Deep
Structure, Surface Structure and their Demise
(Note:
the following is very rough, informal; many distinctions have been elided for
the sake of clarity and space.)
The
enterprise begun by Chomsky in 1949 has gone through many changes, some
superficial, some profound. In recent years, Chomsky has highlighted what he
calls “virtual conceptual necessities”; these are properties any theory of
linguistic competence must reflect or accommodate:
(i)
A lexicon - a ‘list’ of exceptions.
(ii)
Combinatorial structure - lexical items must be combined.
(iii)
Interfaces - the combined structures must interface with ‘external’ components
which put the structures to ‘use’, minimally, ‘sound’ and ‘meaning’.
These
characteristics are the bare minimum required to account for the structure of
the language faculty - an aspect of
the mind/brain.
From
the earliest theories to the latest, three principal phenomena have animated
the generative enterprise:
(i)
Dissociation of sound and meaning
Roughly,
because sound is linear - along one dimension - the structure required to
encode it must be likewise linear, i.e., the items of the structure must be well-ordered in the mathematical sense.
On the other hand, the structure required to encode meaning must be at least
two-dimensional, perhaps three dimensional. Compare:
(i)
Bill likes himself
(ii)
Which pictures of himself did Bill like?
(ii)
Dislocation
Where
an item in a structure is phonologically spelt out, is not necessarily where it
is construed. Passives offer
a clear example; also see the ‘tough movement’ case below.
(iii)
Empty categories
Some
elements of structures are not spelt out, e.g., The boat was sunk to collect the insurance. The boat didn’t collect
the insurance, the sinkers did.
The
transformational map from Deep Structure to Surface Structure was an attempt to
make sense of these phenomena.
The
Early Years
The
theory of The Logical Structure of
Linguistic Theory (1955-56) and Syntactic
Structures (1957) did not appeal to either Deep Structure or Surface
Structure. The architecture proposed consisted of
(i)
a context-free rewrite base (essentially a Post system, demonstrably Turing
equivalent), inclusive of the lexicon; and
(ii)
a transformational component that takes P-markers - structures generated by the
base - as argument, and produces P-markers as value. Transformations are either
optional, or obligatory. A kernel
sentence is one whose structure is generated just by obligatory
transformations. All further transformations take such structures as argument.
The
architecture as a whole constitutes an algebra:
L = [L , f
, R1 ,…, Rm , l
, F
, w1
,…, wn]
(1)
L = set of primes (primitive
elements)
(2)
f
= concatenation
(3)
R1 ,…, Rm = set of classes/relations
defined over (1)-(2), where R1
is =
(4)
l
= set of constructed objects by (1)-(3)
(5)
F
= map to descriptive conditions
(6)
w1
,…, wn
= set of classes/relations defined over L and L¢,
L¢,…
Base:
(i) S t
NP + VP
(ii) VP t
Verb + NP
(iii) NP t Npsing, NPp
(iv) Npsing t
(T) + N + Â
(v) NPpt
T + N + S
(vi) T t the, few, every,…
(vii) N t Bill, Mary, man,…
(viii)
V t
kiss, love, kill,…
(ix) Aux t
C(M) (have + en) (be + ing)
(x) M t may, shall, will, can, must
(PM) S
NP
VP
Verb
NP
NPsing AUX V NPsing
Bill C may have en be
ing kiss Mary
Transformations
A
transformation takes an abstract phrase marker (not a sentence), as specified by a structural analysis, and maps it
onto another phrase marker. Thus, each transformation is fully specified by a structural analysis (SA) of the input
and a specification of the structural
change (SC).
A
base generated structure, such as the terminal string of PM, is not a sentence,
for it has no number/tense. There must, therefore, be an obligatory transformation:
Number transformation:
SA:
X - C - Y
SC:
C t
s, if X = Npsing
Â
in other contexts
past in any context
This
generates the sentences:
Bill
kisses Mary
Bill
kissed Mary
Bill
may kiss Mary
Bill
may have kissed Mary
Bill
may have been kissing Mary
Bill
will kiss Mary, etc.
Bill
has kissed Mary, etc.
Bill
is kissing Mary, etc.
Any
sentence represented by a structure which results from obligatory transformations
is a kernel sentence: a mono-clausal sentence
in the active.
There
are optional transformations. These take the structure of kernels as input, and
produce a non-base generated structure. Passive
is optional in this way.
