Surprise by lanyuehua

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									 It’s a surprise!


 Ron Chrisley
 COGS
 Department of Informatics
 University of Sussex
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                             E-Intentionality, PAICS Research Group, Department of Informatics
                                                            University of Sussex, June 1st 2006
               Surprise!
• Why is the title of this talk "It's a
  surprise!"?
• It's a surprise!

But first…
                      …some logic (groan)
  Logic: What is it good for?
• One application: To make explicit
  the logical structure of an
  inference
• Then it becomes a
  mechanical/syntactic matter to
  determine, e.g. validity
             Arguments
• Ron says: "All men are mortal.
  Socrates is a man. Therefore, Socrates
  is mortal."
• Michael says: "Every man is mortal.
  Socrates is a man. Thus, Socrates is
  mortal."
• Blay says: "All men are mortal.
  Schwarzenegger is a man. Therefore,
  Schwarzenegger is mortal."
• Different words, but same logical form…
             Logical form
Ax[M(x)->D(x)]
M(S)
-----
D(S)

• So if one of the arguments is valid, the
  others are.

• This logical form is valid.
             My claim
• Either logical form does not
  determine validity (a
  contradicition, or damn near it),
…Or…
• Standard means of translating
  arguments into their logical form
  are incorrect.
              Problem case
• Consider: "Ron has drawn 10
  conclusions today. 10 is less than 11.
  Therefore, Ron has drawn fewer than
  11 conclusions today."

C(R,t) = 10
10 < 11
-----
C(R,t) < 11


• Is this valid?
                Validity
• Perhaps for you, but not for me!
• The problem is that carrying out the
  inference interacts with the truth of the
  premises of the inference
• So either we need to say that validity
  does not supervene on logical form, or
  the foregoing is not the logical form
     Embodied logical form
• But what is the logical form, then?
• Needs to include the person who is
  carrying out the inference?
• What else? Timing? Order?
     Connection to paradoxes
• Moore’s paradox:
    – “Ron cannot know this sentence to
      be true”
•   Gödelian argument
•   Newcomb’s problem
•   Liar paradox
•   Rationality paradox/prisoner’s
    dilemma
SURPRISE!

								
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