Conditional Sentences


In this lecture our concern is not with subtleties in the logical or semantic properties of conditional sentences, but with the tight connection between the meanings of English conditional sentences and features of their grammatical form.

In a conditional sentence, there are two parts, (1) the antecedent = the protasis, and (2) the consequent = the apodosis. In general I will refer to them simply as "P" and "Q", from the logician's tradition of representing material implication as "P implies Q".

Most of the examples we consider will be of the form "if P, Q", but actually there are numerous ways of expressing the meanings that get expressed in English conditional sentences. Here are some examples:

  1. "If you come closer, you'll be able to see the parade."
    (the form we'll mainly be considering)
  2. "Unless you come closer you won't be able to see the parade."
    (If you don't stand closer, you won't be able to see the parade)
  3. "Do you like it? It's yours!"
    (If you like it, it's yours)
  4. "Come here and I'll give you a kiss."
    (If you come here, I'll give you a kiss.)
  5. "Criticize him the slightest bit and he starts crying."
    (If you criticize him the slightest bit, he starts crying.)
  6. "Get out of here or I'll call the police."
    (If you don't get out of here I'll call the police.)
  7. "Anyone who does that deserves to be punished."
    (If anyone does that, they deserve to be punished.)
  8. "With his hat on he would look older."
    (If he had his hat on, he would look older.)
  9. "Otherwise, I wouldn't be here."
    (If things were not the way they are, I wouldn't be here.)

Our main examples will be of type (1) above, marked by the introducer "if", and with the antecedent or subordinate clause preceding the consequent or main clause. (Hence, "if P,Q".)

Dependencies in Conditional Clauses

It is common to think of "if" in English as a kind of conjunction, and to think of the meaning of a conditional sentence as a straightfoward product of the meanings of its component clauses. In the simplest way of thinking of this, the truth of a conditional sentence is a product of the truth values of its individual clauses, according to a truth-table that holds the full sentence to be true unless the P part is true while the Q part is false.

This implies, of course, that each of the parts of a conditional sentence could stand on its own, and could have its truth determined independently of the other. Consider the following sentences:

  1. If it rains in California, everybody always gets gloomy.
  2. If I touched Jimmy, he would burst into tears. Is it true that "it rains in California"? Yes. Is it true that "everybody always gets gloomy"? No. Therefore, sentence (1) is false.

    But of course that line of reasoning doesn't make sense. We have to understand the phrase "in California" as taking the entire sentence in its scope, just as we understand "everbody" as taking in Californians who experience rain, which is not at all what "everybody" means in a self-standing sentence. Sentence (1) is undoubtedly false, but not for the reason worked out from the truth-table for material implication.

    Is it true that "I touched Jimmy"? No. I wouldn't think of it. Is it true that "he would burst into tears"? I can't answer that, since a sentence with a conditional modal can't be evaluated on its own. Assuming, for the same of argument, that the second clause is either true or false, then sentence (2) is true. But we know, of course, that the truth of this sentence, as we usually understand it, cannot be determined in that way.

    The point is, of course, that the subtle ways in which we understand the actual conditional sentences that get used in everyday talk involve detailed consideration of the actual grammatical form of the sentences themselves.

    Types of Meanings of Conditional Sentences

    Eve Sweetser, in From Etymology to Pragmatics has classified conditional semantics according to the three domains she speaks of in that book, the content domain, the epistemic domain, and the speech act domain. Content-based conditionals are understood by relating the content of the two clauses to each other. A typical way in which content conditionals can be understood is for the "P" clause to identify a situation which causes or automatically results in the state of affairs signalled by the "Q" clause. This is the case for Epistemic conditionals are understood as expressions of the reasoning process. If the state of affairs represented by the "P" clause turns out to be true, then we are licensed to believe what we are told in the "Q" clause. Thus: And speech act conditionals are understood as pre-posing to a speech act a "P" clause that identifies the situation which got the speaker to provide the speech act. Thus: We will see, in comparing the verbal forms of conditional sentences, that some combinations can only have the epistemic interpretation, others can have either an epistemic or a content interpretation. I have not explored the formal conditions for being a speech-act conditional.

