Transcript Philosophy and Cognitive Science

384.126
Logical Foundations of
Cognitive Science
Harold Boley
NRC-IIT Fredericton
Faculty of Computer Science
University of New Brunswick
Canada
Institute of Computer Technology, TU Vienna
Winter Semester 2008/09
Adapted from a course by Kelly Inglis on Philosophy and Cognitive Science,
Philosophy Dept., University of Hong Kong, 2007-08
Optional Readings
No course textbook. Some readings are available online.
Readings for today:
1) “They’re made of meat” by Terry Bisson
home.earthlink.net/~paulrack/id82.html
2) “What’s philosophy got to do with it?” by Tim van Gelder
www.philosophy.unimelb.edu.au/tgelder/papers/WhatsPhilosophy.html
Topics for today
• What is cognitive science?
• What is the role of philosophy and logic in
cognitive science?
• The mind-body problem
What is Cognitive Science?
Cognitive science is the scientific
study of the mind.
How does the mind work?
How does the brain produce
intelligence?
Cognitive science is an on-going project
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Started in 1950s
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The term “cognitive science” was coined in
1973
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Still at early stage of development
Cognitive science is a science
• A central principle is that the mind can be
understood scientifically
• A materialist approach
Cognitive science is interdisciplinary
Draws on:
• psychology
• neuroscience
• computer science
• anthropology
• linguistics
• philosophy
• logic
The six blind men and the elephant
We are the blind men. The mind is the elephant.
Contributions of different disciplines:
• Psychology and Linguistics:
– study human behavior, how people act, how people
talk, what people say about their own mental
experiences. Learn the output of the mind.
• Anthropology:
– Learn how the brain evolved. Learn how thinking
differs in different cultures. Learn what thinking
processes remain the same in all cultures.
• Neuroscience:
– study the brain directly. See how the brain is organized, see the
brain in action (on MRI scans), experiment on animal brains,
study effects of brain damage.
• Philosophy and Logic:
– Putting it all together
– Formalizing theories about it
• Computer Science:
– Model functions of the brain in computer programs. Learn how
the brain might accomplish these functions.
– Visualize (e.g. Grailog), mechanize, and implement logics
Themes of cognitive science
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What are mental states? How do they correspond to
brain states?
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How do mental representations acquire meaning?
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Are many of our concepts and mental abilities innate,
or are they all acquired through experience?
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Is human thought conducted through a language-like
code (possibly innate) such as can be modeled in a
traditional computer program, or is thinking conducted
through a connectionist neural-network architecture?
Themes of cognitive science (cont.)
• Is “folk psychology” an accurate reflection of what is
going on in our heads? Or is it a highly-distorted
simplification?
• What is consciousness? What is the function of
consciousness?
• What is the relation between unconscious brain activities
and conscious mental functions?
• Do we have free will? Or are all our actions merely
results of the mechanical operation of physical laws?
The Role of Philosophy and Logic
in Cognitive Science
Philosophy and Logic are sometimes dismissed as obscure,
meaningless and trivial. How can such abstract unworldly disciplines
contribute to a serious scientific quest to understand the mind?
What we will do?
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Analysis
Conceptual clarification
Asking questions
Model
(and criticize and improve)
our theories
What do philosophers and logicians do for
cognitive science?
• Analyze and evaluate the arguments of others, often
showing up flaws in another cognitive scientist’s
reasoning
• Clear up conceptual confusions, often showing that
different researchers have different meanings in mind
when using the same word (e.g. consciousness).
• Ask questions, often pointing researchers towards new
directions
• Propose theories that are not (yet) empirically sound,
often spurring researchers to do the empirical studies
that can prove them right or wrong.
In “What’s philosophy got to do with it?”, Tim van Gelder
lists several roles a philosopher can play in regards to
cognitive science:
1)
The Pioneer
Historically:
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Science started as philosophy
Materialism, the basis for cognitive science
Philosophy of mind, the original cognitive science
Many specific cognitive science theories invented
first by philosophers:
– thought is a form of symbolic computation
– there is a language of thought
– the mind is modular
1)
The Pioneer (cont.)
