HPSG without PS?
Richard Hudson, UCL
draft: August 1995
1. Introduction
There are two ways of thinking about the structure of a simple example such as Small babies cry:
in terms of phrases and the relations among their parts or in terms of the words and their
relationships to one another. At a very elementary level, the two approaches could be
diagrammed as in Fig. 1.
1
Fig. 1
The arrows will be explained shortly, but their main significance is to represent some kind of
`horizontal' word-word dependency, in contrast with the vertical relationships (following the
diagonal lines) in the first diagram. The approaches are based respectively on phrase-structure
(PS) and dependency-structure (DS). Both diagrams show that small babies combine to form a
phrase, but they show it in different ways. In the PS analysis the phrase itself is explicit, and the
word-word relationship is implicit: node 4 stands for the phrase, and the lines connect 1 and 2 to
4, but not to each other. For the DS analysis this balance is reversed: the arrow shows the
word-word relationship explicitly, but the resulting phrase is left implicit.
The purpose of this paper is to argue that syntactic analysis which includes DS should not use
PS as well; more precisely, I shall argue that this is true of most of syntax, in which constructions
are headed (and involve subordination), though I shall not try to argue the same for coordination.
(Indeed, I have argued elsewhere that coordination is precisely the one area of syntax where PS is
appropriate; see Hudson 1990: chapter 14.)
Virtually everyone accepts DS as part of syntax, even if not by name - the notion
`long-distance dependency' makes it explicit, but government, agreement, valency (alias
subcategorization), and selection are all horizontal dependency relationships, and all word order
rules seem to be expressible as dependencies. Similarly most theories now recognise
`grammatical relations' such as head, complement, adjunct and subject; although usually
expressed in terms of a function in the larger phrase, these can all be translated easily into types of
word-word dependency. As PS was originally defined by Chomsky, none of these notions was
available; so there really was no alternative to PS as a basis for syntactic analysis. But now that so
many dependency notions are available in most syntactic theories, it is time to ask whether we still
need the PS as well.
The question applies particularly urgently to Head-driven Phrase Structure Grammar
(HPSG; Pollard & Sag 1994) as can be seen from the simplified version of Pollard and Sag's
analysis of Kim gives Sandy Fido (p. 33) in Fig. 2.
2
Fig. 2
The most interesting thing about this diagram is the way the verb's structure cross-refers directly
to the nouns by means of the numbers [1], [2] and [3]. These cross-references are pure DS and
could be displayed equally well by means of dependency arcs. Almost equally interesting is the
way in which the verb shares its class-membership, indexed as [4], with the VP and S nodes. An
even simpler way to show this identity would be to collapse the nodes themselves into one. The
only contribution that the phrase nodes make is to record the word-word dependencies via their
`SUBCAT' slots: the top node records that the verb's subcategorization requirements have all
been met (hence the empty list for SUBCAT), while the VP node shows that it still lacks one
dependent, the subject. This separation of the subject from other dependents is the sole
independent contribution that PS makes in this diagram; but why is it needed? Pollard and Sag
argue persuasively (Chapter 6) against using the VP node in binding theory, they allow languages
with free constituent order to have flat, VP-less structures (40), and in any case HPSG recognises
separate functional slot for subjects (345). It is therefore important to compare the HPSG
diagram in Fig. 2 with its pure-DG equivalent in Fig. 3?
3
Fig. 3
What empirical difference is there between these two diagrams? What does Fig. 3 lose, if
anything, by not having a separate node for the sentence? Could an analysis like Fig. 3 even have
positive advantages over Fig. 2? Questions like these are hardly ever raised, less still taken
seriously. Pollard and Sag go further in this respect than most syntacticians by at least recognising
the need to justify PS:
But for all that a theory that successfully dispenses with a notion of surface constituent structure is
to be preferred (other things being equal, of course), the explanatory power of such a notion is
too great for many syntacticians to be willing to relinquish it. (p. 10)
Unfortunately they do not take the discussion further; for them the `explanatory power' of PS is
self-evident, as it no doubt is for most syntacticians. The evidence may be robust and
overwhelming, but it should be presented and debated. A reading of the rest of Pollard and Sag's
book yields very few examples of potential evidence. PS seems to play an essential role only in
the following areas of syntax:
 in adjunct recursion (55-6),
 in some kinds of subcategorization where S and VP have to be distinguished (125),
 in coordination (203),
 in the analysis of internally-headed relative clauses, for which they suggest a non-headed
structure with N' dominating S (233).
Apart from coordination (where, as mentioned earlier, I agree that PS is needed) the PS-based
analysis is at least open to dispute, though the dispute may of course turn out in Pollard and Sag's
favour.
The question, then, is whether a theory such as HPSG which is so well-endowed with
machinery for handling dependencies really needs PS as well. My personal view is that this can
now be thrown away, having served its purpose as a kind of crutch in the development of
sophisticated and explicit theories of syntax; but whether or not this conclusion is correct, our
discipline will be all the stronger for having debated the question. The rest of the paper is a
contribution to this debate in which I present, as strongly as I can, the case for doing away with
PS. The basis for my case will not be simply that PS is redundant, but that it is positively harmful
because it prevents us from capturing valid generalisations. My main case will rest on the
solutions to two specific syntactic problems: the interaction of ordinary wh-fronting with
adverb-fronting as in 0, and the phenomenon in German and Dutch called `partial-VP fronting',
illustrated by 0.
(1) Tomorrow what shall we do?
(2)Blumen geben wird er seiner Frau.
Flowers give will he to-his wife. `He'll give his wife flowers.'
First, however, I must explain how a PS-free analysis might work.
2. Word Grammar
My aim as stated above is `to argue that syntactic analysis [of non-coordinate structures] which
includes DS should not use PS as well'. Clearly it is impossible to prove that one PS-free analysis
is better than all possible analyses that include PS, so the immediate goal is to compare two
specific published theories, one with PS and the other without it, in the hope of being able to
isolate this particular difference from other differences.
Fortunately there are two such theories: HPSG and Word Grammar (WG; see Hudson 1984,
1990, 1992, 1993, 1994, forthcoming; Fraser and Hudson 1992; Rosta 1994). Apart from the
presence of PS in HPSG and its absence from WG, the two theories are very similar:
 both are `head-driven' in the sense that constructions are sanctioned by information on the
head word;
 both include a rich semantic structure in parallel with the syntactic structure;
 both are monostratal;
 both are declarative;
 both make use of inheritance in generating structures;
 neither relies on tree geometry to distinguish grammatical functions;
 both include contextual information about the utterance event (e.g. the identities of speaker and
hearer) in the linguistic structure; and perhaps most important of all for present purposes,
 both allow `structure sharing', in which a single element fills more than one structural role.
Admittedly there are some theoretical differences as well:
 HPSG allows phonologically empty elements,
 HPSG distinguishes complements from one another by means of the ordered SUBCAT list
rather than by explicit labels such as `object'.
