The examples in (10) show that finite argument clauses come in at least two different forms, and that the choice between the two is largely depends on the matrix verb: the verbs zeggento say and vragento ask differ in that the former takes declarative clauses as its complement, while the latter takes interrogative clauses (i.e. yes/no or wh-questions) as its complement.

Although we occasionally find similar differences in the domain of nominal complementation (cf. Jan stelde een vraag/*antwoordJan asked a question versus Jan gaf een antwoord/*vraagJan gave an answer), this distinction is quite fundamental when it comes to complementation by finite clauses.

Since Grimshaw (1979), it has often been claimed that verbs are subcategorized for specific semantic types of complement clauses: embedded declarative clauses such as (10a) are of the “propositional” type and embedded questions are of the “interrogative” type. Grimshaw adds the type “wh-exclamative”, which is found in the examples in (11); the wh-phrases in these examples are not interrogative, but express high degree modification, just as in the exclamative main clauses in the primed examples. Note that there are a number of differences between the main clause and the embedded clause (e.g. concerning word order and the form of the wh-word) which we will ignore for the moment, but to which we will return in Section 11.3.4.

The fact that Grimshaw (1979) includes exclamatives suggests that the list of semantic types is open-ended in the sense that it would be possible to add more semantic types to it; so it seems desirable to restrict it by imposing principled constraints on the set of possible types. An attempt to do this can be found in Nye (2013), which proposes that complement clauses are selected on the basis of two binary features: [±wh] and [±factive]. These features characterize the four different constructions in (12), if we adopt the following definition of factivity: factivity refers to constructions with verbs that take a complement clause and in which the speaker presupposes the truth of a proposition expressed by that clause; cf. Kiparsky & Kiparsky (1970) in the interpretation of Broekhuis & Nye (2013). In the (a)-examples, the relevant proposition is expressed by the full complement clause, while in the (b)-examples, it is expressed by the non-wh part of the complement clause. For the two types of wh-questions, see also Groenendijk & Stokhof (1984:91ff), which defines the distinction in terms of pragmatic implicatures, i.e. the speaker’s presupposition instead of factivity. The sign ⊨ expresses that the truth of the following expression is entailed by the speaker.

The binary feature approach thus gives rise to the four construction types in Table 1, which now includes the new class of factive interrogatives illustrated in (12b').

	[-wh]	[+wh]
[-factive]	non-factive declarative (12a)	non-factive interrogative (12b)
[+factive]	factive declarative (12a')	factive interrogative (12b') wh-exclamative (11)

Another advantage of adopting the binary features [±wh] and [±factive] is that they allow us to explain why betreurento regret and wetento know impose different selection restrictions on their complement; the unacceptability of (13a) shows that the verb betreuren is only compatible with declarative clauses, whereas the acceptability of (13b) shows that weten is compatible with both declarative and interrogative clauses. This can be expressed by assuming that betreuren selects a [-wh, +factive] complement, but that weten imposes no restrictions on the [wh]-feature and thus simply selects a [+factive] complement. Providing a similar account in a non-ad hoc way seems more difficult if we adopt Grimshaw’s claim that verbs select semantic types like propositional, interrogative, or exclamative.

Note in passing that examples such as Ik betreur [wat je hier schrijft]I regret what you write here are not relevant in this context: the bracketed part is a free relative, so we are dealing with a nominal complement, not a complement clause.

Similarly, we could account for the fact that verbs like betwijfelento doubt in (14) can be combined with an embedded yes/no question, but not with an embedded wh-question, by assuming that betwijfelen selects a [-wh, -factive] complement (although this still leaves open why the embedded wh-question in (14) cannot be interpreted as non-factive). Again, a similar account is not possible under Grimshaw’s proposal, which claims that yes/no and wh-questions are of the same semantic type.

For completeness’ sake, it should be noted that a less fortunate aspect of a binary feature approach is that it does not account for the fact that factive verbs such as weten can also take yes/no questions: Jan weet (niet) of Marie morgen komtJan knows/does not know if Marie will come tomorrow, which can never be used to express a non-null proposition. This, as well as the problem noted for example (14), shows that the binary feature approach still needs some fine-tuning, but we leave this issue for future research.

The new class of [+factive, +wh] verbs does not seem to be restricted to factive interrogative constructions. If we assume that the feature [+wh] does not refer to a semantic feature, but to the formal (i.e. morphosyntactic) feature that wh-elements have in common and that allows them to undergo wh-movement, it may also include verbs that take exclamative complements; cf. the primeless examples in (11) above. Another construction that may be included, discussed in Nye (2013), is the one illustrated in (15a); the complement clause in this construction, which is especially found in narrative contexts, is introduced by the wh-word hoehow, but seems to be more or less semantically equivalent to the factive declarative dat-clause in (15b).

This section has shown that the semantic selection restrictions on finite complement clauses go beyond the dichotomies between (i) declarative and interrogative clauses, and (ii) yes/no and wh-questions that are usually found in descriptive grammars. In addition, we have shown that Nye’s (2013) binary-feature approach to the selection of complement clauses has certain advantages over Grimshaw’s (1979) approach based on semantic types.