Conditional sentences are natural language sentences that express that one thing is contingent on something else, e.g. "If it rains, the picnic will be cancelled." They are so called because the impact of the main clause of the sentence is conditional on the dependent clause. A full conditional thus contains two clauses: a dependent clause called the antecedent (or protasis or if-clause), which expresses the condition, and a main clause called the consequent (or apodosis or then-clause) expressing the result.

Languages use a variety of grammatical forms and constructions in conditional sentences. The forms of verbs used in the antecedent and consequent are often subject to particular rules as regards their tense, aspect, and mood. Many languages have a specialized type of verb form called the conditional mood – broadly equivalent in meaning to the English "would (do something)" – for use in some types of conditional sentences.

Types of conditional sentence

There are various ways of classifying conditional sentences. Many of these categories are visible cross-linguistically.

Implicative and predictive

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A conditional sentence expressing an implication (also called a factual conditional sentence) essentially states that if one fact holds, then so does another. (If the sentence is not a declarative sentence, then the consequence may be expressed as an order or a question rather than a statement.) The facts are usually stated in whatever grammatical tense is appropriate to them; there are not normally special tense or mood patterns for this type of conditional sentence. Such sentences may be used to express a certainty, a universal statement, a law of science, etc. (in these cases if may often be replaced by when):

If you heat water to 100 degrees Celsius (° C), it boils.
If the sea is stormy, the waves are high.

They can also be used for logical deductions about particular circumstances (which can be in various mixtures of past, present, and future):

If it's raining here now, then it was raining on the West Coast this morning.
If it's raining now, then your laundry is getting wet.
If it's raining now, there will be mushrooms to be picked next week.
If he locked the door, then Kitty is trapped inside.

A predictive conditional sentence concerns a situation dependent on a hypothetical (but entirely possible) future event. The consequence is normally also a statement about the future, although it may also be a consequent statement about present or past time (or a question or order).

If I become President, I'll lower taxes.
If it rains this afternoon, everybody will stay home.
If it rains this afternoon, then yesterday's weather forecast was wrong.
If it rains this afternoon, your garden party is doomed.
What will you do if he invites you?
If you see them, shoot!

Indicative and counterfactual

See also: English conditional sentences, Counterfactual conditional, and Indicative conditional

One of the most discussed distinctions among conditionals is that between indicative and counterfactual conditionals, exemplified by the following English examples:

These conditionals differ in both form and meaning. The indicative conditional uses the present tense forms "owns" and "beats" and therefore conveys that the speaker is agnostic about whether Sally in fact owns a donkey. The counterfactual example uses the fake tense form "owned" in the "if" clause and the past-inflected modal "would" in the "then" clause.[1] As a result, it conveys that Sally does not in fact own a donkey.[2] Similar contrasts are common crosslinguistically, though the specific morphological marking varies from language to language.[3][4][5][6]

Linguists and philosophers of language sometimes avoid the term counterfactuals because not all examples express counterfactual meanings. For instance, the "Anderson Case" has the characteristic grammatical form of a counterfactual conditional, but is in fact used as part of an argument for the truth of its antecedent.[7][8]

Anderson Case: If Jones had taken arsenic, he would have shown just exactly those symptoms which he does in fact show.[9]

The term subjunctive conditional has been used as a replacement, though it is also acknowledged as a misnomer. Many languages do not have a subjunctive (e.g., Danish and Dutch), and many that do have it don’t use it for this sort of conditional (e.g., French, Swahili, all Indo-Aryan languages that have a subjunctive). Moreover, languages that do use the subjunctive for such conditionals only do so if they have a specific past subjunctive form. [10][11][12] The term X-Marked has been used as a replacement, with indicative conditionals renamed as O-Marked conditionals.[13][14][15]

Speech act conditionals

Biscuit conditionals (also known as relevance or speech act conditionals) are conditionals where the truth of the consequent does not depend on the truth of the antecedent.

In metalinguistic conditionals, the antecedent qualifies the usage of some term. For instance, in the following example, the speaker has unconditionally asserted that they saw the relevant person, whether or not that person should really be called their ex-husband.[17]

Non-declarative conditionals

In conditional questions, the antecedent qualifies a question asked in the consequent.[18][19]

In conditional imperatives, the antecedent qualifies a command given in the consequent.[20]

Crosslinguistic variation

Languages have different rules concerning the grammatical structure of conditional sentences. These may concern the syntactic structure of the antecedent and consequent clauses, as well as the forms of verbs used in them (particularly their tense and mood). Rules for English and certain other languages are described below; more information can be found in the articles on the grammars of individual languages. (Some languages are also described in the article on the conditional mood.)


Main article: Latin conditional clauses

Conditional sentences in Latin are traditionally classified into three categories, based on grammatical structure.

sī valēs, gaudeo "if you are well, I am glad"
  • past tense [if perfect indicative then indicative]
sī peccāvī, īnsciēns fēcī "if I did wrong, I did so unwittingly"
  • 2nd person generalisations [if present or perfect subjunctive then indicative]
memoria minuitur, nisi eam exerceās "memory gets weaker, if you don't exercise it"
haec sī attulerīs, cēnābis bene "if you bring (literally "will have brought") these things, you will dine well"
  • "future less vivid" [if present or perfect subjunctive then present subjunctive]
sī negem, mentiar "if I were to deny it, I would be lying"
scrīberem plūra, sī Rōmae essēs "I would write more, if you were in Rome"
  • "past contrary-to-fact" [if pluperfect subjunctive then pluperfect subjunctive]
sī Rōmae fuissem, tē vīdissem "if I had been in Rome, I would have seen you"


In French, the conjunction corresponding to "if" is si. The use of tenses is quite similar to English:

As in English, certain mixtures and variations of these patterns are possible. See also French verbs.