And not surprisingly there are disagreements in published accounts over the vocabulary of
analytical categories (e.g. Pollard and Sag's `specifier' and `marker') and over the analysis of
particular constructions (e.g. Hudson's analysis of determiners as pronouns and total rejection of
case for English; see Hudson 1990: 268ff, 230ff; 1995a). However these differences, both
theoretical and descriptive, are only indirectly related to the question about the status of PS, so we
can ignore them for present purposes.
One problem in comparing theories is to find a notation which does justice to both. The
standard notation for HPSG uses either attribute-value boxes-within-boxes or trees, both of
which are specific to PS, whereas DS structures are usually shown in WG by means of arrows
between words whose class-membership is shown separately. To help comparison we can start by
using a compromise notation which combines WG arrows with the HPSG unification-based
notation, so that the information supplied by the grammar (including the lexicon) will be a partial
description of the structures in which the word concerned may be used. For example, a noun
normally depends on another word, to which it is connected by an arrow, and (obviously) can be
used only at a node labelled `noun'; so Mary emerges from the grammar with the point of an
arrow (whose shaft will eventually connect it to the word on which it depends), and also with the
label `N' for `noun' (as well as `nN' for `naming noun', alias `proper noun'). In terms of
morphosyntactic features it is singular, i.e. `[sg]'. A simple way of showing this information is by
an entry like 0:
(3) 
Mary
N, nN
[sg]
For some words the grammar supplies a little more information. For example, deeply must be an
adjunct (abbreviated to `a') of whatever word it depends on, and he must be subject (`s') of a
tensed (`[td]') verb (which typically follows it).
(4) -a
deeply
Av
(5) he sN, pN
V
[td]
For a slightly more interesting word consider loves. As in HPSG this is supplied with a valency
consisting of a singular subject and any kind of noun as object. These requirements will
eventually be instantiated by dependencies to some other word, which we show by a labelled
dependency arrow. The English word-order rules fix their (default) positions, hence their
positions to the left and right of loves in the entry. Unlike the previous examples, loves can be the
`root' of the whole sentence, so it does not need to depend on anotehr word (though it may
depend on one, in which case it is the root of a subordinate clause); this is shown by the brackets
above the top arrow.
(6)
()

N s- loves -o N
[sg]
V
Putting these four entries together generates the structure for He loves Mary deeply in Fig. 4.
4
Fig. 4
Word order is handled, as in HPSG, by means of separate `linear precedence' statements.
Some apply to very general patterns, the most general of all being the combination of any word
with its `anchor' (the word on which it depends1). By default the anchor comes first in English,
though this default may be overridden by increasingly specific patterns. At the extreme of
1The
word anchor has not been used before in this sense, so far
as I am aware. The normal term in dependency analysis is either head
or regent, and I have always used head in my own work. However it
has caused a great deal of confusion for readers familiar with PS
uses of the same term. For example, in a PP such as with great care,
the `head' of great care is care for PS but with in DS. (More
precisely, with is the head of care, but the looser terminology is
tempting.) This confusion is a potentially serious problem and best
avoided. In any case, the notion `head' isn't very helpful as a
metaphor for word-word dependencies. Regent is tied to complements
and subjects which are `governed' by the word on which they depend,
so it brings false expectations for adjuncts. The metaphor behind
the word anchor is that the sentence-root is a fixed, firm, `anchor'
for the words which depend on it, each of which then acts as an anchor
for the words that depend on it, and so on recursively along each
chain of dependencies.
specificity are combinations of specific lexical items, which we can illustrate with the adverb
deeply. Normally this follows a verbal anchor as in 0-0, but it can precede the verb resent as in 0:
(7) I love her deeply
*I deeply love her.
(8) I slept deeply.
*I deeply slept.
(9) We looked deeply into each other's eyes.
*We deeply looked into each other's eyes.
(10)I resent the suggestion deeply.
I deeply resent the suggestion.
This idiosyncrasy can be shown by a special lexical entry for the sequence deeply resent,
supplementing the normal entry:
(11)
()

deeply a- resent -o N
Av
V
This example illustrates an important general characteristic of WG, which it again shares with
HPSG. Default inheritance and unification allow complex and specific entries to be composed
on the basis of much more general entries, with the consequence that there is no clear division
between `the lexicon' and `the grammar'. In WG the basic units of grammatical description are
in fact elementary propositions such as those in 0.
(12) resent is a verb.
resent has an object.
The object of a verb is a noun.
A word's anchor is obligatory.
A verb's anchor is optional.
A word follows its anchor.
deeply is an adverb.
An adverb may depend on a verb.
deeply may both depend on resent and precede it.
Only the last of these propositions is specific to the sequence deeply resent; but all the rest are
available in the grammar, and when applied to this sequence they generate the more complex
structure in 0.
Even at this elementary stage of explanation we can illustrate one of the positive disadvantages
of PS. In a PS-based analysis, deeply is the head of an adverb-phrase and resent is the head of a
verb-phrase, so the combination is in fact not a combination of words, but of phrases. In a
tree-structure, the two words are likely to be separated by at least one AP and two VP nodes.
These cannot simply be ignored in a lexical entry, because they are part of the definition of the
relationship between the words. In contrast, a pure-DS analysis shows the words themselves as
directly related to each other.
A similar problem arises with lexically selected prepositions such as the with required by cope
or the on after depend, which can be handled very simply and directly in WG (with `c' standing
for `complement').
(13)( )

cope -c with
V
P
In contrast, PS imposes a PP node between the verb and the preposition, so the only sister node
available for subcategorization by the verb is labelled simply PP; but cope does not simply take a
PP, it takes one headed by with. Pollard and Sag discuss the fact that regard lexically selects a PP
headed by as, but their suggestion that the relevant phrases could be identified by the feature [+/AS] (ibid: 110) is hard to take seriously. Similarly, stop requires a subordinate verb to be a
present participle, which can easily be expressed in a DS entry as a restriction imposed directly by
one word on the other:
(14) ( )

stop -c V
V
[prpt]
But if PS is available the first verb's sister is the VP headed by the participle, so the latter's
inflectional features have to be projected up to the phrasal node.
The problem in each case is that the phrase node is a positive hindrance to satisfactory
analysis. The problems created can of course be solved by projecting the head word's features
onto the phrase; but the PS is part of the problem, not of the solution.
3. Structure sharing and (dis)continuity
As mentioned earlier, perhaps the most important characteristic of HPSG and WG is the notion
of `structure sharing'. (`It is not going too far to say that in HPSG structure sharing is the central
explanatory mechanism ...', Pollard and Sag 1994:19) In both theories virtually all the major
complexities of syntactic structure require some kind of structure sharing. We start with a simple
example of subject-to-subject raising, which I shall assume needs no justification. The entry for
(intransitive) stop shows the raising as structure sharing whereby the two verbs share the same
subject:
(15)
()

N s- stop -c V
___ s
_/[prpt]
The sharing appears in sentence structure as two dependencies converging on the same word as
in the two diagrams of Fig. 5. The second diagram shows the recursive application of raising
where stop is combined with another raising verb, the auxiliary have.
