There is, at first blush, syntactic similarity between constructions like (20)– (21) and those like (22)–(23).

(20) I want Mary to be a doctor

(21) She forced him to recite a poem

(22) I discovered him to be quite stupid

(23) We had assumed Mary to be a doctor

In fact (20)–(21) are examples of Modal (FOR) to complement constructions, while (22)–(23) are Judgement TO constructions. There are considerable semantic and syntactic differences, which fully justify the recognition of two varieties of complement clause both involving to.

Modal (FOR) TO complements relate to the subject of the complement clause becoming involved in the activity or state referred to by that clause, or to the potentiality of such involvement. Thus: I am hoping for John to go tomorrow, I wish (for) Mary to accompany me. The for may optionally be omitted after certain main verbs (with a semantic effect), the complement clause subject then becoming surface object to the main verb. Note that some verbs must retain for, e.g. hope, whereas some must omit it, e.g. force.

It is always possible—and often obligatory—for the subject to be omitted from a Modal (FOR) TO clause when it is coreferential with an NP in the main clause; for is then also omitted. If the complement clause is in subject function then its subject is omitted under coreferentiality with main clause object, e.g. (For Mary) to have to travel so much annoys John. If the complement clause is in object function then its subject may be omitted under coreferentiality with main clause subject, e.g. I don’t want (Mary) to travel so much. If the complement clause is in post-object slot with verbs of the ORDER subtype then its subject is omitted under coreferentiality with main clause object, e.g. I asked (the matron for) Mary to nurse me.

Many verbs that take a Modal (FOR) TO complement also accept a THAT complement clause. The meaning of the (FOR) TO construction is often similar to the meaning of the THAT construction when a Modal is included. Compare:

(24a) I wish that John would go

(24b) I wish (for) John to go

(25a) I decided that Mary should give the vote of thanks

(25b) I decided for Mary to give the vote of thanks

(26a) I decided that I would give the vote of thanks

(26b) I decided to give the vote of thanks

(27a) I expect that Mary will be appointed

(27b) I expect Mary to be appointed

(28a) I ordered that the flag should be raised

(28b) I ordered the flag to be raised

It seems here as if the complementizer to carries the same sort of semantic load as a Modal does in a THAT clause; this is why we refer to this variety of complement as ‘Modal’ (FOR) TO.

Some verbs which take both Modal (FOR) TO and THAT complements are seldom found without a Modal in the THAT clause. But others may freely include or omit a Modal. Alongside (25a) and (26a) we get:

(29) I decided that I was sick

There is no (FOR) TO correspondent of (29). We do get I decided to be sick, but this is most similar in meaning to I decided that I would be sick, which does include a Modal.

Although a Modal (FOR) TO construction will frequently have a similar meaning to a THAT construction with a Modal, they will never be exactly synonymous. Compare:

(30a) I remembered that I should lock the door (but then decided not to, as a way of asserting my distaste for authority)

(30b) I remembered to lock the door (but then Mary took the key and pushed it down a grating, so I couldn’t)

The THAT clause in (30a) simply records a fact, what my obligation was; it says nothing about my attitude to that obligation. A (FOR) TO complement, as in (30b), refers to the involvement in an activity of the subject of the complement clause (which is here coreferential with the subject of the main clause). The unmarked situation is that the subject would if at all possible become so involved, i.e. on hearing just I remembered to lock the door one would infer that the speaker did lock it. The subject would only not become involved if something outside their control intervened, as in the parenthesis added onto (30b).

A further pair of sentences exhibiting the delicate semantic contrast between THAT (with a Modal) and Modal (FOR) TO is:

(31a) John and Mary have decided that they will get married (e.g. when both have completed their professional qualifications)

(31b) John and Mary have decided to get married (e.g. next month)

Sentence (31a) announces an intention to get married; no date need yet have been mooted. But (31b) carries an implication that they have definite plans to marry in the foreseeable future.

Judgement to complements have a rather different meaning. The subject of the main clause verb ventures a judgement or opinion about the subject of the complement clause predicate (this semantic characterization will be expanded later). Most often the judgement is about some state or property which is either transitory, e.g. I noticed John to be asleep, or else a matter of opinion, e.g. They declared Fred to be insane. A Judgement TO construction is unlikely to be used to describe some permanent, objective property; thus, one would be unlikely to hear? He noticed her to be Chinese (only He noticed that she was Chinese). And most often the subject of the Judgement TO clause is human—?I believe that glass to be unbreakable sounds rather odd.

Whereas a Modal (FOR) TO complement can fill subject, object or post-object slot, a Judgement TO clause must immediately follow a transitive verb, effectively in object function. There is never any for, and the underlying complement clause subject is surface syntactic object of the main verb. This constituent is seldom coreferential with main clause subject (since it is relatively unusual to make judgements about oneself); when it is, it can never be omitted. Compare the Modal (FOR) TO construction I want Mary to win and, with optional coreferential omission, I want (myself) to win, with the Judgement TO constructions I consider Mary (to be) cleverer than Fred and I consider myself to be cleverer than Fred. Myself cannot be omitted from the last example.

