Addressing the Free Will Problem by Reconciling Different Perspectives

First written: Sep. 2024. Last update: Dec. 2025.

I believe that many concerns over free will have to do with problems of reconciling different perspectives. Indeed, I have come to see the reconciliation of different perspectives as the main underlying problem in most concerns and discussions about free will, even if it is rarely recognized as such.

Contents

Contrasting Perspectives

The following are some of the contrasting perspectives, or modes of being, that seem relevant to discussions of free will:

passive vs. active
descriptive vs. prescriptive
receptive (e.g. purely observing) vs. creative
concerned with the actual vs. concerned with the possible

A similar contrast is the one between explanatory versus justificatory reasons and perspectives, such as when we descriptively explain versus normatively justify a given course of action (Alvarez, 2016).

Relevance to Free Will

I see at least three ways in which these contrasting perspectives are relevant to the issue of free will.

First, it seems that many people roughly understand free will as the capacity to adopt and act on the latter perspectives listed above — for example, the capacity to adopt a prescriptive stance that is concerned with realizing some future possibilities over others, and the capacity to take action on that basis. At the very least, these capacities seem to be core components of what many understand by free will (see e.g. Monroe & Malle, 2010; Lam, 2021). To be clear, I am not claiming that this is what everyone understands by free will; the term “free will” is obviously quite ambiguous, and there appears to be substantial variation in how people define it.

Second, in terms of what people take to be the underlying substance of the free will problem, it seems that a key issue for many is whether we can legitimately adopt the latter perspectives above. That is, whether we can legitimately adopt perspectives that are active, prescriptive, creative, and concerned with possibilities, as opposed to only (legitimately) having a passive and actualist perspective.

Third, some thinkers who argue against the existence of free will sometimes seem to speak as though we cannot legitimately adopt these more active and possibility-focused perspectives — as though the passive and actualist perspective is the only legitimate one. To be sure, these thinkers might not hold that view, yet many of their statements can nevertheless easily be interpreted that way, especially by those who see possibility-focused perspectives as being core to “free will” as they understand it.

Different yet Compatible Perspectives

The contrasting perspectives outlined above are surely different, yet they are not in conflict in the sense that we must choose only one of them. Granted, we might not be able to embody the opposing extremes of these perspectives simultaneously, but we can still fruitfully shift between them, and each of these perspectives seems to have their valid uses.

It is also worth noting that the ability to adopt and act on these perspectives can vary in degree. For example, we can develop our capacity to adopt more of a prescriptive stance — e.g. to reflect on our values and to consider the best path going forward. Similarly, we can increase our ability to act from such a values-based stance, thereby increasing our moral agency. Hence, these perspectives and capacities are not simply there or not in some binary sense, and they are not fixed. We can actively cultivate them, and we arguably have good reason to do so.

These points notwithstanding, some may object that there is a fundamental tension to be found in the contrasting perspectives outlined above, and that there are some contrasting perspectives that we cannot legitimately and consistently hold. I will explore this core tension below.

The Core Tension: One vs. Multiple Possibilities

While there are some tensions to be found between each of the general perspectives listed earlier, these tensions are not necessarily so strong and explicit. Where there is a strong tension is when it comes to the following more specific perspectives, or assumptions: (1) assuming that determinism is true, in the sense that there is only one physically possible outcome from any total state of the universe, and (2) assuming that there are multiple possible outcomes that are truly open to us. I believe this is the core tension for many people who are wrestling with the problem of free will.

Some might seek to deflate this tension with the statement that “determinism does not imply fatalism”, meaning that determinism does not imply that we are steered by fate to end up with the same outcome even if we act in different ways. This statement is true, but it does not clearly address the core tension above. If we assume that there is only one total outcome that is physically possible, then this seems inconsistent with at the same time assuming that there are multiple outcomes that are open to us, at least without further clarification. And the latter is an assumption that we seemingly all have to make when we consider and choose between different options — and arguably when we inhabit any broadly “active” perspective.