5
Fig. 5
Structures such as this are a major innovation in dependency theory (as they once were in PS
theory) because they disrupt the normally simple relationship among dependencies, phrases and
linear order. If we assume that all the words which depend (directly or indirectly) on a single word
constitute a phrase, it remains true that phrases are normally continuous, i.e. not interrupted.
Normally an infringement of this generalization leads to ungrammaticality. For example, what
happens if we combine the following entries?
(16)-a after -c N
P
(17) 
parties
N
[pl]
(18)big a- N
A
The ordering restrictions on after and big require parties to follow both these words, but nothing
in the entries restricts the relative order of after and big; and yet after big parties is fine while *big
after parties (with big depending on parties) is totally ungrammatical. The obvious explanation
is that big parties is a phrase, so it must be continuous - i.e. it must not be split by a word, such as
with, which is not part of the phrase.
Traditionally PS-based theories have assumed that phrases should be equivalent to a
bracketing of the string of words, which means that discontinuous phrases are ruled out a priori
as a fundamental impossibility - a discontinuous phrase simply cannot be separated by brackets
from the rest of the sentence, because any brackets round the whole phrase must also include the
interruption. Admittedly alternative views of PS have been proposed in which discontinuity is
possible (McCawley 1982), and indeed the same is true of any PS-based theory (such as HPSG)
which admits structure sharing. But if discontinuous structures are admitted in principle, what
then excludes strings like *big after parties? The question seems trivially easy to answer from an
HPSG perspective: discontinuity is only permitted when it is caused by structure sharing, and
structure sharing is only permitted when it is explicitly sanctioned in the grammar. Structure
sharing removes a single element from one constituent and makes it act as part of another
(higher) constituent. For example, subject-raising causes discontinuity by locating the lower
clause's subject in a named place (subject) in the higher clause; but since the grammar says this
structure sharing is ok, it is ok. In contrast, there is no structure sharing pattern which allows big
to move away from parties, so discontinuity is not ok.
What will turn out to be a weakness in this answer is that the grammar has to stipulate each
structure sharing possibility. In most cases this is no problem but the problem data that we
consider below will show that more flexibility is needed. There is an alternative which is much
more obviously compatible with DS than with PS, and which will play a crucial part in the later
discussion; so to the extent that the explanation works it will count as evidence against PS. The
alternative is to ask what the essential difference is between the structures of It stopped raining,
where the discontinuous phrase it ... raining is grammatical, and of *big after parties, with the
illegal *big ... parties - apart from the fact that one is allowed and the other isn't. The difference is
that all the words in It stopped raining are held together by one continuous phrase (the whole
sentence). It has a legitimate place in the sentence thanks to its dependency on stopped, whereas
the only link between big and the rest of the sentence lies through the discontinuous phrase. In
other words, the grammatical sentence has a substructure which is free of discontinuities but
holds all the words together.
This observation provides the basis for a very general principle which controls discontinuity in
DS. For rather obvious reasons discontinuity always results in tangling arrows (provided we
consider the vertical arrow above the sentence root to be infinitely long).
The No-tangling Principle
A string of words is not grammatical unless its dependency structure includes a substructure in
which:
a. there is a single `root' word,
b. every other word depends either directly or indirectly on the root,
c. for each word, there is a single, minimal, chain of dependencies to the root,
d. no dependencies tangle.
We can call this tangle-free substructure the phrase's `surface structure' because this is the
structure which is responsible for surface word-order.
The only clause that needs any comment is (c). The point of this requirement is to force
`raising' while excluding `lowering'; so if a word has two anchors, one nearer to the root than the
other, the one to be included in the substructure must be the former. For example, the verb stop
shares its subject with its participle complement, but clause (c) guarantees that this shared word is
treated in surface structure as the subject of stop, not of the complement. This means that there is
no need to build this asymmetry into the lexical entry for stop, and indeed in true WG notation
(in contrast with the compromise used in 0) the entry is neutral regarding word order. The
relevant WG information on stop is actually a proposition2 which is equally compatible with
2Strictly
speaking this proposition is in turn derived, by
inheritance, from a simpler proposition about stop plus a general
proposition about the dependency-type `xcomp' (named after its
counterpart in LFG).
(i)
stop has an xcomp.
(ii) A verb's subject is also the subject of its xcomp.
either position for the shared subject:
(19)The subject of stop is also the subject of its complement.
In contrast, the HPSG analysis builds the raising into each relevant lexical entry and
structure-description, as a stipulation rather than as a general principle.
The No-tangling Principle will be crucial to the arguments in the rest of the paper. It expresses
a putative universal of syntax which limits the kinds of discontinuity that are permitted in any
language; but it also removes the need to stipulate how structure sharing affects surface word
order. This means, on the one hand, that we can simplify lexical entries as in 0, but much more
importantly it provides flexibility at just the points where it is needed. It will allow us to solve one
of our problems by providing two alternative surface structures for certain rather special
dependency structures; and the other problem will be solved by allowing an indefinite number of
raising slots controlled only by one general rule plus the No-tangling Principle.
In diagrams it is convenient to separate the surface structure from the other dependencies by
drawing it above the words (literally `on the surface', if the word-string defines `ground level'),
with all other dependencies added below. With this change the structure for It has stopped
raining is shown in Fig. 6.
6
Fig. 6
The effect of the No-tangling Principle is to guarantee that any example of discontinuity must
also involve structure sharing (with the possible exception of discontinuities caused by
parenthetical elements such as vocatives, which we shall simply ignore here). The converse does
not apply: not all examples of structure sharing lead to discontinuity. For example, both WG and
HPSG treat so-called `Exceptional Case-Marking' verbs as subject-to-object raisers, so the lower
verb's subject is also the higher verb's object, but this does not in itself lead to discontinuity as can
be seen from the structure in Fig. 7 for John expected Mary to come.
Proposition (ii) is a default which is overridden when the verb has
an object:
(iii)A transitive verb's object is also the subject of its xcomp.
7
Fig. 7
To prepare for the next section we need to illustrate two other kinds of discontinuous
structure: extraction, and extraposition from NP. The grammar entries responsible for extraction
are shown in 0, using the HPSG terminology for the three entries (Pollard & Sag 1994: 160). The
`Top' entry optionally allows any word to be attached to a finite verb (i.e. a tensed verb or an
imperative) by the dependency labelled `x+' (short for `extractee', but distinguished from `+x' for
`extraposee' by the `+' which marks the relative position of the anchor; in Hudson (1990) this
dependency is called `visitor'). This is the entry for topicalisation, as in Beans I like, and other
Top entries are needed for other types of extraction such as relative clauses and
tough-movement. The `Middle' entry allows the extractee of one word to be passed recursively
down a chain of dependents, and the `Bottom' entry allows the extractee dependency to be
`cashed' for some kind of complement relationship. Without this final trade-in the extractee has
no semantic role in the sentence, so extraction is impossible. Fig. 8 shows a sample structure in
which all three entries have applied.
