Consciousness

Psy315h - Class 27

(This page last updated 25 November, 2005.)
  

Up to now, we have considered cognition using the Information Processing Approach. Underlying this approach is a mechanistic assumption about the mind.

• Operates according to specific rules or laws.
• Can be measured and studied scientifically.
• Connected to the physical world.
  • Governed by laws of physics, chemistry, etc.

Can consciousness be explained mechanistically?

The word "consciousness" is used to refer to a number of different things.

•   Awareness
  • We are aware of some mental events, but not others.
  • How can we tell what is in awareness and what is not?
    • verbal report
  • Types of mental events that are generally within awareness
    • Perceptions
    • Drives
    • Emotional responses
    • Plans
    • Inner speech
    • etc.
  • Types of mental events that are generally outside of awareness
    • Early perceptual processing
    • Late motor control
    • Many aspects of language
    • Repressed memories (if they exist...)
    • Some motivations
    • etc.
• Thinking, or Higher-Level Cognition
  • Solving problems
  • Making decisions
  • Planning
  • And other things you usually can't do without being aware of it…
  • Is consciousness required for all thinking and higher-level cognition?
• Self Consciousness
  • Introspection
  • Mental representation of self
  • Is knowledge of self required for consciousness?
• Experience
  • What is it like to be conscious?
  • Qualia
  • Could your conscious experience be produced by the activity in your brain

   

Possible Solutions to the Mind-Body Problem

• Dualism
  • The brain is made of physical substance.
  • The mind is nonphysical.
• Materialism
  • Everything can be explained with one kind of substance and one type of properties.
  • No fundamental distinction between physical and mental, or between brain and mind.
  • The mind is nothing more than the physical activity in the brain.

     

Two Types of Dualism

• Substance Dualism
  • There are two types of substance.
  • Physical objects are made of physical substance.
    • Governed by the laws of Physics and Chemistry.
  • Minds are made of mental substance.
    • The mind can continue to exist after the physical body has decayed.
  • Advantages
    • Consistent with introspective impression that consciousness is nonphysical.
    • Reassuring because it allows belief in life after death.
      • NOTE: In evaluating scientific theories, reassurance does not count.
  • Disadvantages
    • Difficult to explain how the nonphysical affects the physical.
    • Difficult to explain how physical status of brain has such profound effects on consciousness.
      • brain injury
      • drugs
      • brain activity as seen in neural imaging
• Property Dualism
  • There is only one kind of substance: physical substance.
  • When physical substances are organized in certain ways (such as the neurons that form a brain), consciousness emerges.
  • Consciousness is a nonphysical emergent property of a physical brain.
  • Note: Under property dualism, you cannot have consciousness by itself. There must be a physical brain from which it emerges.
  • Two Subtypes of Property Dualism
    • Interactive Property Dualism
      • Physical activity in brain produces emergent mental properties.
      • Once the emergent properties are produced, they can affect the physical activity in the brain.
      • Helps to explain close links between physical brain and consciousness.
      • Still hard to explain how the mental interacts with the physical.
    • Epiphenomenalism
      • Physical activity in brain produces emergent mental properties.
      • The emergent consciousness has no effect on the physical brain.
      • Under epiphenomenalism, consciousness does not really control behavior.
        • If you feel that you are making conscious decisions about your behavior, it is an illusion.
        • You become conscious of the decisions after they are made by your brain.
      • Advantages
        • Helps to explain close links between physical brain and consciousness.
        • No troublesome mental effects on the physical to explain. Science can continue as it has, ignoring the mental.
      • Disadvantages
        • Troubling to think that conscious free will is an illusion.
          • Again, not a valid criterion for evaluating scientific theories.
        • If epiphenomenalism is true, why do we talk about our consciousness?

         

Pros and Cons of Dualsim

• Advantages
  • Religion
    • Although in science, we go wherever the data take us.
  • Introspection
    • Mental states seem to be different from physical states.
• Disadvantages
  • Ockham's Razor
    • Do not make theories any more complex than necessary.
    • If we can explain everything without nonphysical consciousness, why should we include it?
  • Evolutionary History
    • How could nonphysical consciousness have been produced in the course of evolution?
      •  

Two Types of Materialism

• Identity Theory
  • A mental state is nothing more than a brain state.
  • Each mental state (e.g. pain) is defined as a specific set of neurons firing.
  • Brain required to have consciousness.
    • Imagine a martian with something other than a brain supporting its cognition. Could it be conscious?
    • Could a computer be conscious?
• Functionalism
  • Each mental state defined by its function within the cognitive system.
    • Pain causes you to seek relief.
  • In other words, each mental state is defined by its causal relations.
    • Stimulus causes mental state 1.
    • Mental state 1 causes mental state 2.
    • Mental state 2 causes a specific behavior.
  • In Functionalism, each mental state is implemented in a physical system, but it does not matter how it is implemented.
  • A mental state is defined by its role in relation to other mental states.
    • According to Functionalism, a martian can have the same mental states that you do, even if it is made of green cheese.
    • Functionalism also implies that machines can have the same mental states that we do, if our functional architecture can be duplicated in a computer program.

Problems Explaining Qualia under Materialism

• Frank Jackson described the situation of "Mary the Color Scientist"
  • Mary lives in a time when every last question about the visual system has been answered.
  • Her entire visual experience is black, white, and shades of gray.
  • She has never experienced any other color.
  • What happens if Mary is shown a red rose?
    • Will she learn something about color experience that she did not already know?
    • If she really knew everything there is to know from scientific studies of color vision, what else is there for her to learn?

  
Psych 315H: Cognitive Psychology Kyle Cave Psychology Dept. U. Mass.