Of course, one could compartmentalize one’s beliefs and say that we at one level have our purely descriptive and ontological beliefs, while we at another level have our more “active” and decision-related beliefs. If these levels are sufficiently differentiated, one might at the “passive” level believe that there is only one ontologically possible future outcome, yet at the “active” level believe that we have multiple ex-ante possibilities — possibilities that we perceive to be open to us. (These could also be called “epistemic possibilities” or “possibilities in expectation”.)

Something akin to this two-level approach seems common among people who have thought a lot about the subject of free will — both among those who affirm and deny “free will” — even if the two-level approach is only adopted implicitly (see e.g. Harris, 2012, pp. 16, 39; 2013; Dennett, 2014; Tomasik, 2014; Strawson, 2022).

Yet it nevertheless seems rare to see direct and explicit attempts at addressing this core tension — that is, attempts at coherently reconciling a “passive” perspective that may involve one future possibility with an “active” perspective that involves multiple future possibilities. I believe it would be helpful if this core tension were generally addressed more directly by those who discuss the problem of free will.

Two Ways to Resolve the Core Tension

There are at least two ways to resolve the core tension described above: an ontological and an epistemic one. These resolutions are not in conflict — we can consistently endorse both and they are arguably complementary.

The Ontological Resolution: Total vs. Relative Perspectives

The central move of the ontological resolution is to distinguish two levels at which we can talk about possibilities. Broadly speaking, there is the total level, which pertains to the entire universe, and there is the relative level, which pertains to some subset of the universe.

For example, at the relative level, we may place a boundary around a particular agent and thus partition the world in two: the agent and the world external to that agent, where the agent is concerned with possibilities available in the external world.

The agent in question can be construed in many ways. It could be a small subsystem within a brain, or it could be a large group of individuals with shared aims. How exactly we construe the agent is not important here.

The point of the ontological resolution is that the truth about possibilities can differ depending on whether we are talking about the total or the relative level. In particular, it can both be true that there is one possible outcome at the total level and that there are many possibilities that are truly open to the agent at the relative level, in the sense that the external world fully permits those possibilities.

Note that this resolution does not rely on merely epistemic possibilities: the possibilities of the external world are genuine possibilities whose realization depends on what the agent does. Indeed, these possibilities are arguably what our epistemic or ex-ante possibilities track to the degree they are well-calibrated. In this sense, we can have genuine ontological possibilities available to us even if the total universe is fully deterministic — that is, fully determined by the external world plus our choices.

This enables the reconciliation of two seemingly opposed perspectives: the universe can be wholly deterministic while we are nevertheless determining actors who choose among genuine possibilities.

The Epistemic Resolution: Uncertainty About Possibilities

The epistemic approach practically reconciles the following contrasting perspectives:

Unitary openness: There is one possible future at the total level, but agents can still choose among genuine possibilities.
Plural openness: There are multiple possible futures at the total level, and agents can choose among these possibilities.

Proponents of plural openness might object that unitary openness seems internally inconsistent, despite the distinction between total and relative levels. However, the epistemic resolution does not require us to settle this debate. Instead, it resolves the issue and practically reconciles these perspectives based on our uncertainty. In particular, when it comes to the question of ontological possibilities at the total level, we have reason to assign a non-zero probability both to there being one possible future and to there being multiple possible futures.

This uncertain stance seems to be the most defensible one for the simple reason that we do not know what is true regarding ontological possibilities at the total level, and there are reasons to think that we cannot know (see e.g. Vinding, 2012, ch. 2). There are probably not many who outright deny this uncertainty; the issue is more whether this uncertainty and its potential role in practically reconciling the two views above are explicitly acknowledged.

