Indicativity definition
Executive summary
"Indicativity" names different but related ideas across linguistics, logic, and epistemology: it derives from the grammatical indicative mood (used for straightforward statements) and from the family of natural-language “if…then” sentences called indicative conditionals, while in epistemology it appears as a probabilistic condition connecting belief and the evidence that allegedly makes that belief indicative of the world; each usage is contested and lacks a single, uncontroversial technical definition [1] [2] [3].
1. What the term comes from: the indicative mood and ordinary usage
At its broadest, indicativity traces to the indicative mood in grammar, the default form used to make statements or ask plain questions (for example, "I saw her yesterday"), and that grammatical sense underlies ordinary talk of something being “indicative” of a fact or state of affairs [1].
2. Indicative conditionals: everyday “if” sentences and the puzzle they create
In semantics the most prominent locus for “indicative” is the class of indicative conditionals—natural-language if‑sentences such as “If the train is on time, we’ll be home by ten”—which ordinary speakers use to talk about what may actually be the case and which are traditionally contrasted with subjunctive or counterfactual conditionals (e.g., “If the train had been on time, we would have been home”) [4] [2].
3. Why philosophers and logicians debate indicativity: truth, probability, and semantics
Despite everyday fluency with such conditionals, philosophers report serious difficulties in giving them clean truth‑conditional or probabilistic analyses: some argue that standard truth‑functional reconstructions (the material conditional) fail, others propose modal/possible‑world accounts like Stalnaker’s nearest‑world idea, some treat indicatives as strict conditionals ranging over possible worlds, and yet critics point to Lewis‑style triviality results and other technical pressures that show no simple proposition will always have probability equal to P(B|A), so no single agreed formal definition exists [5] [2] [4] [6].
4. Competing theoretical moves in the literature
The literature offers several competing strategies: (a) world‑similarity/selection accounts (e.g., Stalnaker) that evaluate “If A, B” by looking at the most relevant A‑worlds in the conversational context (but face questions about similarity metrics and uniqueness), (b) strict‑conditional or modal reconstruals that quantify over ranges of worlds, and (c) non‑truth‑conditional or assertibility approaches that treat indicative conditionals as graded in acceptability rather than simply true/false; the Routledge entry and Stanford Encyclopedia survey these options and record ongoing disagreement [4] [7] [2].
5. Indicativity in epistemology: a probabilistic condition on knowledge
Separate from conditionals, epistemologists such as Igal Kvart have used an “indicativity condition” to capture a probabilistic intuition about knowledge: roughly, a content p is indicative for a subject when the chance of p is higher given that the subject believes p than otherwise, with that discriminability or “indicativeness” intended to ground why belief tracks truth in perceptual or memory cases; this is presented as part of a probabilistic, externally‑oriented account of knowledge [3].
6. How the different senses connect and why distinctions matter
Though the grammatical/semantic sense (indicative mood and indicative conditionals) and the epistemological sense (probabilistic indicativity) are distinct moves, they converge on a common intuition: something is “indicative” when it points toward actual states of affairs—whether a sentence form that purports to describe real possibilities or an evidential relation that raises the probability of a proposition—and debates in each field turn on whether that pointing admits a simple, context‑free formalization [1] [4] [3].
7. Where certainty ends and controversy begins: practical implications and limits of consensus
Practically, the lack of consensus matters for logic, probability theory, and philosophy of language: it affects how conditional reasoning is modeled in formal systems and how one formulates epistemic norms linking belief and evidence; but the sources make clear that no single definition of “indicativity” survives scrutiny across all contexts, so careful writers should specify whether they mean the grammatical mood, the class of indicative conditionals, or Kvart‑style probabilistic indicativity when invoking the term [5] [4] [3].
8. Final note on sourcing and open questions
This account synthesizes descriptive entries and analytic literature: grammatical definitions of the indicative (Encyclopedia.com), encyclopedic treatments of conditionals and debates (Stanford Encyclopedia, Routledge), technical alternatives including strict‑conditional proposals (Argumenta), and the epistemological indicativity project (Kvart); the record shows persistent pluralism rather than a single, authoritative technical meaning [1] [4] [7] [6] [3].