A bare bones definition for fiction:
1. A fiction is a text of a (centred) world that references some other world while omitting, for at least some claims, conditionals that indicate otherworldly reference.
Three criteria for a (valid) fiction make this definition more substantive:
a. At least one statement is false for the centred world at which the text is read.
b. All sentences or claims are true at a centred world for some possible world.
c. Some sentences are written as though true for the centred world at which the text is read.
A few explanatory notes and caveats
i. A centred world is the world at which a text is written. A fictional world is a world referenced in such a text. In this case, fictionality can be characterised as a relation on a pair of worlds (wRfw) – a centred world and a fictional world – where a text at one makes reference to the other.
ii. A fictional world is not inherently a fictional world, in and of itself, but earns that status as a consequence of being the subject of a text at another world. Where the relation holds between a pair of worlds, the referenced world is a fictional world.
iii. Non-fiction texts reference the world at which the text is. Fictional texts are those that fail to accurately represent this centred world: their propositions contradict what is true. This is a determination made in every instance by an agent at a world evaluating a text. Once the reader notes that the text does not reference this world, a different set of assumptions come into play about how the text should be treated in terms of truth and veracity.
iv. Some proposition in a fictional text is ‘erroneously’ indexed to the world of the text, rather than the world of the content: as though the text were non-fiction. This means that a text overtly detailing events properly placed at some other world is not fiction. Which is to say, if a text begins every proposition by saying ‘At some possible world it may be the case that..’ it is not, strictly, a fictional text, despite otherworldly reference. There is a kind of fallacy, then, inherent in fiction by virtue of a claim that refers improperly, Otherworldly reference is always improperly indexed in at least some statements. Fictional texts omit operators in sentences. Otherwise, they would be non-fiction texts about possible worlds, or extended claims about what is possible. The ‘error’, though – the logical fallacy – serves as a device.
v. Reference to a ‘valid’ fiction indicates a specific problem for a model grounded in the idea of referring to other worlds. If a claim for this sort of reference holds water it is because the possibility that other worlds exist cannot be excluded, and so a given fiction may hold true at such a world. What then of texts that we determine as asserting, via a set of sentences, a situation that is impossible, by virtue, perhaps, of contradictions contained in the text? If it is accepted that a fiction may refer to elements, characters, events at a possible world, this cannot be said for fictions that make claims about the furniture of impossible worlds. There is, in this case, no possible world to make good referential claims, even in a conditional way. Yet such texts remain fiction according to a normative definition. To argue, against this definition, that these are not fictions at all, would represent a kind of extremism. The alternative adopted here is to talk instead of a ‘valid fiction’ as one that has, as point of reference, a possible world, and to describe as an ‘invalid fiction’ a text that makes claims concerning an impossibility. In the former case elements of a fictional world are referenced, whereas in the latter case, claimed reference fails.
vi. One way to look at this concession is to say that in grounding a typology of texts in the normative categories ‘fiction’ and ‘non-fiction’, what has really happened is that at least four kinds of texts have been shoe-horned into two broad categories. This is, it should be said, the normal result of taking a set of cases covered by a binary pair of truth values, and extending the range of truth values available to allow for the truth, or otherwise, of modal claims.
The four text types are the following:
1. non-fiction texts comprised of claims that are necessarily true, or true for all worlds
2. non-fiction texts comprised of ‘actually’ true claims, true for the world at which the text is evaluated.
3. fictional texts comprised of claims that are possibly true, true for some possible world
4. fictional texts comprised of claims that are not possibly true – true for no world at all.
Hence the division by which two kinds of fiction described above, 3. and 4., are labelled ‘valid fictions’ and ‘invalid fictions’ respectively.
vi. Two further limitations are worth mentioning here. The first, leading to the second, is that this sort of talk of possible worlds is not reductive in an ideal way, such that a sentence ‘p is possibly true’ can be equated with ‘p is true for some world’. The strongest claim that can be made about what holds at other worlds is ‘p is possibly true for some world’. In the conditional part of this claim lies all of our worries on the question as to the existence of possible worlds. If possible worlds do exist, we may further speculate on which of them have existence. Is it all possible worlds that are corporeal, or only some? If the latter is the case, can we apply criteria in determining which have existence, or is it, at least in part, an arbitrary matter?
The second limitation, as promised, is an epistemic constraint on the knowledge of an agent at a world as to which worlds have corporeal existence (and, it can be added, which worlds are impossible – could not exist – as set against those that merely do not). While questions of this sort cannot be answered in a definitive way concerning texts that are evaluated by agents at worlds for truth a further conditional clause might be placed on a rendering of sentences in general, ergo:
‘p is believed true’
In this case, and taking into account the four-fold typology of texts, sentences in a text that is deemed non-fiction may be rendered as (1) ‘p is believed true for all worlds’ or (2) ‘p is believed true for this world’. A text determined to be fiction is one containing sentences rendered either as (3) ‘p is believed possibly true for some world, or (4) ‘p is believed true for no world’.
see also: Polemic: why argue for truth in fiction