# Modal fictionalism

Modal fictionalism is a term used in philosophy, and more specifically in the metaphysics of modality, to describe the position that holds that modality can be analysed in terms of a fiction about possible worlds. The theory comes in two versions: Strong and Timid. Both positions were first exposed by Gideon Rosen starting from 1990.

## Types

Modal fictionalism is a philosophical perspective that centers on the assertion that possible worlds are fictional entities. This perspective seeks to explain our apparent commitment to possible worlds in a manner akin to our engagement with other fictional constructs, such as ideal gases or frictionless surfaces. One of the pioneering works in this field was presented by Rosen in 1990, wherein he and other scholars formulated modal fictionalism as a theory equating talk of possible worlds with discussions about paradigmatically fictional objects, such as Sherlock Holmes. For example, statements like "There is a (non-actual) possible world at which there are blue swans" are understood through an analogy with "There is a brilliant detective at 221b Baker Street," as proposed by Rosen.
Modal fictionalism involves at least a partial account of how paradigmatically fictional claims are to be treated, asserting that these claims are, in a literal and strict sense, false. According to modal fictionalists, there are no merely possible worlds, situations, outcomes, or objects. In strict terms, there is no sculpture created on a particular morning, even though the potential for its creation existed. Similarly, when a coin flip results in heads, there is no outcome in which it lands tails, strictly speaking.
However, within the context of the modal fiction or the fiction of possible worlds, there exists a (merely possible) sculpture that could have been created that morning and an (unactualized) outcome where the coin lands tails. While discussions about merely possible worlds and objects are generally literally false, more elaborate discussions about what is true according to the fiction of possible worlds are considered literally true.
Some proponents of modal fictionalism, such as Hinckfuss (1993), suggest that discussions about possible worlds should be governed by implicit presuppositions known to be false. This approach ensures that statements in the language of possible worlds do not necessitate a belief in their actual existence but rather commit one to more economical propositions, such as "if there were possible worlds of a certain kind, then..." or "given the presupposition that there are possible worlds...". Alternatively, other accounts of how talk about possible worlds functions may be proposed. For instance, Nolt (1986) proposes treating typical "possibilistic discourse" as a form of make-believe, although the specific theory of make-believe is not explicitly defined. Notably, Stephen Yablo (Yablo 1996) employs Walton's theory of make-believe in his modal fictionalism, which he also refers to as figuralism.
One of the primary advantages of adopting a fictional approach to possible worlds is the ability to utilize the language of possible worlds without committing to their literal existence. This approach is particularly appealing when considering merely possible objects, such as blue swans or dragons, which are often characterized by their non-actual existence.
Central to modal fictionalism are biconditionals that establish connections between truths about necessity and possibility and the contents of the modal fiction. These biconditionals, exemplified by schemas like "Possibly P iff according to the fiction of possible worlds, P is true at some possible world" and "Necessarily P iff according to the fiction of possible worlds, P is true at all possible worlds," are crucial for understanding the relationship between modal claims and the modal fiction. While these biconditionals can inter-define necessity and possibility, their precise workings may vary among different modal fictionalists.
In conclusion, modal fictionalism offers a unique perspective on the nature of possible worlds, allowing for the exploration of these concepts while avoiding the ontological commitment to their actual existence. The diversity of approaches within modal fictionalism highlights the rich philosophical discussions and debates surrounding this intriguing viewpoint.

## Strong fictionalism about possible worlds

According to strong fictionalism about possible worlds (another name for strong modal fictionalism), the following bi-conditionals are necessary and specify the truth-conditions for certain cases of modal claims:
* It is possible that P iff the translation of P into the language of a fiction F (containing possible worlds) holds according to F.
* It is necessary that P iff the translation of P into the language of a fiction F (containing possible worlds) always holds.
Recent supporters of this view added further specifications of these bi-conditionals to counter certain objections. In the case of claims of possibility, the revised bi-conditional is thus spelled out: (1.1) it is possible that P iff At this universe, presently, the translation of P into the language of a fiction F holds according to F.

## Timid fictionalism about possible worlds

According to a timid version of fictionalism about possible worlds, our possible worlds can be properly understood as involving reference to a fiction, but the aforementioned bi-conditionals should not be taken as an analysis of certain cases of modality.

## Objections and criticisms

Modal fictionalism has encountered various objections and concerns on more conceptual and philosophical grounds. These concerns are not uniformly applicable to all forms of modal fictionalism and often target specific versions of the doctrine.

