SIMILAR SITUATIONS - PowerPoint PPT Presentation

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Title: SIMILAR SITUATIONS Author: Bilkent Last modified by: Bilkent Created Date: 4/11/2006 10:52:20 AM Document presentation format: On-screen Show – PowerPoint PPT presentation

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  • Varol Akman
  • Bilkent University, Ankara
  • April 14, 2006
  • Seminar at Bogaziçi University

  • Work-in-progress.
  • Almost nothing here that is original (with me). ?
  • Regard this as an attempt to review and evaluate
    the most promising ideas advanced so far.
  • Comments and suggestions are needed and

Plan of talk
  • AI research on analogy omitted.
  • Psychological (cogsci) research on similarity and
    analogy touched upon.
  • Goodman on similarity.
  • Lewis on similarity.
  • Situation theory.
  • Waismann on open texture.

  • There is nothing more basic to thought and
    language than our sense of similarity our
    sorting of things into kinds.
  • -W. V. Quine

Analogical transfer
  • How to cure an inoperable tumor without using a
    strong beam of radiation that would kill the
    surrounding flesh?
  • IDEAL SOLUTION Converge on the tumor with
    several weak beams of radiation.
  • PRIOR STORY Soldiers converging on a fort.

Analogical transfer contd
  • - 10 (originally)
  • - 30 (x3)
  • - 90 (x3)
  • A person encountering a new situation may not
    retrieve a prior experience that is available and
    may be useful.

Tverksys proposal
  • Object a is characterized by a set of features a.
  • s(a,b) denotes the similarity of a to b.
  • s(a,b) ?f(anb)
  • ?f(a\b)
  • ?f(b\a),
  • where ?,?,? 0.

Tverskys proposal contd
  • f reflects the salience (prominence) of the
    various features.
  • anb the features shared by a and b.
  • a\b the features of a that are not shared by b.
  • b\a the features of b that are not shared by a.

Tverskys proposal contd
  • This so-called contrast model expresses
    similarity between a and b as the weighted
    difference of the measures of their common and
    distinctive features.
  • Thus, we have a variety of similarity relations
    over the same set of objects.

Contrast set
  • Which country, Sweden or Hungary, most resembles
    Austria? (N.B. Relevant dimension of similarity
    not specified.)
  • Include Poland ? Sweden.
  • Include Norway ? Hungary.

Contrast set contd
  • Judgments of similarity appeal to features having
    a high classificatory significance.
  • Features of similarity ? Relevant contrast set ?
    Interests of participants.

Goodman on similarity
  • a is similar to b is a meaningless statement
    unless one can say in what respects.
  • NN1 is similar to NN2. ? They are both pathetic
  • We must specify in what respects two things are

Goodman on similarity contd
  • is similar to functions more like a blank to be
  • Similarity tends under analysis either to
    disappear entirely or to require for its
    explanation just what it intends to explain.

Goodman on similarity contd
  • The meaning is conveyed by the specific respects,
    not the general notion of similarity.
  • Example Moonbeams and melons are not very
    similar generally speaking.

Goodman on similarity contd
  • But if one is told that the Moonbeams have the
    property that the word begins with Melanies
    favorite letter, then one can generalize this
    property to melons with very high confidence.

Similar worlds
  • Lewis on counterfactuals.
  • If it were the case that A, then it would be the
    case that C.
  • A antecedent (usually assumed false)
  • C consequent

Similar worlds contd
  • In certain possible worlds where A holds (call
    them A-worlds), C holds also.
  • Question Which A-worlds should one consider?
  • Answer Those most similar, overall, to our world.

Similar worlds contd
  • Can there be worlds where A holds but everything
    else is just as it actually is?
  • Not really.
  • Hence, consider a world that differs from ours
    only as much as it must to permit A to hold.

Similar worlds contd
  • Thus, we need to consider a world closer to our
    world in similarity, all things considered, than
    any other A-world.
  • Analysis A ?? C is true at i if and only if C
    holds at the closest accessible A-world to i, if
    there is one.

