does not have any control over his own circumstances, is it even possible for his stay to be voluntary? This dilemma challenges people to revise their thinking on what makes a choice voluntary and question how one should define free will.

     To truly begin to understand the concept of free will and how to apply this understanding to the problem of Locke's Voluntary Prisoner, it is necessary to become familiar with a point of view called determinism. Determinism is the belief that there is only one physically possible future at any given time. In this view, a future event must rely on a description of the past and an account of the relevant laws of nature for it to be possible. An excellent example can be found in A Brief Introduction to Philosophy, a textbook written by Yoni Porat. It states “Determinism makes the claim that if I take a pot of water and I put it on my stove, and heat it to 100°C, it will boil. This is because the laws of nature (in this case, water that is heated to 100°C will boil) and the events of the past” (pg.174) In this example it is demonstrated that the only physically possible future is that the water will boil when heated to 100°C. This is because there is evidence from the past and from the laws of nature that the water boiling at 100°C will always be the only possible result. But it is important to also know about the opposite of this view called indeterminism.

      Indeterminism is the denial of determinism and is required to make free will possible. This is because the possibility of free actions requires that there be more than one future physically possible, which determinism rejects. Theoretically, however, a valid argument could be that the two are not mutually exclusive and that it is at least possible for a person to have control outside of the deterministic criteria. But first a basic understanding of the types of freedom is needed to understand how that would be possible.

      Although determinism overall is seen as incompatible with freewill, there happens to be multiple viewpoints on what freedom is. There are three distinct viewpoints on freedom that most theories fall into. Each one has been compared to determinism closely to try and determine if it is impossible for free will to exist in a deterministic world.

     The viewpoint called easy freedom is easy to understand. It is simply doing what you want to do. An example from the textbook, A Brief Introduction to Philosophy explains it as: “if you wanted to walk across the room, right now, and you also had the ability, right now, to walk across the room, you would be free as you could do exactly what you want to do.” (Porat, pg.175). This viewpoint at first seems hard to deem incompatible with determinism. A group of philosophers called compatibilists argued that free will is the ability to act without external hindrance and that determinism does not interfere with this. However, a compelling argument has persuaded many otherwise. It is called the consequence argument and when simplified states that one can never act without hindrances because their actions are always caused by past events and the laws of nature. When considering this argument, easy freedom is not compatible with determinism because in a deterministic world there will always be hindrances on potential actions.

     Another viewpoint of freedom is called the alternative possibilities viewpoint. It is like easy freedom and dictates that free will requires the ability to do what you want to do. But instead of stopping there, it also requires that you have the ability to act differently than you actually did. That is why it is called “alternative possibilities,” because alternative possibilities are required to truly have free will. This is obviously incompatible with determinism because with this viewpoint more than one possible future and the ability to choose between them must always be possible when in determinism it is not.

     The third viewpoint is called the source view on freedom. This view on free will reasons that instead of looking towards our actions and what we could do, we should look at the relationship between the actions we perform and the forerunning sources that lead to them. This belief describes that for an action to be free it must be sourced from the person performing the action. This directly conflicts with determinism because if determinism is true no one is the ultimate source of their own actions. This is a crucial point to make but there is also an argument which theorizes that while we have no control over the ultimate source of our actions, we could be the source of our actions in the sense of moral responsibility. Put simply, under determinism we will never be the ultimate source of our own actions, but it can be argued that it does not dictate our ability to control how we conduct ourselves during these actions.

     All these theories provide crucial and thought-provoking views on free will and determinism, but how do they apply to Locke’s Voluntary Prisoner? Locke’s thought experiment questioned that when the man decided he preferred to stay, did that make his stay voluntary? To truly answer this question, one must look at all the ways in which free will can be interpreted. To begin we must view the question through the lenses of pure determinism. In accordance with this belief, there was only ever one physically possible future for the sleeping man. According to an account of the past events and the laws of nature, it is physically impossible for the man to leave the locked room meaning no matter how the man felt there was only ever one possible future, him staying. This then rules out the possibility of his stay being voluntary. Voluntary in this case, meaning his decision is backed by free will.

     In terms of the three viewpoints of freedom, they each require their own consideration. In terms of easy freedom, his stay is not voluntary. This is because while the man does have the ability to do what he wants, in this case to stay; it is not considered free will because the past events and the laws of nature are external hindrances that effected his ability to control the cause of his actions. It is also using this logic that we can rule out the possibility of free will from the perspective of the alternative possibilities' viewpoint. Free will is ruled out because as stated in the thought experiment the room is locked, and it is physically impossible for the man to get out. This means there are no alternate possibilities for the man to choose and no free will is possible to make his stay voluntary.

     The third and final view of freedom could potentially provide some evidence that instead of free will being ruled out entirely, the man might have had some small amount of control over his situation. This view, called the source view, focuses on the source of an action and what predates it rather than what could be possible at any given time. It has already been determined that one can never truly be the source of their own actions because every possible action has already been defined by past events and laws of nature. However, it can be reasoned that the man is still the source of the self-control he uses to dictate his attitude towards the situation. The man is happy inside the locked room. He is not anxious about being imprisoned or angry with his lack of opportunity to leave. This is because in accordance with his own conduct and examination of the circumstances he decides that he is content to stay, making him the source of his preference to stay. Unfortunately, the compelling counterpoint of this is that the source of his willingness to stay is the person he would be staying with. In the way the thought experiment is proposed, his contentment hinges on the desirable company present, so it is possible to consider this the true source of his willingness to stay. In addition, because he had no control over their presence in the room, any free will that might have supported the claim that his stay could be considered voluntary becomes hard to find.

     In conclusion, according to the previously stated reasoning, the man's stay cannot be considered voluntary. It is his lack of control in the situation and the inability to be the own cause of his actions that takes away all free action. This is of course only considering this problem in terms of determinism and the comparisons made between the deterministic criteria and the viewpoints of freedom.