1. Linguistic Theory
Lecture 11
Explanation

2. How do we explain things?
In lay terms an explanation answers the question why:
A: “Why are you carrying that large heavy suitcase?”
B: “I just bought a Japanese wrist watch”
A: “What’s that got to do with the suitcase?”
B: “The watch is Japanese but the batteries are Russian”.

3. In science, we also want to answer the question ‘why’
In science, we also want to answer the question ‘why’. But things are more difficult.
The reductionist problem:
If X explains Y, what explains X?
The only natural end to this would be to map everything back to the initial event (the big bang).
But we can’t do this – not enough evidence
Even if we could, we wouldn’t understand it and what’s the point of an explanation that you can’t understand?

4. Explanation in Linguistics
There are two ways that explanation comes into linguistics:
The normal one – what explains X?
A more technical one: given two theories how do we decide which one is best?

5. Levels of adequacy
For any set of data, there are an infinite possible grammars that capture the data
So how do we decide which one is the right one?

6. A demonstration of infinite possible grammars
Suppose a simple language with one word, “a”
The sentences of this language contain any number of instances of the word: a aa
aaa
aaaa
etc.

7. S  a S  Sa
This grammar will generate all and only all the sentences of this language
But so will:
S  a or S  a etc. S  aS S  Sa S  aS
Moreover so will:
S’  Sb (obligatory deletion rule) S  a Delete b at the end of a S  Sa sentence

8. All these grammars are distinct, but they all generate languages which have sentences made up of any number of ‘a’s
Which one is correct?
Chomsky (1965) proposed that different grammars attain different levels of adequacy:
observational adequacy
descriptive adequacy
explanatory adequacy = the highest

9. Observational adequacy:
a grammar which predicts all and only the grammatical sentences of a language (e.g. all of the grammars we previewed)
Descriptive adequacy:
Native speakers have intuitions about how sentences are structured:
S S S a a S a a
A grammar which conforms to these intuitions is descriptively adequate

10. Explanatory adequacy
A theory which sheds light on the logical problem of language acquisition is explanatorily adequate
two descriptively adequate theories of two different languages do not amount to an explanatorily adequate theory of language if they are very disparate
if both are possible human grammars, how would a child be able to learn any one?
a theory which contributes to a coherent notion of Universal Grammar therefore is one which has explanatory adequacy

11. Normal Explanation
Explanatory adequacy does not in itself guarantee explanation
it is just a method to use to distinguish between different grammars and to guide research
Explanation in linguistics comes through restriction
if grammatical principles are as complex as the data, then we have description
the simpler the grammar, the more explanation
simple does not necessarily mean easy to understand
it means structurally simpler
the fewer and more general the principles the simpler

12. Thus, suppose we have a grammar whose principles are in a one-to-one relation with linguistic phenomena:
Here the grammar is just as complex as the data and doesn’t help us understand it any better
But if two or more of these principles can be collapsed into a more general one, the grammar is simpler than the data P1 P2 P3
etc.
Phen1
Phen2
Phen3 P1 P3
etc.
Phen1
Phen2
Phen3

13. But this is a reductionist argument
We may be able to achieve more and more explanation
But we can never achieve the ultimate explanation
Perhaps this is enough
Perhaps not

14. The Minimalist Programme
Chomsky has argued (since 1990s) that we can achieve a greater degree of explanation
If the theory we produce is built on only absolutely necessary assumptions, then it cannot be reduced any further
What is absolutely necessary?
the set of assumptions that if they were not made, we wouldn’t have a theory of language

15. Suppose language is the mental system that links the part of the mind concerned with thinking and the part of the mind concerned with articulation (bodily movements)
thought
action
language

16. Suppose that is all there is
The two interfaces have requirements for language in order for it to do its job:
the products of the linguistic system must be interpretable in the relevant ways
Suppose that is all there is
the linguistic component consists of only the things that are required to enable interpretation by the conceptual and phonetic components
if anything else is needed to account for linguistic phenomena, this will require extra explanation (and we are back to where we started)

17. A Minimalist Demonstration
Why do things move?
In GB there were different reasons why things move:
to satisfy the Case Filter
to bind bound morphemes
semantic reasons
But if movement is part of the linguistic system it must have a reason motivated by the output conditions (conceptual and phonetic interpretation)

18. Language shows a number of phenomena which involve semantically interpretable features coupled with similar features which are not interpreted
e.g. verb agreement
features are interpretable on the subject (person, number, gender)
features a purely grammatical (uninterpretable) on the verb
Presumably, uninterpretable features are a problem at the output: what would the conceptual and phonetic components do with them?

19. The minimalist claim is that movement serves the purpose of ‘checking off’ uninterpretable features
uninterpretable features are generated in some position (e.g. on the verb)
the verb moves to be in a certain structural relation with the subject (specifier-head) where the features of one are checked against those of the other

20. IP DP3.s I’ I VP
If the features check, they are deleted and therefore not present at interpretation
If the features do not check they remain and cause the structure to be uninterpretable
Checking
V3.s

21. Phrase Structure in the Minimalist Programme
The output systems require a single structure to be formed from individual words for interpretation:
how can a sentence be interpreted either semantically or phonetically (order?) if unconnected words are presented
So it is necessary to have a structure building part of the grammar

22. Structure building proceeds as follows:
take two words
put them together to form a new object (= ‘merge’)
choose one to label the new object (= head)
loves
Mary
loves

23. Do we need any other principles?
The structure building process is a series of mergers which builds a structure step by step
Do we need any other principles?
how do we know which words to merge?
how do we know which one to select as head?
No other principle is needed other than that the structure that is built must be interpretable
if we merge two incompatible words, it will not be interpretable
if we choose the wrong head, it will not be interpretable
The system then distinguishes grammatical (interpretable) from ungrammatical (uninterpretable)