I am not quite sure whether this belongs in Philosophy SE, but I couldn't think of a better SE, so I am posting it here. My question is, is it the fact that we have language that causes us to believe in possible worlds? As far as I know, other animals do not have language and so can't imagine the world being anything other than what it is. We humans have language and so can imagine and even speak about the world being different than what it actually is, like a world where unicorns and dragons exist. The reason I am asking this question is because I am one of the few people who believe that only the actual exists. I believe that the fact we have language and can speak about counterfactuals causes us to falsely believe that there are other possible worlds besides this one. Also, are there other philosophers who have written about this and made an argument similar to mine?

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    Why does imagining things require language? And playing out possible scenarios has obvious evolutionary advantages, so it is likely that all higher animals do it in some form. On the other hand, very few humans believe that possible worlds exist in the sense of the actual world, including people working on modal logic professionally. Lewis's view in this regard is a curiosity, and even he motivates it by pragmatic benefits, not some ingrained beliefs. You might be forcing an open door.
    – Conifold
    Feb 18, 2022 at 21:43
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    I would argue that many animals may have some imagination, in that they might imagine the presence of a predator/of prey at the slightest unusual sound. Also animals seen to dream during sleep, as indicated by similar physical reactions as humans during sleep.
    – tkruse
    Feb 19, 2022 at 0:03
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    David Lewis famously argued for his PW realism since none of the counterarguments he heard is convincing, and he specifically asserted he didn't believe PWs are caused or representable by sentences of some language, nor does he believe the actual world is not some sentences. A typical counterargument is based on the parsimony of Occam's razor principle, but he would say PWs are actually qualitative parsimony rather than quantitative parsimony and the former is good in any philosophical or empirical hypothesis. Non-Euclidean geometries which don't actually exist in our world lie somewhere Feb 19, 2022 at 0:35

3 Answers 3


First of all it's best not to ask such questions by making general statements about animals. Those are often flawed, but also irrelevant distractions to the question.

The reason I am asking this question is because I am one of the few people who believe that only the actual exists.

This would logically indicate that the ability to use language does not force anyone to believe in other worlds. But that statement itself also seems debatable, both what you say about yourself and what you say about others, but that is also irrelevant.

It seems obvious that the ability to communicate about a distant past (e.g yesterday, or 100years ago), to recount a story, implies the ability to lie about the past, and thus also for others to believe in such lies/fabrications.

But it seems impossible to prove philosophically that anyone or anything lacking the ability to communicate in such structured language that way also lacks the ability to imagine fantasy worlds and believe in those. A study of so-called feral children could reveal something, but would face plenty of technical difficulties.

As food for thought, consider how dolphins might imagine the world of things living outside water on land, and whether two different dolphins might imagine that quite differently.


Without language an intelligent being (human or otherwise) could imagine a counter-factual scenario. A dog waiting sadly by the door for its owner certainly seems to be imagining the scenario in which the owner shows up suddenly, even if in fact the owner won't be home for many hours.

However, the concept of a possible world as used in philosophy is a bit more specific than simply an imagined scenario. It is usually associated with modal logic, which is a system of syntax and semantics for propositions. For the proposition "P is possible" to be true it has to be true at some possible world. Note, this is neutral as to the metaphyiscal status of possible worlds. They may be seen as really existing (modal realism) or as mental simulations, or just as featureless elements in the abstract set of worlds from a formal logical semantics. However, they are understood, the possible worlds play the role of giving truth values to modal propositions like "P is possible" or "P is necessary". So in this logical sense I would say that believing in possible worlds does require language (in so far as it is plausible that understanding formal logic requires language). This doesn't mean that the metaphysical entity which corresponds to the logicians "world" depends on language, it might or might not depending on whether one is a modal realist or not. Even if one is not a modal realist, there is at least one possible world the existence of which does not depend on language, that is the actual world, since actuality implies possibility!


You may believe that only the actual exists, but speculating about possibilities is an important activity, and there is considerable advantage in being able to do it well. Suppose a prehistoric tribe endured a long winter and reached the end of their stored food, and the spring arrived just in time to prevent them starving. They would be well served by reasoning counterfactually that if the winter had lasted any longer they would have died. This provides a motivation for expanding their winter stores for future contingencies, so it has survival value.

We also think about possibilities when interacting with other people. This person looks threatening, so I will prepare myself to fight or run away. That person might try to cheat me in a business deal, so I will draw up a contract that will specify what remedies are available if they do. We also treat our own choices as involving possibilities. If I had made different choices when I was younger, I could have been a lawyer. But if I had made different choices, I could not have been an olympic athlete.

Indeed, reasoning about causation quite generally involves being able to judge that if this were to happen then that would follow, or if this had happened, then that would have followed. So reasoning about possibilities is vital, and not just for human beings but for other animals too. And not just in ways that involve language.

To speak of possible worlds is one helpful way of making sense of these possibilities. To say that something is possible can be represented as saying that there is a possible world in which it is true. This helps us to explain the logic of counterfactual conditionals. It helps us to distinguish between necessary and contingent truths. It helps us to explain the meaning of intensional concepts. Whether these possible worlds really exist, as David Lewis maintained, or whether they are just some kind of useful fiction, is another question, and is the subject of a fair bit of philosophical debate.

  • Personally, I thibk a posdible world is somewhat different from a world that could be possibly different. Feb 19, 2022 at 20:02

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