Italian uses the following patterns (the equivalent of "if" is se):

See also Italian verbs.

Slavic languages

In Slavic languages, such as Russian, clauses in conditional sentences generally appear in their natural tense (future tense for future reference, etc.) However, for counterfactuals, a conditional/subjunctive marker such as the Russian бы by generally appears in both condition and consequent clauses, and this normally accompanies the past tense form of the verb.

See Russian grammar, Bulgarian grammar, etc. for more detail.


While the material conditional operator used in classical logic is sometimes read aloud in the form of a conditional sentence, the intuitive interpretation of conditional statements in natural language does not always correspond to it. Thus, philosophical logicians and formal semanticists have developed a wide variety of conditional logics that better match actual conditional language and conditional reasoning. They include the strict conditional and the variably strict conditional.[21][22][23]

See also


  1. ^ This use of past tense is often called fake past since it does not contribute a normal past tense meaning. See Iatridou (2000), Karawani (2014), Mackay (2015), among others.
  2. ^ Huddleston, Rodney; Pullum, Geoff (2002). The Cambridge Grammar of the English Language. Cambridge University Press. p. 150. ISBN 978-0521431460.
  3. ^ von Prince, Kilu (2019). "Counterfactuality and past" (PDF). Linguistics and Philosophy. 42 (6): 577–615. doi:10.1007/s10988-019-09259-6. S2CID 181778834.
  4. ^ Karawani, Hadil (2014). The Real, the Fake, and the Fake Fake in Counterfactual Conditionals, Crosslinguistically (PDF) (Thesis). Universiteit van Amsterdam. p. 186.
  5. ^ Schulz, Katrin (2017). "Fake Perfect in X-Marked Conditionals". Proceedings from Semantics and Linguistic Theory. Semantics and Linguistic Theory. Linguistic Society of America. pp. 547–570. doi:10.3765/salt.v27i0.4149.
  6. ^ Huddleston, Rodney; Pullum, Geoff (2002). The Cambridge Grammar of the English Language. Cambridge University Press. pp. 85–86. ISBN 978-0521431460.
  7. ^ von Fintel, Kai (1998). "The Presupposition of Subjunctive Conditionals" (PDF). In Sauerland, Uli; Percus, Oren (eds.). The Interpretive Tract. Cambridge University Press. pp. 29–44.
  8. ^ Egré, Paul; Cozic, Mikaël (2016). "Conditionals". In Aloni, Maria; Dekker, Paul (eds.). Cambridge Handbook of Formal Semantics. Cambridge University Press. p. 515. ISBN 978-1-107-02839-5.
  9. ^ Anderson, Alan (1951). "A Note on Subjunctive and Counterfactual Conditionals". Analysis. 12 (2): 35–38. doi:10.1093/analys/12.2.35.
  10. ^ Iatridou, Sabine (2000). "The grammatical ingredients of counterfactuality". Linguistic Inquiry. 31 (2): 231–270. doi:10.1162/002438900554352. S2CID 57570935.
  11. ^ Kaufmann, Stefan (2005). "Conditional predictions". Linguistics and Philosophy. 28 (2). 183-184. doi:10.1007/s10988-005-3731-9. S2CID 60598513.
  12. ^ Egré, Paul; Cozic, Mikaël (2016). "Conditionals". In Aloni, Maria; Dekker, Paul (eds.). Cambridge Handbook of Formal Semantics. Cambridge University Press. p. 515. ISBN 978-1-107-02839-5.
  13. ^ von Fintel, Kai; Iatridou, Sabine. Prolegomena to a theory of X-marking Unpublished lecture slides.
  14. ^ von Fintel, Kai; Iatridou, Sabine. X-marked desires or: What wanting and wishing crosslinguistically can tell us about the ingredients of counterfactuality Unpublished lecture slides.
  15. ^ Schulz, Katrin (2017). Proceedings from Semantics and Linguistic Theory. Semantics and Linguistic Theory. Vol. 27. Linguistic Society of America. pp. 547–570. doi:10.3765/salt.v27i0.4149.
  16. ^ "Language Log » If you think about it".
  17. ^ Dancygier, Barbara; Sweetser, Eve (1996). "Conditionals, distancing, and alternative spaces" (PDF). In Goldberg, Adele (ed.). Conceptual structure, discourse and language. CSLI Publications. pp. 83–98.
  18. ^ Velissaratou, Sophia (1901). Conditional questions and which-interrogatives (M.Sc.). Universiteit van Amsterdam, ILLC.
  19. ^ Isaacs, James; Rawlins, Kyle (2008). "Conditional questions". Journal of Semantics. 25 (3): 269–319. doi:10.1093/jos/ffn003.
  20. ^ Kaufmann, Stefan; Schwager, Magdalena (2009). A unified analysis of conditional imperatives. Semantics and Linguistic Theory. Linguistic Society of America. pp. Proceedings of SALT.
  21. ^ Starr, Will (2019). "Counterfactuals". In Zalta, Edward N. (ed.). The Stanford Encyclopedia of Philosophy.
  22. ^ Egré, Paul; Rott, Hans (2021). "The Logic of Conditionals". In Zalta, Edward N. (ed.). The Stanford Encyclopedia of Philosophy.
  23. ^ Egré, Paul; Cozic, Mikaël (2016). "Conditionals". In Aloni, Maria; Dekker, Paul (eds.). Cambridge Handbook of Formal Semantics. Cambridge University Press. p. 515. ISBN 978-1-107-02839-5.