Words

1
Words Meaning

• An introduction

2
Words Meaning

• Words and meanings are linked, but they are not
  identical
• Your textbook gives three reasons why
• i.) The translation argument
• ii.) The imperfect mapping argument
• iii.) The elasticity argument
• iv.) The partial ignorance argument

3
Overview

• Intro to words and meanings
• Three classic theories of meaning
• What is meaning made of?
• 3 Feature theories Classical, Family
  Resemblance, Protype
• Can we have meaning without features?

4
The translation argument

• Many words that exist in other languages that do
  not have an equivalent word in English-
• i.e. 'schlep', to move a heavy and bulky item
  from one place to another.
• Since we have the meaning, but not the word, in
  English, a word cannot be identical to its
  meaning- we can get one without the other

5
The imperfect mapping argument

• If words were the same as meanings, then there
  would be one word for every meaning, and one
  meaning for every word.
• Of course, there is not some strings of letters
  or phonemes have multiple meanings (ambiguity),
  and some meanings have many words (synonymy).

6
The elasticity argument

• The meaning of a word is not a fixed thing but
  varies with its context of use.
• So 'a tall tale' is not the same thing as 'a tall
  man'.
• Since the meaning of a word is not simply a
  function of the word, it cannot be that a word
  and its meaning are identical.

7
The partial ignorance argument

• Many of us (especially scrabble players) can
  recognize words that we can't give the meanings
  of
• Dont we want to say that in that case the
  person knows the word, but not the meaning?
• And if we do, doesnt that mean that a word is
  something other than its meaning?

8
What is a word?

• Similar arguments apply to a words sound or
  visual representation
• Many of us know words that we cannot pronounce,
  or words that we cannot spell
• We may even know that a word exists for a
  meaning, but know neither its spelling or sound
• A word cannot be simply identified with any one
  of these aspects, although most words participate
  in all three aspects

9
Open and closed class words

• We want to make a very sharp distinction between
  two kinds of words
• Open class words Words that pick out a thing or
  an action or an abstract pattern (like 'peace' or
  'justice')
• Closed class words Words that serve a purpose
  in mediating between other words
• Closed class words are function words like
  articles '('the', 'a'), conjunctions ('and',
  'or', 'because'), prepositions ('on', 'under')
  etc. that serve to define the relationships
  between words or between their referents
• Closed class words serve a vital role to lose
  them (as in Broca's aphasia) is largely to lose
  the ability to communicate

10
Complications

• What about words like hey, um, or so?
• They dont mean anything (they have bleached
  semantics) but they are still useful for certain
  kinds of purposes.
• What about private invented words that have never
  been shared with anyone else? Should they count
  as words?

11
Intension/Extension

• We refer to a phrase's definition as its
  intension so the intension of a word like
  chair might be furniture specifically designed
  for sitting on
• we contrast this to the phrases extension the
  objects that fall under the intension- in this
  case, all chairs.
• These have to be kept separate for many reasons,
  most notably because knowledge of a phrases
  intension does not necessarily make its own
  extension obvious
• e.g. The people I ate dinner with last night
• Much philosophy of meaning hangs on this
  distinction

12
Three classic theories of meaning

• i.) Meaning as reference
• - Two problems
• ii.) Meaning as ideational
• iii.) Meaning as conventionality

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i.) Meaning as reference

• Early philosophy of language tried to build a
  definition of meaning from saying that the
  meaning of a word was identical to the subset of
  its intension to which it referred- so if I say
  'the chair you are sitting on' what I mean is the
  chair right there.
• This approach came from mathematics and logic
• Gottlob Freges predicate calculus is a form of
  logic that analyzes propositions into atomic and
  quantified statements
• These propositions, along with related axioms,
  formed a kind of calculus that related
  mathematics and logic (alas, unsuccessfully as
  Russell showed).
• Logical atomism Each symbol (word) had to stand
  for an object

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Problems

• There were many famous philosophical problems
  with this
• a.) The difficulty of fixing the referent of a
  word
• b.) Some words have no apparent referent

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a.) Fixing the referent of a word

• Consider the celestial body which is visible low
  on the horizon in the early hours of the morning
• One can perfectly understand and use this
  definition without understanding that its
  referent is identical to the referent of the word
  Venus- because Venus is in fact the morning
  star.
• You might even believe it was true that The
  morning star is not the planet Venus even though
  you know the reference of each term individually-
  and therefore of both terms
• Similarly many examples of a word's referent does
  not always allow us to fix meaning of the word,
  due to the failure of induction
• Quine's gavagai

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b.) Some words have no apparent referent

• Closed-class words or very abstract words or
  words which refer to non-existent entities
• Alexius Meinong Since meaningful things must
  refer, non-existent objects must exist in
  logical space
• Bertrand Russell Logic must no more admit a
  unicorn than zoology can.