(20) Extraction:
a. `Top'
word x+- V
[fin]
8
b. `Middle'
word x+- word -c word
__
x+
__/
c. `Bottom'
word x+,c- word
Fig. 8
Fig. 8 shows two discontinuous phrases, beans ... that you like and beans ... you like, both of
which are justified by the structure sharing of the `Middle' entry.
Why does the `extractee' relation override the word-order demands of the object
dependency? In this case the explanation involves default inheritance. In WG generalisations
about dependencies as well as those about word-classes apply only by default, i.e. unless
overridden by more specific requirements. As we shall see in section 6, dependencies, like
word-classes, are organised in an inheritance hierarchy with `dependent' as the most general type
and more specific types such as `subject' and `complement' below it. The word-order rule which
applies to objects is actually just one application of the very general anchor-first default rule for
English. The rule which positions extractees before their anchors is more specific, applying just
to extractees3.
(21)General:
A word follows its anchor.
Extractees only:
An extractee precedes its anchor.
The general principle of default inheritance ensures that the latter overrides the former.
Extraposition from NP is somewhat simpler as it involves only a single, non-recursive, entry
which generates examples like the following:
(22) Reports have emerged of widespread atrocities.
Someone came to see me who I hadn't seen for years.
(23) Extraposition from NP: V -+x word

/
N  _/
In this entry4 the vertical dependency arrow from V to N means that the N concerned may either
3In
Hudson 1990 I argued for a basic division of English
dependencies into `predependent' and `postdependent', with
`extractee' (alias `visitor') as a type of predependent. In that
analysis the word-order rule for extractees is in fact the one for
predependents in general. This is a side issue which is not relevant
to the present discussion.
4The
entry given here ignores what may turn out to be a serious
problem for the WG analysis of determiners as heads: an intervening
determiner does not affect extraposability, in contrast with other
intervening material which does. For example, (ii) is just as good
as (i) in spite of the determiner some which (according to WG) adds
an extra dependency between reports and are.
(i)
Reports have emerged of widespread atrocities.
(ii) Some reports have emerged of widespread atrocities.
In contrast, indisputable extra dependencies can make extraposition
harder (the so-called `Right-Roof Effect'), as in (iv) contrasting
with (iii).
precede or follow the `pivot' verb. This verb accepts one of the N's dependents as its own
`extraposee', labelled `+x'; more specifically, it accepts one of the N's `post-dependents' (i.e. one
of its complements or post-anchor adjuncts). Fig. 9 shows the structure generated for the first
example.
9
Fig. 9
Why does the structure sharing have the effect of moving the extraposee away from its first
anchor? Because raising is obligatory, so in the surface structure what counts is its extraposee
relation to the V, rather than its adjunct relation to the N.
The most important point to emerge from this discussion of structure sharing and
discontinuity in WG is that the consequences of structure sharing for word order are due to the
No-tangling Principle rather than to stipulated entries. We are now ready to consider our two
main empirical problems.
4. Preposed adverbials in English wh-questions
Adverbials (adjuncts of place, time, cause, etc.) can generally be preposed, giving examples like
the following which I take to be straightforwardly grammatical. The preposed adverbial phrases
are bracketed.
(24)[After that] I saw Mary.
[When he calls] tell him to ring back.
[For supper] we had ice-cream.
(iii) Reports of atrocities have emerged that have been denied.
(iv) ?Reports of atrocities have emerged that were committed by
government forces.
On the other hand it is possible that the constraint is due to
processing difficulties. This might explain the relative goodness
of examples like (v), where the intervening structure is
semantically rather `bland'.
(v) A collection of reports has been published of widespread
atrocities.
If there is a processing explanation, then the entry for
Extraposition should allow the `source' noun to depend only
indirectly on the pivot verb.
This preposing involves the same extraction process which we illustrated above, but the exact
mechanics are irrelevant. The main point is that the adverbial is a dependent of the first verb.
The structure for the last example is in Fig. 10, with the adverbial shown simply as `a' (for
`adjunct') of the verb.
10
Fig. 10
Adverbial preposing seems to apply freely to wh-interrogative sentences as well, as shown
by the following examples.
(25) [After that] who did you see?
[When he calls] what shall I say to him?
[For supper] who had ice-cream?
Only one order is possible: preposed adverbial followed by wh-pronoun.
(26) *Who [after that] did you see?
*What [when he calls] shall I say to him?
*Who [for supper] had ice-cream?
In fact, the preposed adverbial is in general the very first element in any sentence, as it also has to
precede the uninverted subjects in 0.
In a DS analysis there is no reason to doubt that the preposed adverb and the wh-pronoun are
both dependents of the first verb, as shown in Fig. 11.
11
Fig. 11
The most natural PS analysis would presumably treat the adverbial as an adjunct of the rest of the
sentence, as in Fig. 12.
12
Fig. 12
The crucial point about this structure is that whatever the label on the top node may be,
adjunction guarantees that it is identical to the one on the lower `sentence' node. Whichever kind
of analysis we use, then, there is no reason why the fronted adverbial should affect the
distribution of the whole clause.
Now we come to the problem. In the dependency analysis in Fig. 11, the root of the sentence
is clearly the tensed verb, had, and the two preceding elements, the adverbial and the
wh-pronoun, are simply dependents. We should therefore expect to be able to use the sentence
as a subordinate clause in a larger sentence such as 0.
(27) *For supper who had ice-cream is unclear.
(compare: Who had ice-cream for supper is unclear.)
But this is ungrammatical, although the corresponding sentence with the adverbial un-fronted is
fine. The same is true more generally of all our examples when embedded as subordinate
clauses.
(28) *I wonder [after that] who you saw.
*I wonder [when he calls] what I should say to him.
*I wonder [for supper] who had ice-cream.
Why?
It is easy to describe the problem informally: the wh-pronoun marks the absolute beginning of
the subordinate clause, in much the same way as a subordinator such as that, so the above
examples are bad for just the same reason as the following:
(29)*I know [after that] that you saw Mary.
*I know [when he calls] that I should tell him to ring back.
*I know [for supper] that we had ice-cream.
These sentences can all be mended, of course, by reversing the order of that and the adverbial,
which shows that adverbial fronting is possible in subordinate clauses (thus eliminating a
pragmatic explanation along the lines that fronting is pragmatically allowed only in main clauses):
(30)I know that [after that] you saw Mary.
I know that [when he calls] I should tell him to ring back.
I know that [for supper] we had ice-cream.
But if the wh-pronoun blocks pre-posing in the subordinate clause, why not in the main clause as
well? And why can't we mend the subordinate questions in the same way as the that clauses,
simply by reversing the order of the wh-pronoun and the adverbial?
(31)*I wonder who [after that] you saw.
*I wonder what [when he calls] I should say to him.
*I wonder who [for supper] had ice-cream.