Similar worlds contd
  • Comparative similarity is an imprecise notion but
    we frequently judge comparative similarity of
    complicated things.
  • To what extent are the philosophical writings of
    NN1 similar, overall, to those of NN2?

Similar worlds contd
  • Comparative overall similarity among possible
    worlds is taken as a primitive.
  • We balance off various similarities and
    dissimilarities according to the weights we
    attach to various respects of comparison.

Counterpart theory
  • The counterpart relation is a relation of
  • It is the resultant of similarities and
    dissimilarities in a multitude of respects,
    weighted by the significances of the various
    respects and by the degrees of the similarities.

Counterpart theory contd
  • Two respects of similarity and dissimilarity
    among counterparts of persons
  • Personhood and personal traits.
  • (ii) Bodyhood and bodily traits.

Counterpart theory contd
  • If we assign greater weight to (i), we obtain the
    personal counterpart relation.
  • If we assign greater weight to (ii), we get the
    bodily counterpart relation.

  • Parts of reality.
  • Not sets! Only in toy worlds (e.g., chess) can
    we describe them completely.
  • Perceived and stand in relations to each other.
  • Metaphysically and epistemologically prior.

How to individuate a situation
  • Direct perception (my immediate environment here)
  • Thinking (my last visit to Bosporus University)
  • Individuation (picking out) does not mean that
    one is able to give precise description of
    everything that is (and is not) going on in that

Vague objects
  • Are situations vague objects?
  • Bosporus University Campus Does it pick out a
    sharply bounded area of Istanbul?
  • Consider the claim Bosporus University Campus
    has an even number of trees.

Vague objects contd
  • This may be indeterminate (true only on some
    ways) if there are various different ways of
    drawing a spatial boundary to the Campus.
  • Note however that Bosporus University Campus is
    in Istanbul is true (true simpliciter).

Vague objects contd
  • QUESTION How can we talk about the similarity of
    two objects if they are both vague objects?
  • ANSWER We do this all the time. Basically, as
    long as we are not discussing matters that have
    to do with fuzzy spatio-temporal boundaries,
    there is no obvious complication.

Situations contd
  • Reality (one big situation) consists of
    situationsindividuals having properties and
    standing in relation at various spatiotemporal
  • One is always in situations. See them, cause them
    to come about, and have attitudes toward them.

Situations contd
  • Infons discrete items of information.
  • Denoted as
  • R,a_1,,a_n,p
  • where R is an n-place relation, a_1,,a_n are
    objects for the respective argument places of R,
    and p is the polarity (0 or 1).

A soccer game
  • NN1 and NN2 are having a conversation about a
    particular soccer game.
  • Usually, a confusion-free and informative
    discussion takes place.
  • And yet neither NN1 nor NN2 could list every item
    of information supported (see presently) by
    that game situation.

A soccer game contd
  • Take a particular infon ?.
  • The game situation may support ? (viz. the latter
    is made factual by the former), may support the
    converse of ?, or may leave it unassigned a
  • Example NN4 and NN5 were playing cards during
    the game.

A soccer game contd
  • NN3 interrupts NN1 and NN2 and asks What are
    you talking about?
  • Answer Last nights soccer game.
  • Were they talking about nothing?
  • Were they not sure about what it was they were

Open texture
  • We use a term in order to apply it to situations
    with which we are familiar.
  • Situations are rich (highly intensional) they
    cannot be described in their full detail.
  • Thus, infinitely many features remain implicit.

The iceberg analogy
  • Typically, 90 of an iceberg is under water, and
    that portion's shape can be difficult to guess
    from looking at what is visible above the
  • Tip of the iceberg the problem is only a small
    indication of a more serious trouble.

The iceberg analogy contd
  • When we describe an empirical situation, we make
    certain features explicit, but an indefinite
    number of other features remain implicit.
  • These implicit features constitute a hidden

The iceberg analogy contd
  • To apply a word to or in a novel situation, that
    situation must be similar to the source
  • But we cannot foresee in advance all the possible
    dimensions of similarity between the source
    situations and possible target situations.


This is the way the world endsNot with a bang
but a whimper.
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