    Verbal Forms

    A major descriptive problem that grammarians have to face in dealing with English conditional sentences involves the complex system of compatibility relations between the two parts of a conditional sentence. That is, certain verbal forms occurring in the antecedent clause of a conditional sentence are compatible only with certain other verbal forms in the consequent clause. Some examples of compatible combinations are these:

    Some examples of incompatible (or at least difficult-to-contextualize) combinations are the following: What we need for this set of facts is some set of general principles according to which these acceptability judgments, and the accompanying interpretations, can get explained.

    The tools we need for stating these principles include the following:

    Describing the selection of verbal forms in English conditional sentences is made complex by the facts that some of the relevant categories are not identifiable with particular morphemes or particular individual grammatical notions, but with complexes of these. What this means is that we will have to give different names to forms that have the same, or almost the same, superficial appearance. Furthermore, in discussing the categories we need, it is necessary to keep in mind the difference between "Time" (which we take as a semantic notion) and "Tense" (a grammatical notion).

    The names of the verbal-form categories we will use are these:

    In general, "perfect aspect" and "progressive aspect" can coexist with most of these forms and contribute their own meanings. In other words, in describing a conditional antecedent, the form "if he has seen her" will be simply classified as "present" for present purposes.

    Epistemic Stance

    In the immediately following discussion we will combine conditional sentences with sentences having a temporal subordinate clause. We can distinguish three sorts of epistemic stance - positive, neutral, and negative - which will indicate the degree of the speaker's commitment to the actuality of the proposition expressed in a subordinate clause. In the case of positive epistemic stance, the speaker accepts the truth of the proposition expressed in the subordinate clause: Thus, in "when Pat opened the door, the dog escaped", the speaker accepts the idea that Pat did indeed open the door and asserts that at that time the dog escaped. In the case of neutral epistemic stance, the speaker takes no stand on the truth of the proposition expressed by the subordinate clause. Thus in, "If Pat left the door open, the dog undoubtedly escaped", the speaker does not know whether or not Pat left the door open, but asserts an unfortunate consequence of such a state of affairs. And in the case of negative epistemic stance, the speaker assumes that "P" is not true, where "P" is a proposition derivable from (and preserving the polarity of) the form of the antecedent clause. Thus, in "If Pat had left the door open, the dog would have escaped," we hear the sentence as revealing the speaker's belief that Pat did not leave the door open. In using the words "positive" and "negative" epistemic stance, rather than, say, "believes true" and "believes false", I have in mind the fact that we may be dealing with conceits rather than beliefs. And in the case of future-time expressions, such as the difference between "If she invites them, they'll go" and "If she invited them, they'd go", we will interpret the latter sentence not as expressing the speaker's belief that "they" won't get invited, but that - say - "other things being equal", they're not likely to get invited.

    It seems to me that there are three basic types of conditional sentences, from the point of view of Epistemic Stance. I can refer to these as Generic (in which the speaker accepts the existence of instances of P but is presenting the "conditional" as a general principle), Neutral (in which the speaker makes no commitment about the actuality of P), and Negative (in which the speaker doubts the actuality of P). The following tables will show the relationships between Epistemic Stance, "Time", and Verbal Form. Each cell in these tables names the form of the verbal expression that expresses the Epistemic Stance (the table), the Time (the column), and appearance as Antecedent or Consequence (the row). Any conditional sentence can be formed by choosing, from one of the tables, one cell from the upper column and one cell from the lower column. (There are some other constraints, to be noted below.)


    Neutral Epistemic Stance

    Negative Epistemic Stance

    Examples of Neutral-ES and Negative-ES conditionals, illustrating each formal possibility, follow:

    Neutral Epistemic Stance

    It should be noticed that there are different pragmatic purposes to conditional sentences, which we can think of as causative versus inferential. Those in which the time of the antecedent follows the time of the consequent are necessarily of the inferential type.