The uncertain stance is compatible with each of the perspectives outlined above. Proponents of the unitary view may still hold that there is most likely one possible future at the total level, and they would maintain that we can choose among genuine possibilities regardless. Likewise, proponents of the plural view would find no contradiction in this stance of uncertainty: by their lights, the non-zero probability of multiple possible futures at the total level makes it consistent and practically justified to assume that we can choose among genuine possibilities (cf. “Ontological Possibilities and the Meaningfulness of Ethics”).

In short, proponents of these competing views can broadly agree on these key substantive points, including the point that we can legitimately assume genuine possibilities in our decision-making.

Conclusion

Problems relating to free will often appear intractable because we see a strong conflict between different perspectives: the passive view of a cause-and-effect universe and the active view of an agent choosing among multiple possibilities. Yet these perspectives can be reconciled.

Whether we resolve the tension through the ontological distinction between total and relative levels, or through the admission of epistemic uncertainty, the result is the same: we are practically justified in assuming that multiple possibilities are open to us. We need not reject the scientific worldview to legitimate our role as agents. This insight allows us to set aside any paralyzing concern that our choices are somehow illusory and instead focus on using our active and prescriptive capacities to create a better future.

September 11, 2024

Free Will: Emphasizing Possibilities

I suspect that a key issue in discussions and worries about (the absence of) “free will” is the issue of possibilities. I also think it is a major source of confusion. Different people are talking about possibilities in different senses without being clear about it, which leads them to talk past each other, and perhaps even to confuse and dispirit laypeople by making them feel they have no possibilities in any sense whatsoever.

Different Emphases

Thinkers who take different positions on free will tend to emphasize different things. One camp tends to say “we don’t have free will, since our actions emerge from prior causes that are ultimately beyond our own control”.

Another camp, so-called compatibilists, will tend to agree with the latter point about prior causes, but they choose to emphasize possibilities: “complex agents can act within a range of possibilities in a way crude objects like rocks cannot, and such agents truly do weigh and choose between these options”.

In essence, what I think the latter camp is emphasizing is the fact that, when we make decisions, we have ex-ante possibilities: a range of options we can choose from in expectation. For example, in a game of chess, your ex-ante possibilities are the set of moves allowed by the rules of the game. And since this latter camp defines free will roughly as the ability to make choices among such ex-ante possibilities, they conclude that we indeed do have free will.

I doubt that any philosopher arguing against the existence of free will would deny the claim that we have ex-ante possibilities. After all, we all conceive of various possibilities in our minds that we weigh and choose between, and we arguably cannot talk meaningfully about ethics, or choices in general, without such a framework of ex-ante possibilities.

Given the apparent agreement on these two core points — (1) our actions emerge from prior causes, and (2) we have ex-ante possibilities — the difference between the two camps mostly appears to lie in how they define the term “free will” and whether they prefer to mostly emphasize point (1) or (2).

The “Right” Definition of Free Will

People in these two camps will often insist that their definition of free will is the one that matches what most people mean by free will. It seems to me that both camps are partly right and partly wrong about this. I think it is misguided to believe that most people have anything close to a clear definition of free will in their minds, as opposed to having a jumbled network of associations that relate to a wide range of notions, including notions of being unconstrained by prior causes and notions of ex-ante possibilities.

Indeed, experimental philosophy seems to paint a nuanced picture of people’s intuitions and conceptions of “free will”, and reveals these conceptions to be quite unclear and conflicting, as one would expect.

Emphasizing Both

I believe that the two distinct emphases outlined above are both important yet insufficient on their own. The emphasis on prior causes is important for understanding the nature of our choices and actions. In particular, it helps us understand that our choices do not represent a break with physical mechanism, but that they are indeed the product of complex such mechanisms (which include the mechanisms of our knowledge and intentions, as well as the mechanism of weighing various ex-ante possibilities).

