Multilevel Mechanistic Models and Explanation of Consciousness by student19

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									Multilevel Mechanistic Models
                      and

Explanation of Consciousness
              Antti Revonsuo
   Academy of Finland and University of Turku
      “The Search for a Unified Theory”



* what is required for theoretical unification?
>> A Unified Research Program
       Unified Research Program

> defines a set of fundamental background
  assumptions
       Unified Research Program

> defines a set of fundamental background
  assumptions

  >>shared by the community of researchers in
  the field
       Unified Research Program

> defines a set of fundamental background
  assumptions

  >>shared by the community of researchers in
  the field

  >> guide further theoretical and empirical
  research in the field
Delivers a coherent overall story:



  The “Big Picture”
The Unified Theory of Consciousness


> shared background assumptions about the
 nature of consciousness
The Unified Theory of Consciousness


> shared background assumptions about the
 nature of consciousness

>> that guide empirical and theoretical
 research to fruitful directions
The Unified Theory of Consciousness


> shared background assumptions about the
 nature of consciousness

>> that guide empirical and theoretical
 research to fruitful directions

>> the “Big Picture” about the explanation of
 consciousness
     Current situation:
No shared core assumptions
             Current situation:
        No shared core assumptions


> only a wide variety of different philosophical
  views:
      * functionalism, panpsychism, eliminativism,…
             Current situation:
        No shared core assumptions


> only a wide variety of different philosophical
  views:
      * functionalism, panpsychism, eliminativism,…


>> what is the proper empirical context for a
 unified scientific research program on
 consciousness?
* The only existing cases of phenomenal
  consciousness (creatures housing subjective
  experience) we can be relatively sure about
  are biological organisms with complex nervous
  systems
* The only existing cases of phenomenal
  consciousness (creatures housing subjective
  experience) we can be relatively sure about
  are biological organisms with complex nervous
  systems

* Consciousness has become a central topic of
  research in the biological sciences, especially
  neuroscience

      >> a biological research program on
      consciousness?
A Biological Research Program on Consciousness?
A Biological Research Program on Consciousness?


> If we search for a unified theory of consciousness in the
   context of the biological sciences, what might it look like?
A Biological Research Program on Consciousness?


> If we search for a unified theory of consciousness in the
   context of the biological sciences, what might it look like?



>> what is the nature of theoretical explanation in
 the biological sciences?
Explanation in Biological Science
     Explanation in Biological Science


* Multilevel mechanistic explanation
     Explanation in Biological Science


* Multilevel mechanistic explanation

>> different from traditional “theory reduction” or
      “Deductive-Nomological” -explanation
BIOLOGICAL EXPLANATION
       BIOLOGICAL EXPLANATION

* multiple levels of organization, forming a
hierarchical, causal-mechanical network
       BIOLOGICAL EXPLANATION

* multiple levels of organization, forming a
hierarchical, causal-mechanical network

* not describable in terms of laws or linguistic
representations but by complex multilevel models
      > visualizations, graphical maps, computer
      simulations
       BIOLOGICAL EXPLANATION

* multiple levels of organization, forming a
hierarchical, causal-mechanical network

* not describable in terms of laws or linguistic
representations but by complex multilevel models
      > visualizations, graphical maps, computer
      simulations


* adequate research instruments decisive also for
theoretical progress
          Explanation in Biological Science


NATURE:              A hierarchy of Levels of Organization



SCIENCE:             The corresponding Levels of
                     Description

                     Placing a phenomenon in this
EXPLANATION:
                     hierarchical network
          Explanation in Biological Science


NATURE:              A hierarchy of Levels of Organization



SCIENCE:             The corresponding Levels of
                     Description

                     Placing a phenomenon in this
EXPLANATION:
                     hierarchical network
          Explanation in Biological Science


NATURE:              A hierarchy of Levels of Organization



SCIENCE:             The corresponding Levels of
                     Description

                     Placing a phenomenon in this
EXPLANATION:
                     hierarchical network
Craver & Darden 2001
How to place consciousness in this framework?