    Negative Epistemic Stance

    The upper left ("past subjunctive") corner of the Negative ES diagram has a special status, in that there is a variety of forms that can express it. The standard form is identical to the pluperfect: "If I hadn't opened it." But there is a general colloquial form "If I hadn't 've opened it" and there is a special American colloquial form "If I wouldn't have opened it." Thus:

    A very important fact to notice about this collection of alternatives, and their evaluations, is that it characterizes not only the past Neg-ES forms of conditional antecedents, but also other contexts with Neg-ES meanings.

    One such context is as the complement of the verb "wish". Wish is the only verb in English which accepts these forms in its complement. We find (with the same acceptability judgments):

    The verb wish is used not only for expressing past counterfactual wishes, but also for expressing present and future wishes. In the case of present- time wishes, we find the sentential complements of wish taking the same present-subjunctive form we found with present Neg-ES antecedents. Thus, in "I wish you lived closer to Berkeley", the past-tense form is used to express a wish about a present-time situation, and in "I wish she were here", the special form "were" (rather than "was") can be used.

    There is one observation that keeps us from concluding that the complements of wish are simply identical, in their formal requirements, with Neg-ES antecedents, and that has to do with the FUTURE form. The future Neg-ES antecedent form is the same as the past tense, but in the case of wish, we do not get "*I wish you introduced me to Louise tomorrow", but "I wish you would introduce me to Louise tomorrow." How are we going to account for the obligatory "would" in this clause? I propose that clausal complements of wish and the antecedents of Neg-ES conditonals are indeed constructed in accordance with the same principles, but so far we have left out one set of facts. When such a clause expresses the Interlocutors' Interest (or that of some other discourse-relevant individual), the future-time version is formed with the modal "would". Since "wish" necessarily expresses the speaker's interests, the construction with "would" is obligatory in that case.

    This means that we should be able to find cases of "would" in the Neg-ES antecedents of conditional sentences, and that such clauses should be taken as expressing one or both of the conversation participants' interests. That is, in fact, what we find.

    Consider first a comparison of cases where we learn from the consequent whether or not the speaker has a positive interest in the outcome.

    Both of these sentences are acceptable. We can infer from the first one that the speaker wants the addressee not to have this conversation, and from the second one that the conversation with the father is desired. But the grammatical form of the sentence does not express these judgments. But now let us look at the same sentences with would: The oddity of the first of these sentences is that the consequent seems to contradict the assumption suggested by the verb form in the antecedent, assuming that the speaker of the sentence does not want trouble.

    Having seen that there is a separate form for Neg-ES future antecedents revealing participant interests, we can now ask whether such a possibility also exists for Neutral-ES sentences. It appears there is, namely in the form of the modal "will". We noted earlier that FUTURE Neutral-ES antecedents use the simple present tense form, instead of the expected will-future; but we can find "will" in sentences exhibiting the participants' positive interests. Compare:

    The questioned sentences in the preceding set are all odd, since they suggest that the speaker wants it to rain, or wants the addressee to break a dish.

    In earlier work I suggested that the will...will form of a conditional sentence was dedicated to "negotiations" or "negotiated offers". supported by sentences like "If you'll wash the dishes, I'll dry" and "If it'll make you feel any better, I'll stay another day or two". But I think now that the explanation of these forms is more general, and that the "negotiation" aspect of the interpretation of these sentences is merely a by-product of the sentences' ability to express both participants' interests.

    There is a generalization to be captured here. We are now free to say that in future-time antecedents, the modal will is used, and that this form has its present-tense form will in the Neutral- ES case, the past-tense form would in the Negative- ES case. Hence:

    In the cases where the future antecedent expresses the interlocutors' interests, the form will is used, in each case: It is well known that the antecedent clauses of conditional sentences are - or are capable of being - "negative polarity contexts", but this is only when the sentence does not express the interlocutors' interest.

    Some linguistic forms are generally welcome in only positive (or "positive interest") sentences, e.g., "a little". Other expressions, e.g., "any" (in the relevant meaning), are generally welcome only in sentences expressing uncertainty or negative interest. Compare the following,

    In the former case, I invite you to come closer, and propose a reason why you should be interested in doing so. In the latter case, I discourage you from coming closer, and I propose a reason for you to want to do otherwise.