A Judgement TO construction is frequently found with the main clause passivized, often so as to avoid specifying who is responsible for the judgement, e.g. He was declared to be insane. In fact, the verb say only takes a Judgement TO complement in the passive, e.g. Mary is said to be a good cook (but not *They say Mary to be a good cook).

The predicate of a Judgement TO clause most often begins with be. This can be the copula be, as in I reported John to be absent today; or passive be, as in I believed John to be beaten; or imperfective be, as in I suspect him to be hiding in the shrubbery, eavesdropping on what we are saying. Past tense can be shown—as in ING and Modal (FOR) TO complements—by the inclusion of have, e.g. I believed John to have been beaten. It is possible to have Judgement TO complements without be, as in (33b), but they are relatively rare. (There is a special kind of Judgement TO construction with the SEEM type, and here complements without be are commoner)

All verbs which take Judgement TO also accept a THAT complement clause, sometimes with a very similar meaning. Compare:

(32a) I know that Mary is clever

(32b) I know Mary to be clever

(33a) I know that Mary raced giraffes in Kenya

(33b) I know Mary to have raced giraffes in Kenya

Note that a Judgement TO complement corresponds semantically to a THAT clause without a Modal. It is of course possible to include a Modal in a THAT clause after know:

(34) I know that Mary may/must/should be clever

But there is then no corresponding Judgement TO construction. A TO clause cannot include a Modal and there is no means of coding the information shown by the Modal in (34) into a Judgement TO construction. (It is also relevant to note that a Judgement TO clause puts forward a specific assertion, and the inclusion of a Modal would be semantically incompatible with this.)

This is a major difference between the two varieties of TO complement. A Modal (FOR) TO clause frequently corresponds semantically to a THAT clause with a Modal, as in (24)–(28). If a Modal is not included in the THAT clause, as in (29), then there is no corresponding Modal (FOR) TO construction. In contrast, a Judgement TO clause corresponds to a THAT clause without a Modal, as in (32)–(33). Once a Modal is included in the THAT clause, as in (34), there is no corresponding Judgement to construction.

Many verbs take a Modal (FOR) TO complement in object slot and a fair number take a Judgement TO clause, but only a handful may occur with both. Those which do—remember, know and learn—never omit the for from a Modal (FOR) TO clause when the complement clause subject is included, so that there could be no difficulty in the listener spotting which type of complement is being used. In fact these verbs most often have the subject of a Modal (FOR) TO clause coreferential with main clause subject and then omitted, as in (37b).

(35a) I remembered that Mary was very smart

(35b) I remembered Mary to be very smart (Judgement to)

(36a) I remembered that Mary should sign the visitors’ book

(36b) I remembered for Mary to sign the visitors’ book (Modal (FOR) TO)

(37a) I remembered that I should sign the visitors’ book

(37b) I remembered to sign the visitors’ book (Reduced Modal (FOR) TO)

There is a further, rather special, kind of Modal (FOR) TO construction. For some, but not all, verbs that take a (FOR) TO clause in object or post-object slot there is a noun derived from the verb that can be head of the subject NP, with the original subject becoming the possessor within this NP; the main clause then has as its predicate head the copula be. Compare:

(38a) I had intended (for) us to have lunch on top of the mountain

(38b) My intention was for us to have lunch on top of the mountain

Such a post-copula Modal (FOR) TO clause cannot omit the for if the complement clause subject is retained. However, the complement clause subject frequently is coreferential with the original main clause subject (now possessor within the subject NP) and is then omitted, together with for. Thus:

(39a) I hope to be chosen as captain

(39b) My hope is to be chosen as captain

(40a) She prefers to go in the evening

(40b) Her preference is to go in the evening

This construction is available to some verbs from the WANTING type— wish, desire, crave/craving, long/longing, hope, need, intend/intention, plan, aim (but not want, mean, prepare)—and to at least prefer/preference from the LIKING type. Note that some of these verbs are unchanged in form when used as a noun, while others have a derived form.

Warn and instruct from the ORDER subtype take a post-object Modal (FOR) TO complement. They enter into a similar construction (with nouns warning and instruction) and here the original direct object is marked by preposition to, within the subject NP, e.g.

(41a) I instructed the hired hands to keep out of the paddock

(41b) My instruction to the hired hands was to keep out of the paddock

In English there are wider possibilities for adjectival modification of a noun than there are for adverbial modification of a verb. The (b) alternatives in (38)–(41) are likely to be used when such modification is desired. We might find my unwavering intention in (38b), my fondest hope in (39b), her firm preference in (40b) and my strict instruction in (41b). The corresponding adverbs either seem a little clumsy (strictly) or else have a different meaning (fondly, firmly), or are not really acceptable at all (*unwaveringly).