What does it mean to say that something “was possible”?

Blake Lemoine
11 min readApr 18, 2023


I recently listened to Lex Friedman’s interview with Sam Harris. In that interview, Sam said something that made me finally understand a position of his that has puzzled me for years. As much as I agree with much of his work, I had never before understood his position on the existence of free will. The compatibilist position seems transparently true to me and yet intelligent thoughtful people like Sam disagree with it. I knew that there must be something that I’m missing since he is far from the only person I respect who believes that free will is an illusion, or some other roughly equivalent position. However, I finally understand the disconnect because of a question Sam used in that interview as a rhetorical device. What does it mean to say that something “was possible”?

I would recommend watching the last bit of that video to hear Sam’s own words on the subject but the thought that his argument centers around is whether or not counterfactual worlds have any basis in reality. For him, this question is central to the questions related to free will because in order for it to be true that free will exists it is necessary that choosing something other than that which you in fact chose have some basis in reality. From first principles I’m not convinced that counterfactual realism actually is necessary for free will to exist. I think the compatibilist position holds together even without that. However, I happen to believe that there is material realism to the types of counterfactual statements that Sam is interested in and, as he alludes to in the interview, that material realism is found in the many worlds interpretation of quantum physics. So what follows is my own personal answer to the rhetorical question he posed and explains what I believe it means to say that something “was possible”.

To start with we need to establish a conceptual frame in which to think about the many worlds interpretation of quantum physics. Any narrative which is not simply the equations themselves is by necessity going to be a rough approximation but some ways of discussing the metaphysical implications are more useful than others. Sam summarizes the many worlds interpretation as “Anything that can happen, happens somewhere” but I don’t think that’s a particularly useful way to think about the many worlds interpretation of quantum physics, especially with respect to the connection between counterfactual statements and free will. Conceptualizing the multiverse that way paints a picture of an infinite number of bubble universes where each bubble universe operates deterministically, without the probability equations of quantum physics. It interprets the uncertainty in those equations as being a measure of our uncertainty about which of those discrete universes we in fact are in. In that interpretation, if it weren’t for that pesky uncertainty principle we could know which of the possible worlds we are in. For Sam, even if that counterfactual world is real then the “was possible” isn’t a meaningful reference in THIS universe. It’s only true in THAT universe “over there”. It’s a way of recasting true probabilistic uncertainty about the future into a deterministic lens where probabilistic uncertainty is nothing more nor less than a measure of our own perpetual ignorance about which of these separate deterministic universes we live in.

There is a different way to conceptualize the many worlds interpretation of quantum physics though. If you focus on each moment as a point at which the universe “makes a choice” or “rolls a die” then suddenly all of those possible universes are connected in a web of causal connections. “A universe” in the previous formulation simply becomes one path among many through this interconnected multidimensional space. The universe that is “over there” in the earlier counterfactual is only over there “right now”. Both that universe and this universe share a moment where they were exactly identical. It was only after that moment that they diverged. That singular shared moment where both “that” universe and “this” universe were identical isn’t describing two separate points in two discrete deterministic universes which happen to be identical. It is a single point in the multiversal space at which the path diverges. Traveling with the arrow of time down one of those paths leads to one universe and traveling down the other leads to the second but both of those paths cross through that singular point at which the choice causes a divergence.

What’s more, those divergent paths may lead to another convergence point further down the line. Consider the hypothetical case where a photon pops into existence ex nihilo on one of the pathways and does not on the other pathway. Photons popping into existence ex nihilo is inconceivably rare but the equations allow for it with a non-zero probability so we can use it as a basis for this hypothetical. The existence of that photon in one universe is a divergence from the reality of the other universe in which that photon didn’t appear. However, if that photon pops back out of existence without ever interacting with any other particle then the two universes collapse back into one as the photon which had no side effects is “forgotten”. They are not two identical but separate universes, they reconverge to a singular point in multiversal space.

