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Factual Conditional Sentences:

Factual conditionals include four types: generic, habitual, implicit inference, and explicit inference.

Generic Factual Conditionals:

They express relationships that are true and unchanging; for example:

• If oil is mixed with water, it floats. • If you boil water, it vaporizes.

Because of their unchanging truth value, these conditionals normally take a simple present tense in both clauses. They are especially frequent in scientific writing, since the sciences are often concerned with such absolute relationships.

FORM: If + SIMPLE PRESENT, SIMPLE PRESENT

Habitual Factual Conditionals:

Habitual factual conditionals resemble generic factuals in that they also express a relationship that is not bounded in time; however, the relationship is based on habit instead of physical law. They express either past or present relationships that are typically or habitually true; for example:

• If I wash the dishes, Sally dries them. • If Nancy said, “jump!” Bob jumped.

This type of conditional is frequent in conversation. Both clauses usually have the same tense: simple present in both clauses if the habitual relationship refers to extended present time; simple past in both clauses if the sentence refers to a past habit.

Note that for both generic and habitual conditionals it is possible to substitute when or whenever for if and still express more or less the same idea:

• When(ever) you boil water, it vaporizes. • When(ever) I wash the dishes, sally dries them.

FORM:

• IF + SIMPLE PRESENT, SIMPLE PRESENT • IF + SIMPLE PAST, SIMPLE PAST

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Implicit Inference Conditionals:

Factual conditionals that express an implicit inference are different from generic and habitual factuals in that they express inferences about specific time-bound relationships. As such, they make use of a much wider range of tense and aspect markers, and they also occur with certain modal auxiliaries.

• If smog can be licked in L.A., it can be licked anywhere. • If the radicals haven’t made the government more responsive, they have wasted their time. • If there was a happy man in the world that night, it was John Tunney. • If you’ll bring some wine, I’ll bring some beer and potato chips. • If it’s Tuesday, it’s Sam’s birthday.

Implicit inference conditionals, like their habitual counterparts, are conversational in flavor, and like generic and habitual factuals, implicit inference factuals tend to maintain the same tense and aspect or the same modal in both clauses – even though they make use of a wider range of tenses and auxiliary verbs. However, implicit inference factuals differ from generic and habitual factuals in that when or whenever cannot substitute for if without changing the meaning and often making the sentence ungrammatical or, nonsensical:

• When(ever) it’s Tuesday, it’s Sam’s birthday. (wrong)

FORM: IF + TAMx, TAMx1

Explicit Inference Factual Conditionals:

The final type of factual conditional, the explicit inference conditional, is the only case where there is no strict parallelism of tense, aspect, or modal in both clauses. This is because the conditional (i.e., the if clause) is used as the basis for making an explicit inference; the result clause thus contains an inferential modal – typically must or should: • If someone’s at the door, it must be Peter. • If anyone has the answer, it should be Robert.

Explicit inferential factuals are similar to implicit inference factuals in that both refer to more specific time-bound events or states in the if clause. Also, both involve making inferences; however, only the explicit inference factual conditional overtly marks the inferential process with a modal. Explicit inference conditionals, however, are more limited in range, since they cannot occur with the same variety of tense and modal combinations that implicit inferences do. Like implicit inference conditionals, explicit inference conditionals can refer to past as well as present time (by adding have to must or should):

• Past implicit inference: If he was there, he saw the painting. • Past explicit inference: If he was there, he must have seen the painting.

FORM: IF + TAM, (MUST/SHOULD)VP

1 TAM = any possible combination of tense, aspect, modals, and phrasal modals.