SIMILAR SITUATIONS

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SIMILAR SITUATIONS

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

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Caveat

• 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
  appreciated.

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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.

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

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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.

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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.

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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.

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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.

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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.

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Contrast set

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

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Contrast set contd

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

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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
  liars.
• We must specify in what respects two things are
  similar.

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Goodman on similarity contd

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

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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.

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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.

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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

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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.

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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.

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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.

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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?

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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.

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Counterpart theory

• The counterpart relation is a relation of
  similarity.
• 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.

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Counterpart theory contd

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

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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.

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Situations

• 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.

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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
  situation.

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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.

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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).

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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.

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Situations contd

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

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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).

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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.

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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
  polarity.
• Example NN4 and NN5 were playing cards during
  the game.

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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
  discussing?

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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.

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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
  surface.
• Tip of the iceberg the problem is only a small
  indication of a more serious trouble.

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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
  background.

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The iceberg analogy contd

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

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