For those attracted by a GB-style analysis, it is worth pointing out the problems raised by the data
just cited5. If the wh-pronoun was positioned before the `Comp' position of that, then a
wh-pronoun ought to be able to replace that before a preposed adverbial; so why is this not
possible 0? Similarly, if the preposed adverb was adjoined to CP and the wh-pronoun was moved
to the specifier of Comp, the combination adverbial + wh-pronoun should be just as possible in a
subordinate clause as in a main clause; but it is not 0. (It should be noticed, incidentally, that the
interrogative clause need not be a complement, as witness 0, so the solution does not lie in the
general ban on adjunction to complements suggested in Chomsky (1986: 6).)
The WG explanation requires a discussion of the structure of wh-questions. Take a very
simple example like Who came? Which word depends on the other? In the last paragraph we
took the verb to be the root of this sentence as in virtually every other sentence. The centrality of
the verb is one of the main tenets not only of dependency analysis but of virtually every other
modern analysis (including HPSG, in which a sentence is a kind of VP). After all, if who is the
subject of came, and subjects are dependents, then who certainly depends on came. But there is
also another set of facts about wh-questions which support the opposite analysis, with the verb
depending on the wh-pronoun (Hudson 1990:362ff):
 The verb (and therefore the rest of the clause) can be omitted, leaving just the wh-pronoun
(`sluicing'); e.g. I know someone came, but I don't know who.
 The wh-pronoun is the link between the clause and a higher verb; for example, wonder
subcategorizes for an interrogative clause, which means a clause introduced by an `interrogative
word' - a wh-pronoun, whether or if. In DS terms this means that in I wonder who came, who
depends on wonder, and came on who. It would be extremely difficult to write the necessary
rules if came depended directly on wonder: `a tensed verb which depends on wonder must itself
have a dependent interrogative word in first position'.
 The wh-pronoun seems to select the form of the following verb. After most pronouns this may
be either a tensed verb or TO plus infinitive, but one word is different: after why only a tensed
verb is permitted. (Compare I was wondering when/why we should do it with I was wondering
when/*why to do it.) Selection of this kind is typical of anchors in relation to complements, which
again suggests that the verb depends on the wh-pronoun.
 Semantically the verb (on behalf of the rest of the clause) modifies the wh-pronoun in much the
same way as a relative clause. For example, the question Who came? is asking for the identity of
the person that came, where that came clearly modifies person.
5These
facts are among the evidence against the existence of the
categories `Comp' and `complementizer' in Hudson 1995b.
In short, there is at least a good prima facie case for taking who as the anchor of came in Who
came?.
This descriptive conclusion is supported by similar conclusions from relative clauses and
possibly other areas of grammar as well, and leads to a very important theoretical conclusion: that
mutual dependency is possible. There are good reasons for taking who as a dependent of came,
but there are equally good reasons for taking came as a dependent of who. At this point DS and
PS part company severely. Although DS theory has traditionally set its face against mutual
dependence, this is just a matter of theoretical stipulation and could be abandoned under
pressure. For PS, as far as I can see, it is impossible to show mutual dependence in a monostratal
system, and even a transformational analysis would face severe problems. It remains to be seen
whether this pessimistic conclusion about PS is justified.
How does all this help with our problem? Because mutual dependency interacts with the
No-tangling Principle to give a free choice of surface structure. Either of the dependencies in
Who came? will satisfy the Principle, so either could be the (entire) surface structure. Thus there
are two ways in which we could draw the structure for Who came?, both shown in Fig. 13.
13
Fig. 13
This choice is not a syntactic ambiguity, but two alternative ways of satisfying the No-tangling
Principle. In this respect the diagramming system is misleading, so it should be remembered that
there is just a single syntactic structure for each sentence, in which each `surface structure' is
simply a sub-structure which satisfies the No-tangling Principle.
We now return to the examples with fronted adverbials. Take the sentence [For supper] who
had ice-cream? Which word is its root (i.e. the word on which the rest of the sentence depends)
- who or had? Fig. 11 took had as the root, which is the only correct answer. In this case who is
not a possible sentence-root because its arrow would tangle with the one linking for supper to
had, as can be seen from Fig. 14 which shows the choice which is now offered by the mutual
dependency of who and had.
14
Fig. 14
For the embedded example, however, even this option is impossible because who has to be taken
as the root of the subordinate clause. Fig. 15 shows the only possible structure for an example
without the offending adverbial, where the main point is the dependency between wonder and
who.
15
Fig. 15
Given this dependency, there is no way to avoid the tangling caused by the fronted adverbial,
which can be seen in Fig. 16.
16
Fig. 16
To summarise the argument, in who had ice-cream there are two ways to satisfy the
No-tangling Principle because both who and had make acceptable sentence-roots. If we add a
fronted adverbial such as for supper, this precludes who as a root; and embedding the clause
precludes had as root. It follows that if we combine the two patterns, neither word qualifies as a
possible root and the structure collapses completely. Hence the ungrammaticality of *I wonder
for supper who had ice-cream.
5. Partial verb-phrases in German and Dutch
The second empirical problem which will show the advantages of PS-free analysis is that German
and Dutch both allow movement of a `partial VP'. This phenomenon has received a good deal of
attention, especially within the HPSG community (e.g. Baker 1994, Haider 1990, Johnson 1986,
Nerbonne 1994, Uszkoreit 1987a, b, van Noord & Bouma 1995). Native speakers seem to agree
that German examples like the following (from Uszkoreit 1987a) are grammatical:
(32)[Den Brief zustecken] sollte der Kurier nachher
einem Spion.
[the letter to-slip]
was the courier afterwards to-a spy.
`The courier was to slip the letter afterwards to a spy.'
The problem is that on the one hand there is solid evidence that the bracketed material forms a
single phrase (because German grammar requires the finite verb, in this case sollte, to follow just
a single constituent), but on the other hand this would be less than a complete phrase in any
standard analysis of the un-fronted equivalent 0.
(33) Der Kurier
sollte nachher einem Spion den Brief zustecken.
The courier was afterwards to-a spy
the letter slip.
The facts are fairly simple. German allows the finite verb to follow any one of its own
dependents:
(34) Er isst einen Apfel jeden Tag.
He eats an apple every day.
Einen Apfel isst er jeden Tag.
Jeden Tag isst er einen Apfel.
If the finite verb is an auxiliary such as sollte in the earlier examples, the element before it may be
a dependent of the auxiliary's complement infinitive:
(35)Er sollte einen Apfel jeden Tag essen.
He was an apple every day
to-eat.
Einen Apfel sollte er jeden Tag essen.
Jeden Tag sollte er einen Apfel essen.
In each case the first element is an entire phrase; in general, phrases must be kept intact (as in
every other language).
The exception to this generalisation is that putative verb-phrases, called `partial VPs', may be
fronted as illustrated in 0 above, as well as in the following further permutations of the same
elements:
(36) [Zustecken] sollte der Kurier nachher den Brief einem Spion.
[Einem Spion zustecken] sollte der Kurier nachher den Brief.
[Nachher einem Spion zustecken] sollte der Kurier den Brief.
It is even possible for the syntactic subject to be included in the front-shifted group of words,
though this is only possible for very `inactive' subjects:
(37)[Ein wirklicher Fehler unterlaufen] war ihm noch nie.
A real error happened
was to-him yet never
`He had never yet made a real error.'
