“If you don’t surrender, we’ll start shooting!” police negotiators warn the robbers hiding inside the bank. The threat may be effective because the criminals can easily imagine a scenario in which they’re killed by police gunfire. If they choose to surrender and end up in prison, they’ll likely find themselves asking “what if,” wondering whether there might have been another way out.
“What would have happened if…?” is a question that crosses our minds quite often – even when we’re not planning a bank robbery. This kind of reasoning – “if X, then Y” – is known in philosophy as a conditional. Among conditionals, some we intuitively take to be true (“If I go to the seaside, I’ll be able to swim”), while others we tend to regard as false (“If I go to the seaside, I’ll be able to ski”). But sentences like “If I had been there with you, everything would have turned out differently…” or “If I hadn’t done that, I’d be a different person now” are examples of so-called counterfactuals – and those are much trickier.
The difficulty with counterfactuals is that we don’t really know what makes them true or false. What does it mean to say, “If something hadn’t happened, something else would have”? How can we know what would have happened if it didn’t? Why do our intuitions favor some answers over others – and how can we even talk about truth or falsity in situations that never actually occurred? These questions might seem like abstract philosophical puzzles. In reality, though, counterfactual thinking plays a central role in how our minds work – from how we experience emotions to how we develop advanced science.
Counterfactual reasoning is what makes us feel disappointed when things don’t go our way. It’s also behind that sudden pang of unease when we’re sitting at home and realize there’s a party we’re missing. The same kind of thinking fuels heated debates among fans of Tolkien or Sapkowski about how fictional worlds should look on screen. And it drives the excitement of scientists testing bold new hypotheses. In each case, it all comes back to the same question: “What would have happened if…?”
The question of counterpossibles
But counterfactuals become especially puzzling when their starting assumption is not merely false, but impossible. Consider: “If 2+2 were equal to 5, mathematics would collapse.” Or: “If a whale were a fish, it would have gills.” These are what philosophers call counterpossibles – counterfactual conditionals with impossible antecedents. And they pose a unique challenge.
According to the orthodox view, since the antecedent of a counterpossible can never be true, all counterpossibles come out trivially – or, as philosophers say, vacuously – true, regardless of what follows. “If a whale were a fish, it would have gills” would be just as true as “If a whale were a fish, it would have wings” – simply because a whale cannot be a fish. That conclusion strikes most of us as deeply unsatisfying.
Unorthodox approaches try to do better: they hold that we can meaningfully distinguish among counterpossibles, accepting some as true and rejecting others as false. The challenge, however, is explaining how. What makes this question significant beyond its apparent niche is that counterpossibles are not a special, exotic category – they arise from the very same kind of reasoning we use when we wonder what would have happened if we had caught an earlier train or chosen a different career. A satisfying theory of counterfactuals should be able to handle both the possible and the impossible in a unified way.
Drawing on both traditions, Prof. Maciej Sendłak of the Faculty of Philosophy at the University of Warsaw has proposed a new theory that aims to do just that. His proposal – the Dependence Account of Counterfactuals – starts from the idea that our beliefs about the world don’t exist in isolation; they’re connected to one another in complex ways. To assess whether a given counterfactual might be true, we need to consider both its consequences and the beliefs it rests on.
“We feel satisfied after passing an exam because we think, ‘If I hadn’t passed, all that work would have been for nothing.’ We feel regret after losing a loved one because we imagine, ‘If they were still here, we could go for a walk,’” explains Prof. Maciej Sendłak.
Statements like these feel true to us because they have plausible foundations and consequences that make sense in light of what we know about the world. In the Dependence Account, the truth of a counterfactual depends on how it connects to other judgments. For example, we’re inclined to accept the claim, “If Bolesław Chrobry – Poland’s first king [ed.] – had not been crowned, his state’s position would have been weaker,” because we recognize a link between holding a royal title and participating in medieval international politics.
“We justify counterfactuals by drawing on what we know about the actual world. The Dependency Account shows that the essence of counterfactual reasoning lies in real relations between states of affairs – regardless of whether we are considering an alternative course of history, an unreal experimental setup, or a purely logical abstraction,” Prof. Sendłak concludes.
