Principles of Cognitive Science Notes - Principles of...

Principles of Cognitive Science
January 18, 2012
You are totally FABULOUS!
You are absolutely WONDERFUL!
You are a GENUIS!
Lets ROCK!
Gotta party, gotta party!
Required book: Symmetry, Causality, Mind by Michael Leyton (MIT Press).
Exam: Only one exam: Final
- 50 multiple choice questions
- Both lecture notes and book readings
IMPORTANT: Never use RateMyProfessors for this class. It damages the marking
algorithm, and lowers the grades.
Cognitive Science= the study of the knowledge functions of the mind
What is knowledge?
- Allen Newell’s answer:
o Newels definitions of knowledge: if you look at a creature, and it is
behaving with sufficient flexibility, complezity, and adaptivity. Then you
will want to say that it possess knowledge
o So he defines knowledge in terms of what it allows creatures to do.
- However, this does not actually say what knowledge is
- It is an indirect definition.
January 23, 2012
Awaken the giant within
Leyton’s theory
- Leyton gives the following direct definition of knowledge
Furthermore:
Furthermore:
- Causal explanation and memory are essentially equivalent
This class will present Leyton’s theory as opposed to Newells’s
Introduction (p1 book)

How is memory related to causal explanation?
- Imagine entering a New york subway station. You see a dented garbage can.
- Yet the present shape tells you that there was an event in the past where
something smashed into the can
- So you extracted information about the past from the object
-
But: memory = information about the past
Therefore, since the garbage can has information about the past , it has memory (for you).
How is this related to causal explanation ?
- Answer: you derive the information about the past (memory) by causally
explaining how the garbage can gets to its present state.
That is:
- One converts an object into memory by causally explaining it
- Leyton claims: All memory works in this way
Therefore:
We will say that the observer converts the object into memory
The object might be in the external environment of the observer (e.g., a dented garbage
can)
January 25, 1012
Why do we need memory?
Leyton argues: this single constraint determines the existence and the structure of mind.
1.2 The Process- Recovery Problem
- The mind is always faced with only the present. From the present, the mind must
recover the past
- The mind must carry out the following task
Also call this the process-recovery problem.
Because X is contained totally within the present, X has no duration.
i.e., it is atemporal . (a=no, temporal = time)
How can one recover the past from the present?

The past can no longer be observed.
i.e., it is inaccessible .
Therefore any arbitrary past can be conjectured.
One needs a unique past.
1.3 Process Directionality (pg 5)
- Unique recoverability forces the following fundamental constraint.
- To understand why, consider the definition of twisting
- Standard definition of twisting in computer graphics says: twisting is “hold one
end of the object, and turn the other”
- Figure 1.2 pg 5 of book
You obtain figure B from figure A by turning the end of figure A, as shown.