(38)[Eine Concorde gelandet] ist hier noch nie.6
A Concord landed
is here yet never.
(39) [Ein Witz erzählt] wurde.7
A joke told
was.
(40) [Ein solch schönes Geschenk gemacht] wurde mir noch nie.
A so beautiful present made
was to-me yet never.
In spite of the arguments in Baker (1994) it is hard to avoid the conclusion that the first phrase in
each of the bracketed groups really is the subject of both the verbs. Most obviously, it is in the
nominative case, which is normally found only in clear subjects (or predicative nominals). Slightly
more subtly, the last two examples have passive participles (erzählt, gemacht), which is evidence
that the nominative phrases have been raised from object to subject, and are therefore subjects
(Müller 1995).
Similar patterns are found in Dutch. The following examples are from van Noord & Bouma
1995.
(41)[Bezocht] heeft Jan dat congres nog nooit.
visited
has Jan that conference still never.
(42)[Bezoeken]
to-visit
zou Jan dat congres niet willen.
would Jan that conference not want.
(43)[Bezoeken willen] heeft Jan dat congres nooit.
to-visit wanted
has Jan that conference never.
The last example is particularly significant, illustrating as it does the recursive power of the
process behind the fronting. We shall return to it later but meanwhile we shall concentrate on
German.
These structures are a serious challenge for most theories of syntactic structure because the
fronted groups do not correspond to phrases that are recognised in the structure of a sentence
whose subordinate verb is in its normal position at the end of the sentence. In other words, they
involve movement of non-constituents. To take a simple example given earlier 0, it is possible to
front-shift essen, `to eat', along with any combination of einen Apfel, `an apple' and jeden Tag,
`every day'.
6Example
7This
from Andreas Kathol, via HPSG network.
example and the next are from Müller 1995.
(44)[Essen] sollte er jeden Tag einen Apfel.
[Einen Apfel essen] sollte er jeden Tag.
[Jeden Tag essen] sollte er einen Apfel.
[Jeden Tag einen Apfel essen] sollte er.
Admittedly German word order is sufficiently free for each fronted group to be able to constitute
the tail of a `normal' clause, but there is no evidence at all that they constitute a constituent when
they do. Moreover, to assume such phrases would be to abandon the idea that a verb and its
object form a phrase which excludes adjuncts; for example it would oblige us to recognise a
`verb-phrase' consisting of jeden Tag, a clear adjunct, and essen, but excluding the latter's object
einen Apfel: ... einen Apfel [jeden Tag essen]. Suitable grammars can be constructed (as
Uszkoreit 1987a demonstrates), but at great theoretical cost and with few descriptive insights.
Turning to DS-based analyses, if anything the challenge is even more serious for conventional
DS accounts than for PS-based ones, because the object and adjunct depend on the infinitive but
need not move with it, contrary to basic tenets of dependency grammar. The problem can be
seen in Fig. 17, a conventional DS analysis of Er sollte jeden Tag einen Apfel essen, `He should
eat an apple every day'.
17
Fig. 17
If essen is fronted, then it should take all its dependents with it because the alternative is either for
them to be left without anchors, or for the dependencies to tangle with others; and in either case
the No-tangling Principle is broken. These alternatives are illustrated in Fig. 18 for Essen sollte er
jeden Tag einen Apfel.
18
Fig. 18
Whereas the PS problem was that the fronted `phrases' implied a very clumsy and unrevealing
analysis of ordinary clauses, the DS problem is that a fronted verb which leaves its dependents
behind is simply impossible to analyse.
One way to solve these problems is to assume a flat, VP-less structure (which is no problem for
HPSG, and obligatory in any case for WG), plus optional raising dependencies controlled by the
No-tangling Principle. First, however, we must provide a little background grammar for German.
The verb-second phenomenon is easy to handle if we assume that each (non-interrogative) finite
verb has just one `extractee', again labelled `x+', which must be combined with one dependent of
that verb, or (recursively) of any non-finite verb which depends on it. (In many German dialects
extraction is limited to non-finite clauses.) For example, in Einen Apfel isst er jeden Tag, `An
apple eats he every day', einen (Apfel) is both the extractee and the object of isst; and similarly for
Einen Apfel sollte er jeden Tag essen, where einen is extractee of both sollte and essen, as well as
the latter's object. The structure is in Fig. 19.
19
Fig. 19
With extractees as an exception, a sentence-root verb precedes all its dependents; but this order
is reversed for other verbs - i.e. for any verbs which depend on another word.
(45)German/Dutch word order rules:
A sentence root precedes all its dependents.
Other verbs follow their dependents.
For example, in the last example the sentence-root verb sollte has three dependents: einen Apfel
(which as extractee precedes it), er and essen, both of which follow it; but essen follows both of its
un-extracted dependents, er and jeden (Tag).
Suppose we now, following Baker 1994, apply a `universal raising' rule to the extracted verbal
complement of any auxiliary verbs. This would raise any number of dependents of the
complement verb to serve also as a dependent of the higher auxiliary verb. Since raising is
obligatory, these dependents of the lower verb will be positioned as though dependents of the
higher verb, while their unraised co-dependents stick to the lower verb. This pattern involves a
new kind of raising. It is clearly not raising to subject, extraction or extraposition (the three types
of raising discussed so far), so we must invent a new name for the relationship which is involved.
The obvious name is `raisee', which we shall adopt with the abbreviation `r'.
(46) German/Dutch universal raising
Any number of dependents of an extracted verbal complement of an auxiliary verb A may also be
raisees of A.
This raising option is only available for a very restricted range of sentences, and does not lead
to ambiguity. It applies only to verbs which are both complements of an auxiliary verb and also
extracted, and when a dependent receives the extra `raisee' dependency this affects its position in
the sentence.
For example, if essen depends on the auxiliary sollte, then at one extreme we can raise every
single dependent into the surface structure so that they take their position after sollte: Essen sollte
er jeden Tag einen Apfel. At the other extreme, there could be no raisees at all so all the words
concerned line up before essen: Jeden Tag einen Apfel essen sollte er. And in between we could
raise, say, jeden Tag but not einen Apfel: Einen Apfel essen sollte er jeden Tag. Structures for the
three variants on our simple example are shown in Fig. 20 to 22.
20
Fig. 20
21
Fig. 21
22
Fig. 22
What about subjects that are front-shifted with the infinitive, as in 0 to 0? These are surprising
because one would expect them to be covered by ordinary subject-raising, which ought to apply
obligatorily. If Ein (Fehler), `an error', in 0 is the subject of the infinitive unterlaufen, and if war is
an auxiliary (as it obviously is), then the link between Ein Fehler and war ought to be in the
surface structure instead of the lower subject link. The solution must be more tentative, but it is
possible that this pattern is linked to the fact that German tensed verbs, unlike English ones, do
not have to have a subject. In the following classic examples there is no subject.
(47) Mich friert. `Me freezes', i.e. `I am cold'
Jetzt wird gearbeitet. `Now is worked', i.e. `Let's get down to work now'
If the subject slot is optional for the auxiliary verb, then raising to it must also be optional. In that
case, the problem disappears as the infinitive's subject has no dependency link to the main clause.