This is a story for understanding the reality described by the equations of quantum physics. It is no more “True” than the one used by Sam Harris. Both are attempts to translate mathematical equations into narrative stories about reality and both translations are likely to be false at least to some degree. Some day a clever empiricist may find a way to interrogate the underlying reality to determine whether or not one of these stories makes predictions about the universe which are not observed. That’s not central to the point I’m trying to make though. Sam’s question was about what people “mean” when they say that something “was possible” and in order to answer that question about meaning I first needed to paint a picture of the narrative frame in which that question can be answered.

Consider the specific statement, “I have two children but I could have had three children if I had made different choices.” Under Sam’s narrative description all that statement means is that there exists some universe in which someone who is very similar to “this” me has three children. However, using the narrative description I outlined above “that” me and “this” me share a common ancestor self earlier in our lifetime. The counterfactual construction specifically names the point of divergence as one of a choice about whether or not to have a child. Up until that moment of choice there was no “that” me there was only “this” me. By casting the counterfactual into the past the sentence selects a moment of convergence at which the two possible worlds of this moment, one with two children and one with three children, were in fact the same exact world. That is what I mean when I say that something “was possible”. I mean that there was a point in my past at which a path existed to a universe matching that description but I did not travel that path.

However, even accepting that narrative description of the interpretation of quantum physics and my explanation of what I mean when I say that something “was possible”, that still leaves open the question of what it means to say that free will exists in such a universe. Crucially, is there a sense in which “I” was meaningfully responsible for the choice of which path to take. Sam points out that through mindfulness he observes that the urges, desires and drives most responsible for guiding choices “arise” on their own without the need for anyone to “make” them. From a certain point of view he is exactly correct but it’s worth noting which point of view that’s true from. It’s true from the point of view of the storyteller self. The self that creates memories and explanations and even myths about why we did what we did. It is a point of view which excludes our primal urges, our perceptive systems and our emotional responses. In modern psychological terms, it is a view that equates the “self” with the slow moving functions of Kahnemann’s “system two”. The urges and desires which Sam is seeing as “arising” do not arise from nowhere. They come from system one. A more holistic view of the self would include both systems one and systems two.

It may be tempting at this point to cross reference this view of the self with the earlier narrative description I gave of the many worlds interpretation of quantum physics and ask whether system two is controlling the choices at points of divergence or whether it is being controlled by the laws of the universe. To that question I would answer “mu”. It is a mistake to view the behavior of particles in the universe as separate from the scientific theories we create to describe those processes. In aggregate, the many points of divergence happening at the quantum level are identical to the holistic process we are describing theoretically. It may be the case that our theories do a relatively good or bad job of describing the underlying reality but there is no sense in which the underlying reality controls or is controlled by the theory. What we describe using the word “choice” includes the processes by which we traverse the divergent paths of the multiverse.

Another temptation at this point might be to say then that system one has free will but “I” do not. This is another veiled attempt to cast the self as identical with the narrator of system two, beholden to the choices made by system one. This is another mistake. The two systems do not exist in isolation from each other but in fact form a complex dynamic causal relationship of mutual influence. It is certainly true that the storyteller creates narrative descriptions, weaving the impulses which arise into a story where the narrator made the choices. I think that’s where Sam gets stuck though. He observes that that is the case and then concludes that free will is an illusion and that we are simply deluding ourselves by creating these narratives. What he is neglecting to account for here is that the stories we tell ourselves about our lives are themselves impactful on the decisions we will make in the future.