>>A Reconceptualization of Consciousness:
  CONSCIOUSNESS =
The Phenomenal Level of
Organization in the Brain
Explanation of Consciousness




 INPUT-                OUTPUT - description
            Explanation of Consciousness


1. The Phenomenal-Level Description
1. The Phenomenal-Level Description
1. The Phenomenal-Level Description


* a systematic description of phenomenal experience on its
   own terms
1. The Phenomenal-Level Description


* a systematic description of phenomenal experience on its
   own terms

* the structure, organization, unity, and temporal
   dynamics of consciousness..
1. The Phenomenal-Level Description


* a systematic description of phenomenal experience on its
   own terms

* the structure, organization, unity, and temporal
   dynamics of consciousness..

>>… as revealed by empirical methods in psychophysics,
  experimental psychology, neuropsychology, dream
  research etc.
1. The Phenomenal-Level Description


* a systematic description of phenomenal experience on its
   own terms

* the structure, organization, unity, and temporal
   dynamics of consciousness..

>>… as revealed by empirical methods in psychophysics,
  experimental psychology, neuropsychology, dream
  research etc.

* provides top-down constraints on what could serve as
   the lower-level constitutive mechanisms of
   consciousness
             Explanation of Consciousness


1. The Phenomenal-Level Description
2. The Constitutive Explanation (downward-looking)
2. The Constitutive Explanation (downward-looking)

* moves from the phenomenal level to the underlying
  levels of organization (level -1)
2. The Constitutive Explanation (downward-looking)

* moves from the phenomenal level to the underlying
  levels of organization (level -1)

* integrates top-down and bottom-up constraints into one
   coherent cross-level model
2. The Constitutive Explanation (downward-looking)

* moves from the phenomenal level to the underlying
  levels of organization (level -1)

* integrates top-down and bottom-up constraints into one
   coherent cross-level model

* seeks explanatory relationships between features of the
   phenomenal level and features of the lower-level
The Neural Correlates of Consciousness (NCC):
   The Neural Correlates of Consciousness (NCC):



* correlation is a non-explanatory relationship!

> a true explanation MUST go beyond mere correlations
   The Neural Correlates of Consciousness (NCC):



* correlation is a non-explanatory relationship!

> a true explanation MUST go beyond mere correlations



*A cross-level model is required, relating phenomenal
features to their constitutive micro-level mechanisms
             Explanation of Consciousness


1. The Phenomenal-Level Description
2. The Constitutive Explanation (downward-looking)
3. The Etiological Explanation
   (backward-looking)
3. The Etiological Explanation
   (backward-looking)

* tracks the causal history of the phenomenon in the
   temporal dimension
3. The Etiological Explanation
   (backward-looking)

* tracks the causal history of the phenomenon in the
   temporal dimension

* different temporal scales for different types of etiological
   explanation:
3. The Etiological Explanation
   (backward-looking)

* tracks the causal history of the phenomenon in the
   temporal dimension

* different temporal scales for different types of etiological
   explanation:

  > IMMEDIATE (proximate) causal history
  >> DEVELOPMENTAL history
  >>> EVOLUTIONARY (ultimate) history
             Explanation of Consciousness


1. The Phenomenal-Level Description
2. The Constitutive Explanation (downward-looking)
3. The Etiological Explanation
   (backward-looking)
4. The Contextual Explanation
   (upward-looking)
4. The Contextual Explanation
   (upward-looking)

* moves from the phenomenal level to level +1
4. The Contextual Explanation
   (upward-looking)

* moves from the phenomenal level to level +1

* describes the interaction between conscious phenomena
   and nonconscious stages of sensory and motor
   processing
SENSORY   BEHAVIORAL
INPUT     OUTPUT
4. The Contextual Explanation
   (upward-looking)

* describes the causal powers of the phenomenon at the
   higher level of organization
4. The Contextual Explanation
   (upward-looking)

* describes the causal powers of the phenomenon at the
   higher level of organization

  > the causal contribution of consciousness to organism-
  environment interaction:
4. The Contextual Explanation
   (upward-looking)

* describes the causal powers of the phenomenon at the
   higher level of organization

  > the causal contribution of consciousness to organism-
  environment interaction:

      Can epiphenomenalism be defeated?
               5. Input-Output function

* sometimes useful just to describe the operation of a
   phenomenon from start conditions to finish conditions
   without yet specifying the micro-level mechanisms
               5. Input-Output function

* sometimes useful just to describe the operation of a
   phenomenon from start conditions to finish conditions
   without yet specifying the micro-level mechanisms