This analysis may also help to explain why the unraised subject must be inactive; subjectless
sentences seem only to be possible with inactive verbs (such as frieren) and passives.
As stated, the German Universal raising rule predicts that raising applies recursively across
auxiliary verbs. This may be true for German, but it is certainly true for Dutch to judge by the
example quoted earlier 0 and repeated here:
(48)[Bezoeken willen] heeft Jan dat congres nooit.
to-visit wanted
has Jan that conference never.
In this example one auxiliary (willen) depends on another (heeft), so any dependent of willen
may qualify also as a raisee of heeft, including dependents which are merely raisees of willen.
This applies specifically to dat (congres), which must be a raisee of heeft as well as raiseee of
willen and object of bezoeken.
Van Noord & Bouma (1995) show that the partial VP fronting which we have been discussing
is closely related to another construction found in Dutch and in some dialects of German:
cross-serial dependencies among final verbs. The facts are well known and much discussed since
Bresnan et al (1983). The following examples are from Van Noord & Bouma 1995.
(49)... dat Jan het boek wil lezen.
... that Jan the book wants to-read.
(50) ... dat Jan Marie het boek laat lezen.
`that Jan lets Mary read the book'
(51)... dat Jan Marie het boek wil laten lezen.
`that Jan wants to-let Mary read the book.
The examples are challenging because the verbs occur in the same order as their dependents,
which inevitably leads to tangling (`cross-serial') dependencies. However, universal raising may
offer a solution here as well. Let's assume that the dependent verbs are delayed by extraposition;
e.g. in 0 lezen could have preceded wil but is extraposed instead. This is an extra `raising'
dependency, labelled `+x', which allows us to define another class of verbs that depend on
auxiliaries. If universal raising were to apply to these verbs as well, any of their dependents could
become raisees of the auxiliary, which would avoid tangling in surface structure as shown in Figs.
23 to 25.
23
Fig. 23
24
Fig. 24
25
Fig. 25
It should be noticed that universal raising simply provides a background to other rules, and in
particular for the rules which allow verb extraposition. This explains why standard German does
not allow such examples, although it does have universal raising. The details of the rules are a
separate topic which is only indirectly relevant here. The main point is that a small extension of
Universal Raising may cover this construction as well. Moreover, this extension involves what
looks like a rather natural class of dependents, extractee and extraposee.
(52)German/Dutch universal raising (extended)
Any number of dependents of an extracted or extraposed verbal complement of an auxiliary verb
A may also be raisees of A.
This section has suggested that Dutch and German share the rule of Universal Raising, which
interacts with the No-tangling Principle to explain not only why `partial verb-phrases' can be
fronted but also why the expected order of verbs in final clusters can be reversed without
producing dependency chaos. The analysis relied crucially on the absence of any predetermined
raising structure, and more generally of any predetermined PS; raisee relationships are added
freely to the ordinary DS, generating patterns which are otherwise not possible. It is hard to see
how this kind of flexibility could be provided by a PS-based analysis which required a separate
entry for each structure-sharing pattern.
The price we have paid for the explanation is the introduction of a new dependency, `raisee',
whose sole function is to give extra flexibility in word order. Knowing that one word is the raisee
of another tells us nothing at all about the semantic relationship between them - indeed it almost
guarantees the absence of such a relationship; nor does it `carry' any other syntactic rules, such as
agreement or selection. This emptiness distinguishes the raisee dependency from most others,
but it is not unique. The next section takes this classification of dependencies a little further.
6. Dependencies and binding
One of the general themes running through this paper has been that structure sharing is the
correct way to handle departures from basic syntax. On this WG and HPSG are agreed.
However one rather fundamental point of difference is over the treatment of dependency
categories, the named attributes whose values may be words or phrases. HPSG has no unifying
concept or slot which covers them all - complements are in SUBCAT, subjects in SUBJ, and
adjuncts in ADJUNCT. In contrast, for WG they are all instances of the category `dependent'
which may be further subdivided into more or less general subcategories such as `complement'
(divided further into `object', `indirect object', and so on). This hierarchical classification of
dependencies not only allows generalisations across them, but encourages one to look for
similarities and differences among specific dependency types, so we can now survey the
dependencies which we have mentioned in this paper. Do any broad generalisations emerge
about any cluster of dependencies?
The examples of structure sharing have involved only a small number of dependency types:
subject, extractee, extraposee and raisee. These fall into two groups. Subject can be used without
any structure sharing (e.g. in any simple single-verb sentence), but the other three are never used
except in structure sharing. An extractee is never just an extractee, because this does not give
enough information to integrate the word into the sentence's semantic structure; it also has to
bear some `proper' dependency relation such as object. Similarly for extraposees and raisees.
Subjects are not alone in being able to occur either with or without structure sharing (i.e. subject
raising); if a subject-to-object raising analysis is right, then the same is also true at least of objects.
For most dependency types, however, structure sharing may not be possible, so we seem to have
the basis at least for a broad two-way classification of dependencies according to whether or not
sharing is their sole function. We shall arrive at an important generalisation about binding in
which PS plays no part at all, and indeed in which any notion of PS would simply get in the way.
Before we approach binding we can review the distinctive features of these three dependency
types which we have already discussed.
 As just mentioned, they are always involved in structure sharing.
 They are always `raisers' - i.e. when they combine with some other dependency type, they are
always the higher of the two.
 Therefore they are always part of surface structure (except when used recursively, in which case
the `lower' dependencies are excluded from surface structure).
 They never combine with each other, but only with dependencies of the other type (e.g. an
extractee of one word may also, recursively, be an extractee of another word, but it cannot be a
raisee of another word; in contrast, the subject of one word may be the object of another word).
In recognition of these similarities we can call extractees, extraposees and raisees `s-links', where
the `s-' recalls the s's of `surface structure' and `structure sharing'.
As van Noord & Bouma (1995) point out, the s-links extractee and raisee are irrelevant to
binding. (The same may be true of extraposition, but it is hard to construct critical examples.)
The following Dutch examples are from van Noord & Bouma's paper:
(53)dat Jani Pietj zichzelfj/*i ziet wassen
`that Jani sees Pietj wash himselfj/*i'
The binding possibilities are exactly the same in the Dutch example as in its English translation,
but in the Dutch example this is surprising given the dependency structures argued for above.
Universal raising has raised zichzelf into the top clause, as raisee of ziet, so it is a co-dependent of
Jan. In general a reflexive pronoun can be bound by the subject of its clause; in DS terms, it can
be bound by a co-dependent subject (Hudson 1984:173ff). Why then can't Piet bind zichzelf in
this example? Because the raisee dependency is invisible to binding. The next example confirms
this conclusion.
(54) dat Jani Pietj hemi/*j ziet wassen
`that Jani sees Pietj wash himi/*j'
Once again the raisee link between hem and ziet must be invisible to binding, because otherwise
hem would count as a co-dependent of Jan and should be non-coreferential, as it is for Piet.
