Epiphenomenalist Dualism

• Epiphenomenon 


  Secondary effect or by-product
• Epiphenomenalism

  • Mental states are a by-product of the brains function
  • mental states are causally inert - they themselves cause nothing
  • The brain causes us to act
  • mental states are still immaterial (dualism) even though they are brought about by physical brain states
• The physical world can cause mental states but mental states cannot cause changes in the real world

  • causal interaction goes one way
• TH Huxley - Darwins Bulldog

  • Supports mechanistic account of bodily action
  • bodily processes determined by physical states (not mental ones)
  • true not only of animals but humans also
• Descartes and Animals

  • Huxley was inspired by mechanistic theories from Descartes
  • Descartes argued that animals were pure automatons (biological robots)
  • purely mechanistic with no consciousness
  • led him to conduct vivisections on animals
• Conscious Automaton

  • Huxley though Descartes was wrong to deny animals consciousness
  • huxley thought humans and animals were conscious but that it played no causal role in our behaviour
  • makes us 'passengers' in our own bodies
  • unconscious mechanistic processes in the driving seat
• Strengths of Epiphenomenalism

  1. Solves cartesian interaction problem
  2. experimental evidence supports it
  3. fits with evolution and scientific understanding of human behaviour
  4. explains how mental states change according to brain states
• Solves cartesian interaction problem - strength

  • Problem - how can an immaterial substance (mind) interact/cause a physical substance (body)
  • avoids the problem -> in epiphenomenalism, its all physical to physical causation
• Experimental evidence - Benjamin Libet experiment - strength

  • neuroscientist who assessed how humans react to certain stimuli
  • brain seemingly sends a signal to move the body before you are aware to move it
  • suggests body is moving of its own free will
• Fits with evolution - strength

  • white bones are a by-product of calcium
  • back pain is a by-product of evolving to walk up right
  • sometimes things evolve with no specific purpose
• Explains why mental states change alongside physical states - strength

  • if mental-states are a by-product of brain states then this would explain why changes to the body bring about changes in the mind (Phineas Gauge)
  • more precise than substance dualism
• Objections to epiphenomenalism

  1. introspection
  2. mental states do have causal powers
  3. free-will
  4. evolutionary disultility
  5. own interactionist problem
• Experimental evidence - TH Huxley example

  • A soldier with severe PTSD may perform complex actions without being aware of it - reloading a rifle motion or singing
  • Appears to be acting on ‘autopilot’
  • Complex behaviours don’t require conscious experiences as their cause
• Objections to Epiphenomenalism

  1. Introspection
  2. mental states DO have causal powers
  3. Free-will
  4. Evolutionary Disutility
  5. Has its own interactionist problem
• Issues: Introspection


  Introspection is the process of looking into ones own mind to examine it

  • Mental states do cause bodily behaviour
  • If mental states have no causal powers then knowledge of mental states is impossible
  • seems counter-intuitive to believe
• Possible response to introspection - TH Huxley

  • we think we have conscious control over our actions but there is nothing in experience that can establish that we do
  • all experience reveals is that certain volitions are correlated
  • consistent with them being both a cause and a side effect
• Issues: Introspection (2)

  • mental states can cause other mental states
  • if someone is in constant chronic pain it may make them feel sad
  • being in pain -> causes -> being sad
• Issues: Free-will

  • If mental states have no causal powers then there is no free-will which is counter-intuitive
  • The denial that our decisions are free costs us our moral responsibility
• Perspectives on free-will - Libertarianism


  Yes we have free will. Free will means ‘I was able to do other than what I did’, not all actions are determined
• Perspectives on free will - compatibilism 


  Yes we have free will - ‘I did what I wanted to’ , all actions are determined but so long as you follow your desires your actions are free
• Prespectives on Free-will - Incompatibilism


  No we don’t have free will, free will means ‘I am able to do other than what I did’, all actions are determined
• Response to free-will issue

  • Epiphenomenalists may argue that they are compatibilists- one is free so long as they are acting consistent with their desires
  • Huxley argues that his desires may not cause his actions but as long as he performs actions that fulfill his desires he is free
• Issue - Its own interactionist problem

  • interactionist problem (Elizabeth b) held that the physical and mental surfaces could not touch
  • supposedly epiphenomenalism avoids this as all causal interaction is physical-physical
  • BUT mental states do cause other mental state and brain states can also cause mental states
• Issue - Evolutionary Disutility

  • consciousness is a big thing to be an accidental evolutionary by-product like epiphenomenalism suggests
  • if mental states have no causal powers then why would evolution select for them if they don’t aid survival
• Frank Johnson response to evolutionary disutility

  • rejects evolutionary disutility
  • there are things that are a by-product of evolution but the advantages outweigh the disadvantages
  • polar bears adapted a thick coat to stay warm in cold climates
  • a by-product of their warm coat is that they are heavy
  • mental states are by-products of brain states in the same way
  • the complex processes of the brain allow for mental states to occur
  • still believes they have no causal role in behaviour