### Artificiality

One significant concern relates to the artificial nature of fictions. Fictional stories are human creations, typically authored by individuals who exercise a significant degree of control over the content and truth within those narratives. When considering modal fictionalism, it becomes evident that not just any narrative about possible worlds can serve as the modal fiction, especially if it is meant to provide heuristic and explanatory advantages similar to realist theories of possible worlds. The worry here is that talk of possible worlds may not be as flexible as typical fictional narratives, as the choice of which story about possible worlds should be the modal fiction might not be entirely within our discretion.
Modal fictionalists can argue that the constraints of the fiction are necessary, just as specific constraints govern the creation of fictional stories about other topics. However, defining these constraints can be challenging, and determining why they are appropriate is no simple task. Even if such constraints are established, there may still be a degree of artificiality in the choice of details left undetermined by these constraints, though this is unlikely to be a fatal problem.
A more specific concern arises regarding the contingency of whether a modal fiction exists at all. If sentient beings had never existed, no stories about possible worlds would have been told. Even if modal fiction is viewed as a Platonic entity (such as a collection of propositions), it might not have been considered fiction if it had never been expressed by storytellers. This concern is particularly relevant when modal truth is thought to depend on the contents of the fiction, as the possibility of blue swans, for instance, should not be contingent upon whether stories have been told. Various responses to this concern have been proposed in the literature.

### Incompleteness

Fictions, including modal fictions, often exhibit incompleteness by being silent on certain issues. For example, the Sherlock Holmes stories do not specify the exact population of India or the number of hairs on Dr. Watson's head. Similarly, the modal fiction might also exhibit incompleteness, leaving some propositions without determinate truth values within the fiction.
This incompleteness can pose challenges. For instance, there is the "incompleteness problem," where a fictionalist may remain silent on certain modal issues, not because they believe there is no answer, but because the fiction itself is silent on those issues. This can lead to difficulties in determining the truth or falsity of related modal claims. Different solutions have been proposed, including treating modal claims as indeterminate when the fiction is silent on corresponding questions about possible worlds.
Another concern is that a modal fiction must represent a vast amount of information about possible worlds, as there are infinitely many claims about possible worlds necessary to correspond to all modal claims. However, the finite resources of description can limit the extent to which these propositions can be explicitly stated. While generalizations about possible worlds can help, strong modal fictionalists aiming to reductively analyze modality in terms of the fiction face challenges in representing the implicit content of the fiction without relying on modal notions like implication.

### Selection of fiction

A critical aspect of modal fictionalism is the specification of the fiction of possible worlds to be used. Selecting one from many potential candidate stories and justifying this choice is essential, yet often overlooked. While some modal fictionalists offer justifications, many do not.
Timid modal fictionalism provides a straightforward answer to this question by relying on independently obtaining modal truths. Strong modal fictionalists, however, must ensure that the content of the fiction aligns with the modal claims they wish to make. Nonetheless, this doesn't help them determine the content of the fiction itself. Specifying this content without relying on modal notions like implication is a challenge faced by strong modal fictionalists.
Constraints on the choice of fiction may be drawn from various sources, such as conformity with pre-theoretic modal judgments, inclusion of literal truths about our actual world, and considerations of our imaginative practices when forming modal beliefs. Even with these constraints, there might still be multiple equally suitable fictions, raising questions about how to handle differing fictional choices and their implications for modal claims.

### Theoretical primitives

Modal fictionalism relies on the "According to PW..." operator as a central theoretical tool. This operator poses a challenge, as it appears to be a modal notion. For modal fictionalists interested in analyzing modality in terms of their fiction, this operator should not be analyzed in terms of standard modal devices or possible worlds. Whether it should be considered a primitive or analyzed further remains a matter of debate and is a concern for those seeking a reductive analysis of modality.

### Possible worlds semantics

Some philosophers have argued that modal fictionalism may not provide all the benefits of standard possible worlds semantics for modal discourse. John Divers, in particular, has raised objections to this aspect of modal fictionalism, questioning whether it can fully capture the advantages of traditional possible worlds semantics.

### Three more concerns

Modal fictionalism has also faced additional objections and concerns:
* The Threat from Abstractionism: Abstractionist realists treat possible worlds as representational entities similar to fictions. This poses a challenge for modal fictionalists who need to explain why they prefer fictional narratives over abstractionist realism.
* Concern About Concern: Analogous to Kripke's argument from concern, this concern questions whether individuals genuinely care about modal claims being framed as claims about a fiction of possible worlds rather than directly about the subject matter in question.
* About Aboutness: This concern revolves around the notion that the paraphrases of modal claims in terms of a fiction of possible worlds may not be about the same things as the original modal claims, potentially affecting the core point of modal claims being about their subject matter.
These concerns are part of ongoing debates surrounding modal fictionalism and its compatibility with various philosophical positions.