* An algorithm describing a particular input-output
   function may be realized in a computer program as a
   simulation of the function
5. Input-Output function
                5. Input-Output function

* sometimes useful just to describe the operation of a
   phenomenon from start conditions to finish conditions
   without yet specifying the micro-level mechanisms

* An algorithm describing a particular input-output
   function may be realized in a computer program as a
   simulation of the function

* the algorithm is an abstract entity,
                5. Input-Output function

* sometimes useful just to describe the operation of a
   phenomenon from start conditions to finish conditions
   without yet specifying the micro-level mechanisms

* An algorithm describing a particular input-output
   function may be realized in a computer program as a
   simulation of the function

* the algorithm is an abstract entity,

  > it´s not identical to the phenomenon
  > it´s not a complete explanation of the phenomenon
  > it may help to constrain the explanation
Explanation of Consciousness




 INPUT-                OUTPUT - description
            The Big Picture

What do the different sources of evidence
     contribute to the overall story?
                The Big Picture

What do the different sources of evidence
     contribute to the overall story?

  > implicit-explicit dissociation, blindsight, neglect,
    binocular rivalry, change blindness, inattentional
   blindness, dreaming, hypnosis, perceptual binding,
  neural synchronization, functional brain imaging and
                    NCC experiments...
Explanation of Consciousness:
  Framework for the Big Picture




 INPUT-                    OUTPUT - description
                      Where to start?


1) Conceptual clarification of different forms of
   consciousness
       1.1. Primary/phenomenal consciousness
       1.2. Reflective consciousness, introspection, verbal report
       1.3. Self-awareness

2) Relation between:
       * consciousness and attention?
       * consciousness and self?
   Basic Concepts in Consciousness Research


1) Primary or Phenomenal Consciousness

2) Reflective Consciousness

3) Introspection

4) Self-awareness
            PRIMARY CONSCIOUSNESS


* core element: phenomenality or subjective experience

* the mere having or the presence of subjective
   experience for an organism, in any sensory or
   cognitive domain

* what it is like to be this subject, here and now

* the organism’s subjective psychological reality
 PRIMARY CONSCIOUSNESS


     * Antonio Damasio:
   Core Consciousness

        * Ned Block:
Phenomenal Consciousness
           REFLECTIVE CONSCIOUSNESS


* some content in primary consciousness becomes the
   object of further conscious processing in an act of
  reflection

* thinking, categorizing, evaluating, passing a judgement
   about the content of primary consciousness

* cognitive operations which take phenomenal experience
   as input


>> therefore, RC goes beyond the mere presence of subjective
  experiences (or Primary Consciousness)
                    INTROSPECTION


* reflective consciousness + (verbal) report

* communication of the content of primary
   consciousness

* Examples from empirical research:

  - verbal dream report
  - categorical keypress to a stimulus perceived consciously
                    SELF-AWARENESS


* a form of reflective consciousness

* requires an internal self-representation

* the ability to become aware of one’s own phenomenal
   experiences as one’s own experiences

        >> reflective consciousness connects the current self-
  related experience to an enduring self-representation

       >> Tulving: Autonoetic consciousness; mental time travel
       >> Damasio: Extended consciousness
                    Recent results


- primary and reflective consciousness have different
   EEG-correlates

- NCC of primary consciousness is not dependent on
   attention, but NCC of reflective consciousness is
   strongly modulated by attention

- inattentional blindness is inattentional amnesia of the
   momentary contents of primary consciousness
the
END
Explanation of Consciousness:
  A Framework for the Big Picture
1) PHENOMENAL LEVEL

2) CONSTITUTIVE MECHANISMS

3) ETIOLOGICAL EXPLANATION

4) CONTEXTUAL EXPLANATION
        * What happens to organism-environment interaction as a
  consequence of the selective (reversible) knockout of the phenomenal
  level?
A SELECTIVE KNOCKOUT
OF THE PHENOMENAL LEVEL ?
A SELECTIVE KNOCKOUT
OF THE PHENOMENAL LEVEL ?
                        >> ZOMBIES??
          The Zombies Among Us
             (Revonsuo et al. 2000)




>> automatic behaviors in
epilepsy and sleep disorders!
The Zombies Among Us
   (Revonsuo et al. 2000)
Explanation of Consciousness:
     A Framework for the Big Picture
the
END

								
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