The same is true for the extractee relationship in English as can be seen from the following
(rather stilted) examples.
(55)Himself/me/*him/*myself I think John admires.
The possibilities are exactly the same as in the un-extracted version:
(56)I think John admires himself/me/*him/*myself.
And yet there is no reason to doubt the existence of the extractee dependency between the
pronoun and think in 0, which makes the pronoun into a co-dependent of I. The only possible
conclusion is that this dependency, like the raisee one, is invisible to binding.
According to van Noord and Bouma, a recent development in HPSG theory (Iida et al 1994)
would have two separate lists of dependents: SUBCAT, for all complements, and ARG-S
(`argument-structure') just for those that are visible to binding. To make the contrast in this way is
to shift the explanatory focus away from tree geometry (and PS) to the classification of the
relationships themselves (and DS). Similarly, WG dependencies, as mentioned earlier, are
organised in an inheritance hierarchy from `dependent' at the top to specific grammatical
relations like `subject' and `object' at the bottom. This allows us to make the same distinction as
in HPSG, but to incorporate it into the overall classification of dependencies.
Fig. 27 presents a revised version of the dependency system in Hudson (1990: 208).
Dependents are of two kinds: s-links (explained above) and b-links, with b- to remind us that they
are visible to binding, that they are basic and that they are the bottom relationship in a structure
sharing pattern. This distinction is presumably universal, though there may be some languages
which have no s-links at all. (After all, `raisee' is part of German and Dutch but not of English,
and Japanese seems not to have any extraction.) A very different contrast applies to languages
with `mixed' word order (where head-final constructions exist alongside head-initial ones). These
seem to need a general distinction between `pre-dependent' and `post-dependent' (respectively,
dependents that precede and follow their anchor). In Fig. 26, unlike Hudson (1990), this
distinction is separate from the main system.
This diagram needs a little more explanation. The convention for showing inheritance (or
`isa') relations is also new (Hudson 1995c): a triangle has its (large) base against the larger, more
general, category, and its (small) apex linked to the subcategories or members. The diagram thus
allows multiple inheritance for dependencies; e.g. `subject' inherits both from `valent' and from
`pre-dependent'. The dotted lines apply to English but probably not to German and Dutch
(where relative order of verb complements is generally controlled by the German/Dutch word
order rules in 0); and `raisee' is bracketed because it is part of German and Dutch but not
English.
26
Fig. 26
The b-link/s-link distinction is similar to that between A- (`argument') and A'-positions in GB,
but does not involve tree-geometry and PS at all. Like the HPSG analysis of binding in terms of
obliqueness, it shows that not only can non-PS analyses `work', but they can also be expressed in
terms of natural and possibly universal categories.
7. Conclusions
A reasonable conclusion is that PS does not help to solve some of the most interesting problems,
and indeed probably makes them even harder to solve; as I put it earlier, the PS is part of the
problem, not of the solution. This case is particularly easy to argue when a lot of dependency
apparatus is already available and transformational solutions are unavailable, as in HPSG. The
main evidence for this conclusion involved our two empirical problems:
 The interaction between adverb-preposing, wh-movement and clause subordination in English
is quite easy to explain in terms of DS. The explanation hinged crucially on the assumption that
the wh-pronoun and the clause's root verb are mutually dependent, which would be difficult if not
impossible to express in a PS analysis.
 `Partial verb phrases' in German and Dutch are problematic for a PS analysis because they
involve phrases for which there is otherwise no evidence, and which in fact make normal
structures much harder to analyse. For a DS analysis all we need is a new relationship `raisee'
which can be added freely to any dependent just in those environments where partial VPs occur.
However, we also considered some other supporting evidence:
 Many lexical or grammatical facts involve restrictions imposed by one word on the head-word
in an accompanying phrase; e.g. a word may select a PP with a specific preposition, a VP whose
verb has a particular inflection, and so on. In these cases the particularities of the head-word itself
are directly visible to the controlling word in a DS analysis but not in a PS analysis, where they
have to be projected up onto the phrase node. This can be done, but the PS is the cause of the
problem.
 The peculiarities of s-links are hard to express in terms of PS, especially when they include the
German/Dutch `raisee' links but not subjects; at best PS is a harmless irrelevance. If
dependencies are available, they can be classified with `s-link' as one important subclass which
can be mentioned, as appropriate, in generalisations about raising, surface structure and binding.
What are the implications of this conclusion for syntactic theory in general, and for HPSG in
particular? It is hard to draw general conclusions beyond a plea for the issue to be given the
attention it deserves. For most syntacticians the need for PS is one of the few things that they are
really sure of, and which they might well describe as one of the pillars of modern syntactic theory.
As I have already observed, most modern syntacticians also accept a lot of dependency-based
concepts which were not recognised in the early days of PS theory, so it is high time for a general
review of the evidence for PS.
As far as HPSG is concerned, however, the conclusion is simple: the theory no longer needs
PS. Apart from the theory's name (why not HG?), the main thing which requires attention is the
`official' notation, where boxes-within-boxes can give way to boxes-beside-boxes. For example, to
return to the elementary example Kim gives Sandy Fido, instead of the HPSG analysis with VP
and S boxes to hold the word and phrase boxes together we could have the following, which in
every other respect preserves the insights of the HPSG analysis.
27
Fig. 27
The cross-referencing between boxes could be made more visible by adding dependency arcs,
but that really is just a matter of notation.
Apart from these notational changes, the main change needed in the theory is a revised
`subcategorization principle' (Pollard & Sag 1994:34). As it stands this principle reads as follows:
(57)SUBCATEGORIZATION PRINCIPLE (ORIGINAL VERSION)
In a headed phrase (i.e. a phrasal sign whose DTRS value is of sort head-struc), the SUBCAT
value of the head daughter is the concatenation of the phrase's SUBCAT list with the list (in
order of increasing obliqueness) of SYNSEM values of the complement daughters.
Without PS sisters (i.e. accompanying words) take over the role of the daughters:
(58) SUBCATEGORIZATION PRINCIPLE (REVISED VERSION)
The SUBCAT value of any word is a list (in order of increasing obliqueness) containing the
SYNSEM values of some of its sister words.
Various other revisions could also be considered but the main point that emerges from this paper
is that PS could be removed from current HPSG with considerable gains and little, if any, loss.
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POSTSCRIPT
Since writing this draft I've discovered more facts about German which undermine my proposed
analysis of fronted partial VPs which include the subject. According to three native speakers
(replying independently to a query on the HPSG network) the auxiliary verb agrees with the
fronted subject:
(59)Wirkliche Fehler unterlaufen waren ihm noch nie. `Real errors happened were ..'
This seems to show beyond doubt that Fehler really is the subject of the auxiliary as well as of the
infinitive. We therefore seem to have a clear example of subject lowering unless some clever
alternative can be found .... Any suggestions gratefully received! Notice that this has nothing to do
with PS, VP and so on - it's to do with the basic structure sharing mechanism.
Does anyone know of any other examples of lowering?