17
Theory of descriptions

• Descriptions are not names, but logical
  syllogisms
• A logical syllogism can be sensible
  (well-defined) but false
• Thereby we can salvage expressions that refer to
  non-existent entities without having to postulate
  their existence
• In this view language obscures what is actual the
  case
• Later we shall see that Wittgenstein will have
  much to say about this, in two different but
  related ways

18
ii.) Meaning as ideational

• Perhaps word Venus does not refer to the
  celestial body itself, but to your own idea of
  the planet.
• There are two problems
• i.) If words refers to something in your head,
  then we have to say that the referent of a word
  must share the same properties as things in your
  head
• The word 'light' refers to something in your
  head, so it must be true that 'the word light
  refers to something that it is dark'- which is
  mad.
• ii.) Failure to keep public reference
• If you are talking about something inside you and
  I am talking about something inside me, then how
  do we ever agree on what we mean?
• Meaning must be fixed publicly in some way.

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ii.) Meaning as conventional

• Perhaps meaning is a public construction
• we keep reference public by the way we act- we
  debug our internal references by our actions
• If you have one view of what I mean by 'Venus'
  and I have another, then we will fix them when
  our behaviours collide in some way.
• One implication is that we can mean different
  things by words so long as our meaning doesn't
  have any practical effects that keep us out of
  synchrony with someone else with whom we cannot
  be de-synchronized

20
What is meaning made of?

• However meaning may be fixed, we still want to
  know what it is that is fixed.
• What is meaning made of? How it is organized?

21
Feature theories

• One common answer is that meaning is made of
  features (or dimensions)
• So a cat has features like 'is an animal', 'is a
  mammal', 'can be domesticated
• This is popular in AI, since it gives meaning a
  clear tree structure allowing for inheritance
• For example, if you know that a cat is a mammal,
  then you automatically know that it bears it
  young live, it suckles its young, it has fur
  etc. etc.

22
How do features combine?

• The 'classical view' says that a concept is
  defined by necessary and sufficient features-
  i.e. by some features that it must have (the
  necessary ones), and by a minimal set of features
  that are all it needs (the sufficient ones).
• This is a cold logical view, which assumes that
  there is a discernible, specifiable logic
  underlying not just 'hard' concepts like
  'triangle', but soft ones like love, peace, and
  justice too.

23
How do features combine?

• The 'family resemblance' view says that there is
  no necessary or jointly sufficient features, but
  there is a greater or lesser agreement of a
  concept with its set of possible features
• This allows us to say that an individual can be a
  more or less good exemplar of a concept- so, a
  robin is a better example of a bird (because it
  has more 'bird' features) than a penguin.
• It also allows us to allow things to degrade
  without changing category membership- so a canary
  is almost always yellow, but it doesn't have to
  cease being a canary if we paint it purple

24
Prototypes

• The best exemplar is a prototype
• Evidence shows that it has some psychological
  reality people will respond faster to the
  sentence 'a robin is a bird' than they will to 'a
  penguin is a bird'.
• There is evidence that even categories which are
  defined classically, with necessary and
  sufficient conditions, show family resemblance
  structure
• People systematically judge some numbers as being
  'more odd' than others (and respond faster to
  statements about them), even though the only
  requirement for oddness is not being divisible by
  2.
• Same for 'a mother is a woman' (faster) than
  'waitress is a woman' (slower)

25
How do features combine?

• The knowledge-based view is an extension of
  feature theories
• One problem with features is knowing where the
  end when do features stop having features so
  that the system can 'bottom out' and return an
  answer.
• In some cases this is obvious (i.e. when the
  search is on for a specific feature), but in
  others it is not
• How do we calculate when we have 'enough'
  features to make a judgment such as 'A penguin is
  a bird'.
• How do we build idiosyncratic feature sets like
  Things my grandmother never lived to see that I
  own?

26
How do features combine?

• Knowledge based approaches say that features are
  built in contexts of 'theories'- that concepts
  cohere based on a deeper coherence of
  explanations which those features together
• Of course, this opens up the same questions we
  are trying to answer, but at a different level
  what is a theory made up? What are its components?

27
Psychological essentialism

• One theory is Psychological essentialism
  people act as if things have essences that could
  be defined, and sometimes they know what those
  essences are
• So, we have a theory that says that water is made
  of 2 hydrogen atoms and 1 oxygen atom, and
  anything else- no matter how much it looks or
  acts like water- is not water.
• most of us accept this contra family resemblance
  theory, some features just are necessary

28
Psychological contextualism

• Psychological contexualism' says that theories
  of essentialism can change with context
• Some features just are necessary in some contexts
• We might accept artificial orange juice as orange
  juice if we were thirsty, but might want to argue
  in chemistry or philosophy class that a liquid
  containing no matter from oranges was not orange
  juice.

29
Meaning without features?

• Features are defined generally enough to be
  all-inclusive any difference may be defined as a
  feature
• Later we will see other approaches that define
  features in unexpected ways as vectors in
  co-occurrence space, or as undefinable variety
  i.e. maybe features have no features!