Passive transformation:
SA:
NP - AUX - V - NP
SC:
X1 - X2 - X3 - X4 t
X4 - X2 + be + en -X3 - by - X1
Why
Transformations?
The
basic reason is that re-write grammars are inadequate. They merely ‘list’ the
structures available without explaining them. We can see this in numerous ways.
Take
the AUX rule:
Aux
t
C(M) (have + en) (be + ing)
This
tells us that HAVE introduces the perfect morphology en, and BE introduces the progressive morphology ing. So far so good, but it simply lists
this; it does not explain its curious distribution. In particular, while HAVE
introduces en, it is affixed to the
following ‘verblike’ element; similarly, ing
is introduced by BE, but is affixed to the following ‘verblike’ thing. In other
words, the dependency of the morphology is cross serial, but re-write grammars
can only represent serial relations, such as nesting:
have be en kiss ing
Further examples are abundant in the ‘felt
relations’ between, say, indicatives and interrogatives, actives and passives,
topicalisation, structural ambiguities, etc. Transformations can explain these
relations by taking the linear morphological order as generated from an
underlying structure.
Deep
Structure and Surface Structure
Where
does meaning fit in? A not uncommon thought is that Chomsky, at least at the
time of Syntactic Structures, wholly
ignored the issue of meaning. This is false. The confusion arose from a
misunderstanding of the so-called autonomy
thesis
(AT)
Semantic information is not required for the selection of a grammar, i.e., the
base and transformations are not derivable from semantic information.
As
far as we can tell, AT was as true then, as it is now. But it does not follow
that the syntax tells us nothing about semantics. The following claim suggests
itself:
(S-S)
The meaning of a sentence is determined by its underlying kernel and its transformational
history from the kernel. That is, a theory of meaning need only target the
kernels and the transformations.
Chomsky
said this was no more than a suggestion, which, if proposed in generality, would
face a number of problems. Still, the idea was developed into the Katz-Postal hypothesis (An Integrated Theory of Linguistic Descriptions,
1964), which Chomsky accepted in Aspects
(1965):
(K-P)
Transformations are semantically irrelevant, i.e., interpretation targets the
underlying kernel alone.
Assume
K-P is true. It follows that the meaning of a sentence must be wholly
determined by its kernel. Chomsky re-christened kernels deep structures, and derived phrase markers surface structures.
This provides the following model:
Deep
Structure Þ
Semantics
r
Transformations
Surface
Structure Þ
Sound
This
is the model assumed in Cartesian
Linguistics.
An
Example
Take
the sentence The Invisible God created
the visible world. Let its deep structure be as follows
(DS) S
NP VP
the
God S
created
NP VP
NP
God
is invisible the world S
NP VP
world is visible
The
structure captures the inferential relations from the single sentence to (i)
God is invisible; (ii) the world is visible; and (iii) God created the world.
Transformation
(i)
Substitute the relative pronouns who
and which for the respective nouns of
the embedded Ss (the incident propositions).
SA:
X - Y - Z, where X = Z
SC:
X1 - X2 - X3 - X4 t
X1 - wh - X3 - X4
This
gives us: The god, who is invisible,
created the world, which is visible.
(ii)
Delete the wh word and the copula in
both embedded Ss.
(iii)
Invert the remainder of the reduced clauses with the heads of their respective
dominating NPs.
This
gives us: The invisible God created the
visible world.
Properties
of deep structure (circa ‘66)
(i)
The interface with semantics.
a.
Subcategorization
b.
Selection restriction
(ii)
Universal.
(iii)
The output of a now recursive base.
(iv)
The site of lexical insertion, form a now independent lexicon.
Properties
of surface structure (circa ‘66)
(i)
The interface with sound.
(ii)
Variable.
(iii)
The output of the transformational component.
Changes
Since 1966
In
1966 was approximately the last time there was a consensus on the architecture
of the language faculty. Soon were to begin the so-called linguistic wars, which were to do with the status of deep
structure. Chomsky (Studies on Semantics
in Generative Grammar, 1972) was to reject the Katz-postal hypothesis and contend that surface structure
essentially contributed to meaning, in the form of, e.g., scope,
presupposition, focus, etc. Ironically, these were precisely the problems which
had stopped Chomsky proposing K-P in 1957. At the same time, the base was finally
dropped, to be replaced by X-bar geometry, which amounted to a new theory of
deep structure:
(i)
XP t
ZP X'
(ii)
X'* t
X' YP
(iii)
X' t
X0 YP
Where
ZP and YP are phrases, X0 is a lexical item, and XP is the
projection from the item. In terms of a sentence, ZP would be the subject, YP
the VP, and XP the inflectional projection which heads the whole structure. The
basic geometry fits any phrase whatsoever, permitting a radical minimization of
the base.
