Semantics1 Week 2: Difference between revisions
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== Why it is too difficult to go directly from language to the world == | == Why it is too difficult to go directly from language to the world == | ||
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# ... is mapped to some expression from a formal language (here: predicate logic): '''like'''('''rob''','''john''') | # ... is mapped to some expression from a formal language (here: predicate logic): '''like'''('''rob''','''john''') | ||
# This logical expression is then interpreted with respect to our scenario/world: The formula '''like'''('''rob''','''john''') is true, because, in our scenario, Rob likes John. | # This logical expression is then interpreted with respect to our scenario/world: The formula '''like'''('''rob''','''john''') is true, because, in our scenario, Rob likes John. | ||
The following properties of natural language make it useful to use the intermediate step of a logical language: | |||
# The same expression can have different meanings (ambiguity). | |||
# Different expressions can have the same meaning (synonyms, paraphrases) | |||
Find examples for the above-mentioned properties (ambiguity, synonymy, paraphrases). | |||
= What we need in a formal model = | = What we need in a formal model = | ||
Revision as of 23:32, 21 April 2015
Additional material for the meeting of week 2, April 22, 2015.
Our literary scenario: Game of Thrones (TV series)
- Wikipedia site: http://en.wikipedia.org/wiki/Game_of_Thrones
Site on season 1: http://en.wikipedia.org/wiki/Game_of_Thrones_%28season_1%29 - Short summary of season 1 on youtube: https://www.youtube.com/watch?v=atxp6x3YreI
Our scenario and some preliminary thoughts
Getting into our literary scenario
Watch the trailer of Season 1 of Game of Thrones:
<mediaplayer>https://www.youtube.com/watch?v=YinJaXzgzqI</mediaplayer>
Having watched the video, which of the following statements are true in our scenario?
The meanings of some of these sentences are unrelated. What do you observe for the following sentence pairs?
Catelyn wants that her husband becomes the king's Hand. and Catelyn wants her husband to become the Hand of the king.
Check your answers
The two sentences are paraphrases of each other, i.e., in every situation, whever the first is true, so is the second.
There is a king. and There is no king.
Check your answers
The two sentences contradict each other. Whenever one is true, the other must be false.
Catelyn wants that her husband becomes the king's Hand. and There is a king.
Check your answers
Whoever utters the first sentence must also assume the truth of the second. (Technically, the second sentence is presupposed by the first, but this doesn't matter here.)
Why it is too difficult to go directly from language to the world
The following architecture is extremely useful when talking about semantics:
- A natural language expressions: Rob likes John.
- ... is mapped to some expression from a formal language (here: predicate logic): like(rob,john)
- This logical expression is then interpreted with respect to our scenario/world: The formula like(rob,john) is true, because, in our scenario, Rob likes John.
The following properties of natural language make it useful to use the intermediate step of a logical language:
- The same expression can have different meanings (ambiguity).
- Different expressions can have the same meaning (synonyms, paraphrases)
Find examples for the above-mentioned properties (ambiguity, synonymy, paraphrases).
What we need in a formal model
<mediaplayer>http://youtu.be/4a3mXelw7H4</mediaplayer>
For next week
- Get information on our literary scenario: Game of Thrones (TV series)
- Wikipedia site: http://en.wikipedia.org/wiki/Game_of_Thrones
Site on season 1: http://en.wikipedia.org/wiki/Game_of_Thrones_%28season_1%29 - Short summary of season 1 on youtube: https://www.youtube.com/watch?v=atxp6x3YreI
- Wikipedia site: http://en.wikipedia.org/wiki/Game_of_Thrones
- Read Levine et al. (in prep.), Chapter 2, Section 1 [available at olat].
- Define a model based on the Game of Thrones-scenario that contains:
- three individuals,
- two properties,
- one binary relation (2-place relation), and
- one ternary relation (3-place relation).
- Add the corresponding name symbols and predicate symbols.
For an example see the solution to this excercise. - Provide two statements that can be evaluated with respect to your model. One of them should be true, the other false.