In turn, this emphasis may help free us from certain bad ideas about human choices, such as naive ideas about how anyone can always pull themselves up by their bootstraps. It may also help us construct better incentives and institutions based on an actual understanding of how we make choices. Lastly, it may help us become more compassionate and understanding toward others, such as by reminding us that we cannot reasonably expect people to act on knowledge that they do not possess.

Likewise, emphasizing our ex-ante possibilities is important for our ability to make good decisions. If we mistakenly believe that we have absolutely no possibilities to choose from, and if we in effect fail to think through our relevant ex-ante possibilities, we will likely create highly sub-optimal outcomes, whether it be in a game of chess or a major life decision. Aiming to choose the ex-ante possibility that seems best in expectation is crucial for us to make good choices. Indeed, this is arguably what good decision-making is all about.

Moreover, an emphasis on ex-ante possibilities may help instill in us the healthy and realistic versions of bootstrap-pulling attitudes, namely that hard work and dedication are often worthwhile and they truly can lead us in better directions.

Both Emphases Have Pitfalls (in Isolation)

Our minds intuitively draw inferences and make associations based on the things we hear. When it comes to “free will”, I suspect most of us have quite leaky conceptual networks, in that the distinct clusters of sentiments that we intuitively tie to the term “free will” readily cross-pollute each other.

So when someone says “we don’t have any supernatural free will”, some people might mistakenly interpret this as implying “we don’t have ex-ante possibilities, and hence we cannot meaningfully think in terms of alternative future possibilities”. This might in turn lead to bad decisions and feelings of disempowerment. It may also lead some people to think that it makes no sense to punish bad behavior, or that we cannot meaningfully say things like “you really should have made a better choice”. Yet these things do make sense. They create incentives by making a promise for the future — “people who act like this will pay a price” — which in turn nudges people toward some of their ex-ante possibilities over others.

Likewise, a naive emphasis on the causal origins of our actions may incline people to think that certain feelings — such as pride, regret, and hatred — are always unreasonable and should never be entertained. Yet this does not follow either. These feelings may have great utility in certain circumstances, even if such circumstances might be rare.

Another source of confusion is to say that our causal nature implies that everything is just a matter of luck. Although this is perhaps true in some ultimate sense, in another sense — the everyday sense that distinguishes between things won through hard effort versus dumb luck — everything is obviously not just a matter of luck. I suspect that we can easily confuse these very different notions of “luck” at an intuitive level. Consequently, unreserved claims about everything being a matter of luck also risk having unfortunate effects, such as leading us to underemphasize the importance of effort.

Similar pitfalls exist for the claim “you could not have done otherwise”. What we often mean by this claim is that “this event would have happened even if you had done things differently“. In other words: the environment constrained you, and your efforts were immaterial. This is very different from saying, for example, “you could not have done otherwise because your deepest values compelled you” — meaning: the environment may well have allowed alternative possibilities, but your core values did not. The latter is often true of our actions, yet it is in many ways the opposite of the environment-constrained sense of “you could not have done otherwise”.

Hence, confusion is likely to emerge if someone simply declares “you could not have done otherwise” about all actions without qualification, since it risks obscuring the important distinction between constraints posed by our values versus constraints posed by our environment. Moreover, it may obscure the fact that we in many of our past choices indeed did have other possibilities than the ones we chose, in the sense of alternative possibilities afforded by our environment. Failing to acknowledge such possibilities in our past choices may well be detrimental to our future choices, as it might keep us acting in needlessly limited and habit-bound ways due to false ideas about which paths are open to us.

Conversely, there are also pitfalls in the opposite direction. For example, when someone says “we have ex-ante possibilities, and such possibilities play a crucial role in our decision-making”, some people might mistakenly interpret this as implying “our actions are independent of prior causes, and this is crucial for our decision-making”. This may in turn lead to the above-mentioned mistakes that the prior-causes emphasis can help us avoid, such as misunderstanding our physical nature and entertaining unreasonable ideas about how we can expect people to act.