Fictional worlds, real debates
Counterfactual conditionals lie at the foundation of art. They also shape how we interpret and engage with it. When we read a novel or watch a film, we – often without realizing it – constantly assess what in the fictional world is “true” and what is “false.” This is especially clear in genres such as fantasy and science fiction. The worlds created by writers and screenwriters engage our imagination insofar as they are internally coherent. This means that we treat certain assumptions about these worlds as true or false conditional claims.
That this is far from a trivial matter is evident in the heated debates that regularly flare up in both public discourse and online. Examples include the controversy surrounding the casting of Black actors as elves in Amazon Prime Video’s The Lord of the Rings: The Rings of Power, as well as ongoing disputes over the depiction of a dark-skinned vampire in Netflix’s adaptation of The Witcher. What may look like an argument about casting choices or character design is, at its core, a disagreement over competing counterfactual claims: “If elves existed, they would have a single skin tone” versus “If elves existed, they could have different skin tones.”
Science, too, relies heavily on reasoning about the impossible. At its core are hypotheses and their testing, and hypotheses are essentially conditionals: “If assumption X is correct, then we should observe Y.” Both the natural sciences and the humanities make extensive use of thought experiments – constructed scenarios, possible or impossible, designed to explore and solve theoretical problems. None of this would be possible without our ability to evaluate counterfactual claims as either true or false.
“An interesting application of counterfactual reasoning can be found in developmental psychology. One classic example is the so-called false-belief test, which examines whether a child can understand another person’s perspective. It ultimately comes down to reasoning such as: ‘If I thought like Johnny, I would believe that…’ Thought experiments – whether in ethics, physics, or philosophy – are entirely built on counterfactual reasoning. Each one places us in a situation that never actually occurred and asks us to draw conclusions from it. Another example is the well-known trolley problem, where we are asked what we would do – or what should be done – in a given scenario,” notes Prof. Sendłak.
FOMO and Conspiracy Theories
Counterfactuals lie at the core of how we think. Even when we’re not aware of it, our beliefs about the world are built on layers of underlying assumptions. This also applies to beliefs that can be potentially harmful – such as conspiracy theories. Prof. Sendłak argues, however, that the Dependence Account offers a way to effectively refute them.
“By testing conditionals, we can expose the internal inconsistencies in certain theories. ‘If the Earth were flat, a total lunar eclipse would be impossible.’ ‘If the moon landing had been staged in a studio, it would not have shown physical effects specific to the lunar environment – such as how people move in low gravity or how dust behaves in a vacuum,’” the scientist explains.
Another phenomenon closely linked to counterfactual thinking is FOMO (fear of missing out). It describes the anxiety we feel when we sense that we’re missing out on important events. In an age of information overload and constant social media updates, it has become an increasingly relevant challenge to emotional well-being. Experiencing FOMO can be as simple as picking up a smartphone: the sheer flow of information about what is happening “out there,” while we remain at home, can quickly become overwhelming.
FOMO follows a recognizable thought pattern. We observe a real-life situation – for example, friends posting from a concert we didn’t attend. We then construct a counterfactual alternative: “If I had gone with them, I’d have such great memories right now.” We compare it with our actual situation, and this comparison produces feelings of sadness and regret. In this sense, FOMO depends on imagining an alternative version of reality in which we acted differently and ended up better off. This is a typical conditional – if X, then Y – which we don’t question as false, but instead intuitively accept as true.
“FOMO and conditionals are closely intertwined, since FOMO is largely driven by counterfactual thinking. From the perspective of my theory, it’s worth noting that the causal relation we perceive in such situations – and which leads us to accept a conditional as true – may in fact be much weaker than we assume. Not every concert is great, and investing in stocks always involves risk. In other words, FOMO may reflect a simplified or cognitively distorted form of counterfactual reasoning. Our tendency to treat certain relations as self-evident can lead us to mistakenly assume that an alternative reality would necessarily be better,” concludes the researcher.
Philosophers will no doubt continue to explore the problem of counterfactuals, and it is only a matter of time before someone identifies the limitations of the theory developed at the University of Warsaw and proposes a new one. From the perspective of everyday life, however, what matters is that these reflections help us better understand ourselves – how unconscious inferences shape our emotions, and how the unactualized continues to shape the way we think.
The text was originally published in Polish on the Serwis Naukowy UW website on May 6, 2025.
It was updated in May 2026.