XP
ZP
X'
X0 YP
X-bar
theory was the corner stone of the so-called ‘government and binding’ approach
(Chomsky, Lectures on Government and
Binding, 1981), which differed from the Aspects
model in various ways, principally, deep structure (now called D-Structure) is
no longer the interface with semantics; a new level was introduced - LF - for
that purpose. Similarly, surface structure (= S-Structure) doesn’t interface
with sound; instead the level of PF is now the interface:
D-Structure
[X-bar schemata, theta assignment]
S-Structure
[BT, Case, Bounding theory]
A-P Ü PF LF Þ I-C
Minimalism
The
minimalist program (initiated in Chomsky, The
Minimalist Program, 1995) rejects D-Structure and S-Structure, to leave
just the two interface levels.
Minimalist
Architecture (Circa 1995)
[LEXICON]
[NUMERATION]
Merge/Move
Merge/Move
A-P Ü
PF *
[SPELL-OUT]
Move
LF Þ
I-C
The
levels of D-structure and S-Structure are dispensed within on two grounds.
(i)
Firstly, neither is an interface level. Effectively, then, both were posited
for internal reasons, to satisfy descriptive demands, not on the basis of virtual
conceptual necessity. On the assumption that the language faculty is perfect, all properties of the faculty
should follow from what is demanded of the interfaces. In this light, the
levels are departures from perfection.
(ii)
The information the levels are intended to encode can be encoded at the
interface or in the lexicon. Indeed, D-structure only problematically meets its
demands of theta-realisation. Consider ‘tough movement’ (Chomsky, 1981, p.309)
cases:
(1)
Bill is easy (for anyone) to please.
(cf.
It is easy (for anyone) to please Bill.)
The
matrix Bill cannot be inserted at
D-structure, for the position is not theta-governed, i.e., it doesn’t realise
an agent position. But nor can Bill be inserted as object of please and then move - via
transformation - to matrix position. But D-structure is where lexical insertion
is supposed to take place! Things get worse. Consider
(2) A man who is easy (for anyone) to please
is easy (for anyone) to convince.
One
might be persuaded to insert Bill
anywhere in the derivation, but it is certainly much
harder
to accept the lexical insertion of a man
who is easy (for anyone) to please, in the very same context where Bill creates a problem in (1). The very
same transformation that raises difficulties for the analysis has taken place
inside the subject in this instance.
When
Howard Lasnik raised this difficulty in Chomsky's class - so the anecdote goes -
Noam paused for an unusually long time, to then concede what Lasnik was asking
him to accept: the need for generalized
transformations. Of course, if the latter are part of the grammar, we can (in
minimalist terms) merge not just Bill, but in fact also a phrase of
arbitrary complexity, such as the (previously assembled) a man who is easy (for anyone) to
please. But to concede this point, is to reject D-structure, for the whole
purpose of that level of representation was to create a unified object to
express configurational relations prior to the occurrence of any
transformation.
In
the last few years, proposals have been advanced against the interface levels.
This, again, is a drive for perfection: levels, with their sui generis features, appear to be a departure from perfection. As
Chomsky writes:
The
principled elements of S0 are the conditions imposed on FL by the
systems with which it interacts. If language is to be useable at all, its
design must satisfy on “interface condition” IC… The goal is to determine just
what aspects of the structure and use of language are specific to the language
faculty, hence lacking principled explanation at this level.
[I]nitial conditions…
(i)
unexplained elements of S0
(ii)
IC (the principled part of S0)
(iii)
general properties
Principled
explanation, going beyond explanatory adequacy, keeps to (ii) and (iii). An
extremely strong minimalist thesis: (i) is empty.
¾
N. Chomsky, ‘Beyond Explanatory Adequacy’, unpublished.
Level-Free
Architecture
[LEXICON]
[NUMERATION]
Merge/Move
A-PÜ
·
Þ
I-C
Merge/Move
A-PÜ
·
Þ
I-C
Merge/Move
A-PÜ
·
Þ
I-C
…