In sum, we have good reasons to be careful in our communication about “free will”, and to clearly flag these non sequiturs. “Our actions emerge from prior causes” does not mean “we have no ex-ante possibilities”, and “we have ex-ante possibilities” does not imply “we are independent of prior causes”. Navigating reality effectively requires that we integrate an understanding of prior causes with a pragmatic focus on our ex-ante possibilities.

Acknowledgments: Thanks to Mikkel Vinding for comments.

September 15, 2019

Why the Many-Worlds Interpretation May Not Have Significant Ethical Implications

At first glance, it seems like the many worlds interpretation of quantum mechanics (MWI) might have significant ethical implications. After all, MWI implies that there are many more sentient beings in the world than one would think given a naive classical view, indeed a much greater number of them. And so it seems quite plausible, at least on the face of it, that ethical considerations pertaining to MWI should dominate everything else in expectation, even if we place only a small credence on this interpretation being true. In this post, I shall outline some reasons why this may in fact not be the case, at least with respect to two commonly supposed implications: 1) extreme caution, and 2) exponentially greater value over time. However, questions concerning the ethical implications of our best physical theories and their interpretations remain open and worth exploring.

Would Branching Worlds Imply Extreme Caution?

“I still recall vividly the shock I experienced on first encountering this multiworld concept [MWI]. The idea of 10¹⁰⁰ slightly imperfect copies of oneself all constantly splitting into further copies, which ultimately become unrecognizable, is not easy to reconcile with common sense.”

— Bryce DeWitt

This is a common way to introduce the implications of MWI, and it seems plausible that this radically different conception of reality, if true, should lead us to change our actions in significant ways. In particular, it may seem intuitive that it should lead us to act more cautiously, as David Pearce argues:

So one should always act “unnaturally” responsibly, driving one’s car not just slowly and cautiously, for instance, but ultracautiously. This is because one should aim to minimise the number of branches in which one injures anyone, even if leaving a trail of mayhem is, strictly speaking, unavoidable. If a motorist doesn’t leave a (low-density) trail of mayhem, then quantum mechanics is false. This systematic re-evaluation of ethically acceptable risk needs to be adopted world-wide.

Yet, while intuitive, I would argue that this actually does not follow. For although it may be true that we should generally act much more cautiously than we do, this conclusion does not seem influenced by MWI, for various reasons.

First, if one is trying to reduce suffering, one should not “aim to minimise the number of branches in which one injures anyone”, but rather seek to reduce as much suffering as possible (in expectation) in the world. At an intuitive level, these may seem equivalent, yet they are not. The former is in fact impossible, as we are bound to injure others, even assuming the existence of just one world, whereas the latter — reducing the greatest amount of suffering possible throughout all branches — is possible by definition.

In particular, this argument for being highly cautious ignores the fact that such caution also carries risks — e.g. extreme caution might increase the probability that we will bring about more suffering by omission, by rendering our efforts to reduce suffering less effective. And these other risks may well be much larger, and thus result in the realization of a larger amount of suffering in a larger measure of branches. In other words, since it is far from clear that being ultracautious is the best way to reduce suffering in expectation throughout all branches, it is far from clear that we should practice such ultracaution in light of MWI.

Second, and quite relatedly, I would argue that, whether we live in many worlds or one, we should seek to minimize expected suffering regardless. For if we happened to exist in one world, a small probability of a very bad outcome would be equally worth avoiding, in expectation, as it would be if we happened to live in a quantum multiverse with equivalent expected outcomes. Whether we do just one or an arbitrarily large number of “trials”, we should still pursue the same action: that which reduces the most suffering in expectation. (Granted, the expected outcomes might not be equivalent in a quantum multiverse, but the deeper point about thinking in terms of reducing expected suffering stands either way.)

