4.7 Comparison with other approaches 85
86 A syntactic procedure for displacement 4 remnant movement. Another one is the detailed treatment of the patterns occurring with multiple wh-displacement and the according explication of the feature checking mechanism. And yet another issue, presumably the most important one, concerns the meaning dimension. Brosziewski does not consider semantic issues beyond some basic mention; his work is syntactic in nature. The present thesis extends his work with a semantic dimension and thereby develops it into a full-fledged syntax/semantics interface.
In the remainder of the section, let us consider how my extension of Brosziews-ki’s approach to displacement compares with other approaches.
4.7.2 Movement-based approaches
One of the main points behind Brosziewski’s proposal, that I adopted as an important motivation, is the idea of not remembering whole derivations but preserving only those information that are necessary to establish non-local de-pendencies. This general idea can also be found in some recent movement-based approaches to displacement like phase theory (see Chomsky [21],[22]). In phase theory, only small chunks of structure are built; they are sent to phonology and semantics for interpretation as soon as possible. An expression that still has features to check can stay accessible by means of movement to the phase edge (usually the specifier of a designated head), which is not sent to the interfaces immediately but is kept until the next phase is finished.
It is possible to read expressions as we encountered them in this chapter in phase theoretic terms: Theaiin a complex expressionha1,ha2. . .han, xiiican be seen as being at the edge of a phase, while everything contained in xwas already sent to the interfaces.
This analogy, however, breaks down at second sight. The first important point with respect to which complex expressions differ from phases is that, although the extracted expressionsai are percolated through every step of the derivation, keeping them accessible does not require additional movement steps triggered by edge features (cf. Chomsky [23]) or local optimization (cf. Heck
& M¨uller [47]). It suffices that they are copied once, when they enter the derivation. After that, they simply stay at the edge of a complex expression, being pushed up higher and higher in the structure as more and more material is merged with the nucleus below them. The fact that no record of the forms at the edge are kept on the intervening nodes distinguishes my approach also from approaches relying on Slash feature percolation, for example GPSG [43], its successor HPSG [87], and proposals by Koster [67] and Neeleman & Koot [83].
With respect to structure expansion, my approach is actually very close to Tree Adjoining Grammar (see e.g. Joshi et al. [57], Kroch & Joshi [69], Kroch [68], and Frank [41]). In Tree Adjoining Grammar (TAG), all dependencies are established locally in elementary trees. These structures can then be expanded by inserting recursive structures between the extracted element and its corre-sponding gap – very much like in my approach additional material is merged
4.7 Comparison with other approaches 87 between the two parts of a split expression. However, TAG still employs a step of local movement in the initial elementary tree. My approach is much more radical in not employing any movement step at all, not even a local one.
The probably most important property of the forms that are kept at the edge is that they are kept in the order in which they were merged. This has an order preserving effect in the case of multiple wh-displacement: When the extracted expressions reach their target position, they are concatenated according to the order in which they appear at the edge, which reflects the order in which they would appear in base position. This offers a maximally simple account of order preservation, which is not possible without some stipulation in approaches relying on movement steps (including TAG). Moreover, it can be generalized to virtually all cases of multiple displacement that exhibit order preserving effects.
And finally, my approach sets itself apart in yet another way, the way of reducing the part of the structure that is accessible for syntactic operations.
Instead of restricting accessibility to a certain domain (verb shells and clauses, or every phrase XP) like in phase theory, the model of derivations proposed in this chapter restricts the available expressions to those that carry yet unchecked features – independently of how deep in the structure (or how long ago) they were introduced.
This idea can also be found in the very recent approach of Stroik [111], where only those expressions are accessible for further operations that are in-compatible with the currently active head (which largely coincides with having unchecked features). He employs a survival principle that copies those expres-sions into the numeration (or the workspace, if you want), from where they can then be imported back into the derivation. This exporting and re-importing applies at every step of the derivation, as long as the expression is compatible with the active head and can be incorporated into the structure. We can read our complex expressionsha1,ha2. . .han, xiiiin Stroik’s terms by assuming that the ai correspond to those expressions that were exported due to still having unsatisfied properties. The difference is that we do not need a mechanism for copying expressions into the numeration and later re-importing them into the derivation; rather our complex expressions are the workspace themselves.
4.7.3 Feature-enriched categorial grammar and Minimalist Grammars
As mentioned above, one of the characteristics of Brosziewski’s approach to displacement is the total lack of movement. This lack of movement also lies at the core of categorial grammars, a lexicalized grammar formalism based on di-rectional type logic. The assembly of form is determined by the types that are assigned to lexical expressions and by general inference rules for these types.
Instructions for the assembly of meaning, on the other hand, can simply be read off from syntactic derivations. The base grammar we developed in Chapter 3
88 A syntactic procedure for displacement 4 is, in fact, very similar to the base logic of a categorial grammar, to the point of sharing the limitation of not being able to capture non-local dependencies. One possibility to overcome this limitation in categorial grammars is the introduc-tion of structural reasoning controlled by unary modalities (corresponding to our features) that license the re-ordering of expressions and thereby determine which positions are accessible for semantic manipulation (e.g. for binding by an operator). These facilities allow to account for a range of cross-linguistic varia-tion, which was comprehensively shown for wh-question formation by Vermaat [119].
The main point in which my account for displacement differs from the cate-gorial approach (besides taking a generative and not a deductive perspective) is that categorial grammars inherently comprise a strict correspondence between syntax and semantics (due to the Curry-Howard correspondence, see e.g. Gi-rard et al. [44]), whereas I opt for loosening that tie. Which approach will prove more successful in accounting for natural language phenomena at the syntax/semantics interface is a matter of future research. I will point to some directions in the last chapter.
Loosening the tie between syntax and semantics in the present chapter meant that displacement is a purely syntactic process that neither receives a semantic interpretation nor builds structures that could feed semantics. Note that extraction was not even encoded in the syntactic types: An expression ha, xiinherits its type fromx. The fact that there is an element that still needs to check features is encoded only by keeping it at the edge. The edge thus plays a role very similar to a stack. In this respect, my approach converges with Stabler & Keenan’s recent version of Minimalist Grammars (see Stabler
& Keenan [107]). Minimalist Grammars are an algebraic formulation of the principles of Chomsky’s Minimalist Program [20], developed by Stabler [106]
and equiped with a semantic interpretation procedure by Kobele [65]. Stabler &
Keenan’s version interestingly dispenses with tree structures and instead resorts to lists of extracted expressions as the only information that is kept in the course of a derivation, very much like our edge of complex expressions. This makes it a very close relative of the approach developed in the present chapter, possibly they would even turn out to be largely equivalent. The difference, however, is that Stabler & Keenan employ flat lists of extracted expressions, while I introduced a recursive structure at the edge, allowing to extract expressions which itself contain extracted expressions. In Section 4.5 above, we saw that this additional structure can be exploited to capture remnant movement while at the same time obtaining Freezing effects.