Currently:
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The nature of consciousness
How the brain creates meaning
Do we have free will?
2) The Building Inspector
Questioning the foundations of scientific enquiry. Are
the assumptions well-grounded? Are there other, asyet-unimagined ways for things to be?
E.g. theory of relativity
3) The Zen Monk
Provides society with the assurance that someone is
thinking about deep, important problems (such as the
meaning of life), even though the results of this deep
thought may have no practical benefits to anyone.
4) The Cartographer
The philosopher is able to peruse data and theories
from the various interconnected disciplines of cognitive
science and help put it all together, drawing up a map
of what we understand of the mind and how it relates
together, and also placing the current state of
knowledge in a historical context.
5) The Dilettante
Knowing something, but necessarily not everything,
from all of the different disciplines and perspectives
available.
6) The Archivist
Following the progress of different disciplines from a
broad historical perspective.
The Cheerleader
Seeking out significant theories and lines of research and
bestowing official philosophical approval on them, thus
bolstering certain fledging new approaches to modeling
or understand the mind.
The Gadfly
Promoting startling new theories or attacking established
ideas in order to stir up debate and spur cognitive
scientists on to either defend their own theories or
consider new possibilities.
The Mind-Body Problem
How can the brain think?
Two possibilities:
1) Dualism
2) Materialism
Dualism
Two types of stuff or properties of
stuff: physical and mental
Kinds of dualism:
1) Substance dualism
• Descartes: “I am a thinking thing”
• 2 kinds of stuff: physical stuff and mind/soul stuff
• Mind stuff: immaterial, no physical properties, not
detectable by physical means
Kinds of dualism (cont.)
2) Property dualism
• There is one kind of stuff, but some stuff has two
kinds of properties: mental properties and
physical properties.
• Mental properties are undetectable by science
and do not follow physical laws
Problems with dualism
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What is non-physical stuff?
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How does mind stuff interact with physical
stuff?
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The physical affects the mental; does the
mental affect the physical?
Problems with dualism (cont.)
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The physical world is causally closed
(conservation of energy)
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The problem of epiphenomenalism
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Ockham’s razor. Why posit mind stuff?
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“Mind stuff” adds nothing to an explanation of
the mind
Materialism
Everything is physical. The mind is composed of
atoms, particles and forces. We are composed
of stardust.
The only difference is organization.
Kinds of materialism
1) Identity theory: every mental state is identical to
a particular physical state
A problem with identity theory: alien minds
2) Supervenience: The mental depends on the
physical but it is not identical.
If two people are identical in their physical
properties, they must also be identical in their
mental properties. But not vice versa.
Kinds of materialism (cont.)
3) Functionalism
Mental states are defined by their functional roles
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Functional roles relating to behavior and
relating to other mental states
Multiple realizability
Example: a chair, addition, pain
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Problems with functionalism:
Qualia
Liberalism
The “Mind-Mind” Problem
What is the relationship between the
computational mind and the phenomenal
mind?
Computational mind: intelligence
Phenomenal mind: experience
Grailog: Graph inscribed logic
Course employs Grailog for providing graph
visualizations of cognitive and metacognitive
content in logic
Examples will introduce Grailog as we go
One class will be devoted specifically to Grailog:
http://www.ict.tuwien.ac.at/lva/Boley_LFCS/LFCS-grailog.pdf
Optional Readings for next week
Focus:
Searle, John. R. (1980). Minds, brains, and programs. In Behavioral and
Brain Sciences 3 (3), 417-457, available at:
www.bbsonline.org/documents/a/00/00/04/84/bbs0000048400/bbs.searle2.html
Hofstadter, Douglas (1981), “Reflections” (on “Minds, Brains and
Programs”, in Hofstadter & Dennett, The Mind’s I (1981), 373-382
Extra:
Sober, Elliott, “Putting the Function Back into Functionalism”, in Mind and
Cognition, pgs. 63-70
Block, Ned, “Troubles with Functionalism” (excerpt), in Mind and
Cognition, pgs. 435-440