(Dis)allowing Infinitival Clause Complements

The other day, I misheard a friend, thinking she said (1):

1. * We'll disagree to do it.

I remember this because (1) is ungrammatical and I was immediately struck by its ungrammaticality. In actuality, when she had said (2):

2.   We'll just agree to do it.

Setting aside the fact that (1) and (2) would seem to mean entirely different things, why should (1) be ungrammatical? It doesn't seem to be just something about meaning, since (4) and (5), which are both grammatical, can be interpreted in a way that is practically synonymous (3):

3. The FDA (*dis)approved the new drug to potentially treat that disease.
4. The FDA (dis)approved of the new drug potentially treating that disease.
5. The FDA did (not) approve the new drug to potentially treat that disease.

So then the big question is, what kind of structure is available for (2) that isn't available for (1)?

The structure in (2) is actually a sub-type of one of the most well-studied phenomena in generative syntax: raising and (obligatory) control. Let's take a moment to birefly discuss them.

When a predicate (which can be a verb, adjective, preposition, noun, ...) has a non-finite clausal complement:

6. They were happy to grab some drinks.
7. It is about to fall.
8. Jack didn't persuade the intern to stay.
9. Liz might want it to rain.

In each of these cases in (6)-(9), the bolded word introduces the nonfinite clause as its complement. There are important differences between these. These differences have been given names: (6) is a Subject Control predicate, (7) is a Raising-to-Subject predicate, (8) is a Object Control predicate, and (9) is an Raising-to-Object (or ECM) predicate. The exact nature of these differences could span books, so let's not focus on them here. All that matters is that there are four types of these predicates.

Back to the original data at hand. We've seen the "dis-" prefix interfere with letting the verb "agree" tkae its nonfinite clause complement. That is, "agree" can function as a Subject Control predicate, but "disagree" cannot. We've answered our first question.

Now another question arises, do all types of raising/control pattern this way with the "dis-" prefix? The answer I have come to (after looking through the dictionary for words starting with "dis-" and then consulting with myself and other speakers to determine grammaticality), is a clear and resounding "yes".  (10)-(12) are clearly Subject Control, (11) is ambiguous between Subject Control and Raising-to-Subject, (13)-(14) are clearly Raising-to-Subject, (15)-(16) are clearly Object Control, (17)-(22) are clearly Raising-to-Object:

10.   We would not agree to go.
    * We would disagree to go.
11.   We would not like to go.
    * We would dislike to go.
12.   We would not qualify to go.
    * We would disqualify to go.
13.   We would not continue to go.
    * We would discontinue to go.
14.   We would not prove to go.
    * We would disprove to go.
15.   We would not encourage John to be in control.
    * We would discourage John to be in control.
16.   We would not empower John to be in control.
    * We would disempowered John to be in control.
17.   We would not trust John to be in control.
    * We would distrust John to be in control.
18.   We would not approve John to be in control.
    * We would disapprove John to be in control.
19.   We would not allow John to be in control.
    * We would disallow John to be in control.
20.   We would not believe John to be in control.
    * We would disbelieve John to be in control.
21.   We would not like John to be in control.
    * We would dislike John to be in control.
22.   We would not prove John to be in control.
    * We would disprove John to be in control.

Generalization: addition of the morpheme "dis-" to a verb removes its ability to perform as a raising/control verb and license a non-finite clause complement. This is entirely surprising,

If you believe morphemes like "dis" are added onto verbs outside of the syntax (e.g. in the lexicon, or some other morphological component), with no syntactic effect, then this is not only mysterious but underivable as a generalization. In other words, unless morphology interacts with syntax on a fundamental level (e.g. having the ability to license certain types of complements), this would have to be an accident. It doesn't seem like an accident.

If it's not an accident, from what does this pattern derive? It's hard for me to say at the moment, but it would be worth investigating what other syntactic properties a morpheme like "dis-" has. The first property that came to my attention is the following: the verb "disqualify" is obligatorily transitive (in the active voice) whereas "qualify" is obligatorily intransitive:

23. The judge disqualified *(the athlete).
24. The judge qualified (*the athlete).

Note that "(dis)qualify" was one of the verbs we saw before in (12), but we didn't consider what would happen if there were a potential object:

25. * We would not qualify John to go.
    * We would disqualify John to go.

Only "qualify" can act as a raising/control predicate, and only when it doesn't have an object. The other possibilities ("qualify" as a raising/control predicate with an object, and "disqualify" as a raising/control predicate with/without an object) are not possible.

Thus it might seem the syntactic property of licensing objects that "dis" interacts with, (23)-(24), is also related to the syntactic property of being a raising/control predicate, (12) & (25).


That's as much thinking as I've done on the topic, so I leave this to you, faithful reader, to ponder further.