It is probably reasonable to assume that no one reading this post has killed someone. Yet, at some level your response to the need has already been decided in your brain. You may have a moral sense that it is wrong, you may rationalize it for self-defense, you may assess its necessity, but at some level everyone has a "choice" already made regarding their possible responses to such a decision.
It may turn out that the choice is inadequate or incorrect, but neverthless it has already been formulated. With additional training (such as military, martial arts, or law enforcement), it may be modified and additional options created.
In short, the choice that we have formed is a function of all of our indoctrination, training, and brain physiology and, in effect, enables us to give ourselves "permission" to engage in a particular action.
Once we are presented with a particular situation, we will recall those choices and make a determination on which is the most appropriate (given our level of training) and act accordingly. As was already mentioned, this doesn't mean that the decision is necessarily appropriate or correct, but it will certainly be in line with what has been reasoned through previously. In the absence of any established knowledge or training, it would appear that the default state of the brain choices are divided between "fight, flight, or freeze".
This can be illustrated by the prospect of learning to play a musical instrument. While there may be some training necessary to acquire the appropriate muscle controls and coordination, the essential part of learning to play an instrument is to acquire a sufficient level of training so that choices are more readily available. Without any training, the individual brain is literally overwhelmed by the possibilities and suffers a kind of "paralysis" where the person literally has no idea of what to do next. Training mitigates such indecision and provides some guidelines and a framework against which the musician can decide what comes next.
The more extensive the training, the more the resultant behavior becomes almost instinctive and requires less conscious thought regarding the decisions made. As a result we have a deterministic system that is capable of utilizing a range of "choices" from which to draw decisions.
One of the key elements in formulating choices is that in determining the viability of particular scenarios, we effectively set a particular course of action that will be followed. If there has been little or no thought to a particular choice, even though we may be aware of the possibilities, the articulation of a choice may be incomplete or "malformed". This is typically seen has hesitation or an uncommitted (half-hearted) response.
Many instances of agonizing over decisions is actually based on rationalizing how we can do what we have already chosen to do anyway. In criminal matters, premeditation points to the time of formulating a choice before the act occurs. We even use the phrase "making up our minds" for when we've mentally resolved a decision before we act. These particular processes all highlight the underlying process that is occurring all the time. The brain's steady accumulation of data is such, so that as much information as possible is available to provide choices for when we need to make decisions.
This offers an explanation of why we can have responsibility for choices, but not display free will. This is especially true when one sees that therapy or modifying behaviors invariably requires additional education or knowledge so that the individual learns alternatives to their existing set of choices, and can redirect their possible actions down alternate paths.
What appears confusing when considering choices is that this action implies "freedom of choice" and by extension "free will", so how can this be reconciled to the idea that there is no free will?
If we consider any decision, it is obvious that it must relate back to a predetermined choice, which relates back to our indoctrination, emotions, training, etc. which relates back to the relationships established in our brain between data points, which ultimately relates back to our brain physiology. Each step is completely deterministic in terms of its operation.
Therefore to establish that there is no real "free will" we can consider changing the terminology slightly and examining the results. Instead of "free will", let's consider it "independent will". We can immediately see that the question that gets raised is "independent of what"? It cannot be independent since we've established a dependency during every step of acquiring the choices. So we must conclude that our "will" is equally dependent on being expressed solely within the terms of the choices that we've accumulated.
The critical distinction is that until we commit a choice with a decision and translate it into an action, it is merely an expression of our imagination. Our imagination is not an act of will and regardless of how flexible we consider our thoughts to be, it is only when they get translated into actions that we can determine how much freedom or independence of will actually exists. Since each step in the process to making a decision is seen to be deterministic, then our exercise of will to formulate a decision is equally deterministic. It cannot be otherwise.
In many cases we may have a multitude of basically trivial choices we can make, so it seems that we are exercising a significant amount of freedom, but even in this case, it is predetermined. As a thought experiment, consider making three choices regarding what you would like for dinner. After each, consider why you would like them tonight. In all likelihood you will be able to articulate a reason for your choice, so that there is never an item on your list where you would be puzzled and question why it was there. So, once again, we can conclude that our choices are purely deterministic, since each has a cause and therefore cannot be considered as "independent" in any way. Similarly, if you were to conduct this experiment at another time, you would likely list different items, but once again, each would have a reason for being on your list. As many times as you might repeat this exercise, there will never be an instance of where an item appears on the list without a cause or reason. Therefore we can assert that there is no possibility of a meal being added to the list that is independent or free of predetermined causes.
Even if you decided to sabotage the thought experiment by listing a food that you don't like, there would still be a predetermined reason for that item being listed, namely your intention to sabotage the experiment.
The only freedom or independence that can be left for consideration is the decision to remove a choice as an action option. Once again, this would involve a cause and effect situation since there must be a cause in order to engage in such a decision. The alcoholic that elects to never drink again, removes drinking as a choice for future actions. The individual that wants to lose weight may elect to remove high calorie foods from their diet. The individual that eliminates an option because it is deemed evil. In all these cases, we are modifying the choices that we will consider for decisions, but, once again, we are not operating independently in the formulation of such a move, but rather we are acting on a different cause to rearrange the options available for us to choose from.
From this we can see that every decision is based on a completely deterministic process from which we can elect to act on various choices. Sometimes to a greater or lesser extent, but each is completely determined. It is because of this ability to "manage" our options that we can derive the basis for moral responsibility, which will be considered in the next article.