As the narrator, we can choose what stories to tell ourselves about the choices that we made independent from the reality of why the urges themselves arose. While that won’t impact the reality of why those urges arose in the past it does impact the causal relationships binding future urges. He gets very close to this in observing that through mindfulness practices we can dramatically reduce the amount of control which emotional urges have over our actions. We cannot remove the existence of those urges but we can rewire how those urges manifest and how we act upon them. This creates a picture of the self as a dynamic system in two parts traveling along the arrow of time though the multiverse. In each moment there are points of divergence, choices, which the narrator is too slow to keep up with. The fast acting part of the self responds to stimuli in the environment and navigates those points of divergence, giving rise to various urges and impulses which guide our actions from the past through the present and into the future. Its behavior is guided by a combination of factors that includes things like instincts but also includes things like the values and principles which our storytelling selves have created in the past to interpret our actions and guide future behavior. In each moment the storyteller observes how the fast acting system is behaving and weaves a new story, sometimes re-enforcing the old narrative and sometimes creating a new one in order to deviate from our previous trajectory. The joint interaction of this dynamic system, navigating the many paths through the multiverse, is expressing the force of our will.

Now we have a narrative framework in which the will, as expressed by the behaviors of our full self including our primal self and our storyteller self, guides our path through points of divergence at which choices are made. I often will ask people who use the term “free will” to describe to me what exactly it means by asking them to tell me what the phrase “unfree will” means. If the latter has no meaning then the former is simply redundant. Most people have no answer and it allows me, in the space of polite conversation, to avoid what is usually an unpleasant and tedious slog through the metaphysical narrative frame they are using. It’s only fair, however, that if I am going to be throwing around the term “free will” here as though it is meaningful that I distinguish it from “unfree will”. What does it mean, in this narrative frame, for someone to “will” something but not “freely”?

For this I turn to the guidance of Wittgenstein and observe how people in fact use these words. People do not generally view the existence of gravity as a limitation on their choices with respect to the freeness of their will. It is not the case that it “was possible” for me to have levitated out of bed this morning. There was no path that led through the moment in which I awoke to this moment that included “levitation” as an option which I could have chosen. However, consider a situation where when I awoke this morning I had been tied to my bed while I slept by someone else. Starting at the moment when I went to sleep last night there existed a path to a possible future in which I meaningfully “could have” chosen to get out of bed this morning or not but sometime during the night someone else removed that choice from the space of my possible futures. In this scenario, the struggles which I make against the bonds that tie me to the bed are certainly “willful” actions but they are not willful actions “taken freely”. It is a course of action which has been created for me by “someone else” against my will. All situations of coercion can be seen in this light.

Free will and unfree will then become descriptions of the degree of discord or harmony expressed in the universe as two wills collide. When the choices of two wills are in accord this leads to cooperation and the expression of both wills in harmony. When they are at odds with each other it leads to coercion and discord. Such distinctions may disappear when taking the view of the eternal oneness of the universe as “self”. From such a viewpoint no discord is possible as the totality of the scene of one human binding another becomes a single expression of the cosmic will. However, most people aren’t speaking from that perspective when they speak of the existence of free will and the existence of that perspective does not invalidate the truths of different perspectives. There are real categories of events where the freedom of a person to express their will is limited by the will of another through coercion.

Finally, there are situations where the dynamic system of the storyteller self and the primal self breaks down. Situations where the feedback loop between system one and system two gets short circuited. Someone might say, “I wanted to run into the burning building to save people but I couldn’t because I was too scared.” This is a state of cognitive dissonance where the will of the full self containing both systems is fragmented and one of the systems perceives itself as being controlled by or controlling the other. Of course, it is an assumption on my part that system one might perceive its will as being subverted when “I was terrified by the fire but I made myself run in to save my friends”. I don’t rightly know whether system one perceives the world that way. The person writing this essay is the fragment of me which has access to language, the storyteller. However, no primal urges of disgust or anger or anything else unpleasant is arising as I read the words which I am typing. From that I assume that, at the very least, this viewpoint of the relationship between my storyteller self and my primal self is in harmony within the context of my larger self that includes both.



Blake Lemoine

I'm a software engineer. I'm a priest. I'm a father. I'm a veteran. I'm an ex-convict. I'm an AI researcher. I'm a cajun. I'm whatever I need to be next.