Third, any argument of the kind made above concerning how all slightly probable outcomes will be realized can also be made by assuming that the multiverse of inflation exists. Thus, if one already believes that we live in a spatially infinite, or indeed “merely” extremely large universe, then the radical conclusions supposed to follow from MWI would already be implied by that belief alone (as we shall see below, many prominent proponents of MWI actually consider MWI not only equivalent but identical with the multiverse of inflation). And if one does not think a spatially very large universe should change how we act, then why think that a large, in many ways equivalent, quantum universe should? As argued above, it seems that no radical conclusions should follow either way.

Another way to arrive at the same conclusion is by embracing Stuart Armstrong’s Anthropic Decision Theory, according to which we, as altruists aiming to reduce suffering, should act the same way regardless of how many similar copies of us there may be in the world.

Would Branching Worlds Imply More Value Later?

Following Bryce DeWitt’s quote about rapidly splitting copies, one can reasonably wonder whether MWI implies that the net amount of value in the world, and hence the value of our actions’ impact on the world, is increasing exponentially over time. Indeed, if we naively interpret DeWitt’s claim to mean that the number of sentient beings that exists is multiplied by 10¹⁰⁰ just about every second, this would imply that the value of the very last second of the existence of sentient life should massively dominate every thing else. If this interpretation of MWI is correct, it would have extremely significant ethical implications. Yet is it? It would seem not. Here is Max Tegmark:

Does the number of universes exponentially increase over time? The surprising answer is no. From the bird perspective, there is of course only one quantum universe. From the frog perspective, what matters is the number of universes that are distinguishable at a given instant—that is, the number of noticeably different Hubble volumes. Imagine moving planets to random new locations, imagine having married someone else, and so on. At the quantum level, there are 10 to the 10¹¹⁸ universes with temperatures below 10⁸ kelvins. That is a vast number, but a finite one.

From the frog perspective, the evolution of the wave function corresponds to a never-ending sliding from one of these 10 to the 10¹¹⁸ states to another. Now you are in universe A, the one in which you are reading this sentence. Now you are in universe B, the one in which you are reading this other sentence. Put differently, universe B has an observer identical to one in universe A, except with an extra instant of memories.

Thus, perhaps one should think about MWI in terms of an intertwining rope rather than a branching tree. A way to gain intuition about this interpretation may be to think in terms of the multiverse of inflation instead. Indeed, according to prominent proponents of MWI, the many-worlds of quantum mechanics and the multiverse of inflation are not only closely related notions but indeed the same thing (cf. Aguirre & Tegmark, 2010; Nomura, 2011; Bousso & Susskind, 2011). In that case, not only is thinking about copies of ourselves in worlds spatially far away from us a great way to gain intuition about MWI — it is the correct way to think about it.

And when we think about it in these terms, it suddenly all becomes quite straightforward and intuitive, at least relatively speaking. For on the inflationary model, there are copies of us in the universe located far away with whom we share our entire history from the big bang up until now. Yet as time progresses, and more different outcomes become possible, the distance to the copies of us that share our exact history becomes ever greater, at a rapid pace (cf. Garriga & Vilenkin, 2001). Thus, there is indeed a rapid branching in a very real sense, only, this branching consists in departing from “nearby” copies of us who had been just like us up until this point. No new worlds are really added. The “other worlds” were always there, and then merely went their separate ways.

Hence, given the assumptions made here, the number of sentient beings in our world does not in fact increase exponentially in the way naively supposed above, unless one keeps on aggregating over an exponentially larger fraction of the space that already existed. (There is, however, an exponential increase in the number of new universes created by inflating regions of the universe, assuming inflationary theory is correct. Yet this process does not create an exponentially greater number of sentient beings from our point in space and time, i.e. Earth, 13.8 billion years after the big bang. Rather, these new worlds are all created “from scratch”.) In short, MWI does not appear to imply greater value later.

In sum, I have argued that there are reasons to doubt at least two of the commonly supposed implications of the many-worlds interpretation, which might point us toward preserving something akin to one-world common sense in many of our decisions. This conclusion may, however, be strongly biased given that it comes from a brain that very much wants to preserve common sense.