    If we were to examine the compatibility problems for antecedent and consequent verbal forms in English conditional sentences, mentioned at the beginning of this section, we will find that the ones which are possible are those that "fall out from" the combined principles governing tenses, epistemic stance, and interlocutor interests, and that the ones which are impossible cannot be derived from the patterns that such principles create.

    The Challenge

    What are the things that need to be explained in a theory of English conditional sentences?
    1. The P clause can appear before or after the Q clause.
    2. The Q clause can begin with "then" only when the P clause comes first.
    3. The relation between the P-clause and its relevant Q-clause appears to be one of long-distance dependencies, which makes it similar to the LI construction.
    4. But there's a contradiction here, since the "sealing" (or "island" phenomena that we observe in other instances of LI (in particular in respect to the so- called "WH-island")) doe not seem to hold in the case of conditional sentences.
    5. There are compatibility relations in the form of the verbal expressions in the two clauses, such that the form of the verbal expression in each clause depends on whether
      • the clause is P or Q
      • the clause is of tense past, present, or future
        or perhaps simply past vs. nonpast, in the negative cases?
      • the epistemic stance is neutral or negative
      • the event signalled by P is of positive interest to somebody
    6. In some cases the structural feature which is the formal reflection of some such combination of conditions is morphologically complex, and not in a way that lends itself to being understood as a single constituent. This is so, because we have regarded VPs with complex auxiliaries as right-branching structures, where each successive auxiliary is in construction with the entire remainder of the VP. That is, we are not free, willy nilly, to regard "would have" as a single unit, since the structure we have imposed on such sequences is, say, "[would [have [eaten it]]]" and not "[would have] [eaten it]"
      • (One wonders what this has to do with some observations of Joyce Tang Boyland (whose office is across the corridor from our classroom) about modal+have sequences functioning as single auxiliaries, in such colloquial sentences as "What would have you said?". See J. T. Boyland, "A corpus study of would + have + past-participle in English", to appear in Nigel Vincent, ed., Historical Linguistics, 1995.)
    7. Negative epistemic stance has to be understood in a special way in case the intended time is 'future'. When it is present or past, the meaning is essentially that of counterfactuality; but when it is future it appears to be a matter of other-things-being-equal likelihood. ("If she asks me, I'll aaccept" versus "If she asked me, I'd accept".)
    8. The person whose "positive interest" is in question for the positive polarity sentences is one or both interlocutors in a typical case, but it might also be the "individual" we've been referring to as prag, that is, the person from whose point of view something is being expressed, which by default will of course be the speaker or addressee.
    9. In our informal discussion of the two parts of a conditional sentence we have been free to use words like "antecedent" vs. "consequent", or even "subordinate clause" versus "main clause", but we need to do better than that in representing the construction that will be able to take care of all of this. We will in fact need some way of showing that the P clause has an "anchoring" function with respect to the Q clause, since it provides the conditions under which the interpretation of the Q clause is based. This might need to be integrated into our proposals for the architecture of our semantic representations, where we once proposed distinguishing "settings" from "scenes". The "settings" part included temporal settings, including tense and aspect, but also temporal, locational, and hypothetical adjuncts.
    10. There appear to be some features shared by temporal and conditional adjuncts. One of these is the use of present-tense for future meaning in the subordinate clause. Another is the possibility of a sort of "correlative" phrasing, with "then", when the subordinate clause precedes the main clause. Thus we have both
      • When he starts treating me like a friend, then I'll start showing him some respect.
      • If he does this, then I'll do that.
    11. Shall we arrange for the conditional construction to iterate? I would prefer to think of sentences like the following as instances of language play, and not as evidence of some natural process in English: "If we had some ham, we could make some ham and eggs, if we had some eggs."

    All of this means, of course, that when we write up the construction description, it will need to contain a number of primitive semantic/pragmatic notions that require interpretations that have not yet been completely pinned down. These will include our notions of anchoring, epistemic stance, prag's positive interest, and the notion of prag itself.

    The Construction

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