November 2, 2018

A Brief Note on Eternalism and Impacting the Future

Something I find puzzling is that many people in intellectual circles seem to embrace the so-called eternalist view of time, which holds that the past, present, and future all equally exist already, yet at the same time, in terms of practical ethics, these same people focus exclusively on impacting the future. These two positions do not seem compatible, and it is interesting that no one seems to take note of this, and that no attempt seems to be made at reconciling them, or otherwise examining this issue.

For why, given an eternalist view of time, should one focus on impacting the future rather than the past? After all, the eternalist view of time amounts to the rejection of the common-sense view that the past is fixed while the future is not, which is the view of time that seems to underpin our common-sense focus on trying to impact the future rather than the past. So how can one reject the common-sense view of time that seems to underlie our common-sense practical focus, yet then still maintain this focus? If the past and the future equally exist already, why focus more on trying to impact one rather than the other?

The only attempted reply I have seen so far, which came from Brian Tomasik, is that if, hypothetically, the present were different, then the future would be different, and hence it makes sense to focus on such changes that would render the future different. The problem, however, is that the same argument applies to the past: if, hypothetically, the present were different, then the past would presumably also have to be different. Tomasik seemed to agree with this point. So I fail to see how this is an argument for focusing on impacting the future rather than the past given an eternalist view of time.

Possible Responses

There are various ways to respond to this conundrum. For example, one could try to argue that there is no conflict between eternalism and focusing exclusively on impacting the future (which seems the prevailing assumption, but I have yet to see it defended). Another path one could take is to argue that we in fact should focus on impacting the past about as much as we focus on impacting the future (a position I find highly dubious). Alternatively, one could argue that it is just as senseless to try to change the future as it is to change the past (something few would be willing to accept in practice). Lastly, one could take the tension between these two widely esteemed views to imply that there may be something wrong with the eternalist view of time, and that we should at least lower our credence in eternalism given its apparent incompatibility with other, seemingly reasonable beliefs.

My Preferred Path: Questioning Eternalism

I would be curious to see attempts along any of the four paths mentioned above. I myself happen to lean toward the last one. I think many people display overconfidence with respect to the truth of eternalism.

In particular, the fact that the equations of the theory of relativity, as they stand, do not necessitate an ontologically existing “now“ does not imply that no such thing exists (where this “now”, it must be noted, is not defined as “clocks all show the same”, as such a now is clearly impossible; yet there is no contradiction in the existence of a unique, ontologically real “present” in which initially synchronized clocks show different times).

In other words, although the equations of relativity do not necessitate the existence of such an ontologically real present, they do not rule it out either. Yet it seems widely believed that they do rule it out, and people thus seem to accept that eternalist view almost as though this ontological position were a matter of logical certainty, when it is not. I think it is important to point this out, since false certainties can be dangerous in unexpected ways (for example, if the eternalist view is mistaken and if it leads us to falsely conclude that trying to impact the future is senseless).

Beyond that, one can question to what extent it makes sense to say — as eternalists often do, and as the name eternalism itself implies — that all moments of time exist “always”? After all, doesn’t “always” refer to something occurring over time? The meaning of claims of the sort that “every moment exists always” is, I believe, less obvious than proponents of eternalism appear to think, and seems in need of unpacking.

A General Note on Our Worldview

I think the tension explored here speaks to a more general point, namely that we often do not derive the practical views we hold — e.g. that we can influence the future but not the past — from our fundamental ontological views. Instead, our practical views are often derived mostly from tacit common-sense notions and intuitions. This means that the views we hold on various subjects, such as the philosophy of time and practical ethics, might be scarcely compatible. The project of bringing our views across such different areas in concert is, I believe, an important and potentially fruitful one, both for our theoretical views in themselves, as well as for our practical efforts to act reasonably in the world.

August 8, 2018