Materialism
•	Definition
•	Issues
•	Early speculations
•	Metaphors
•	Localization
Materialism
•	Doctrine that thought and behavior can be reduced to physical – typically body
–	Usually that thoughts are nothing more than bodily behaviors
–	But depends heavily on metaphor
•	Body as machine
•	Always involves a reductionist program
Issues
•	Mind-body
–	Can all thought be reduced to material substance --  Descartes?
–	Implications for free will
•	Localization
•	Complexity of matter
–	Is thought related
–	How to avoid panpsychism
•	Metaphors
Early speculations
•	Little anatomical information
•	Few methods to study living organisms
•	Nerves
–	Well known from ancient times
–	But little knowledge of how they worked
–	Speculation about nerve juice, vital forces, etc.
•	Harvey and circulation of blood 
The Metaphors
•	Natural spirits
•	Motion
•	Vibrations
•	Muscle
•	Electricity
•	Magnetism
•	Computers
•	Connectionist
The Metaphor of Natural Spirits
•	Body was inert and animated by spirits
•	Greek and medieval creation
•	What gives life to living things
•	Minimal speculation about how worked
Finding the Life Force
•	Living matter is entirely different from physical
–	Principle of life must be internal to bodies
–	Living bodies were self-organizing and active
•	Also Cartesian dualism 
The Motion Metaphor 
•	Based on work of Galileo where motion is crucial
•	Bodies in physical world show motion
–	Human bodies are physical objects
–	And therefore subject to same motions
•	Then why not thoughts – prior to Descartes?

The Vibrations Metaphor
•	Based on Newton
–	Action at a distance
–	The ether
•	Advantage of linking psychology to physics
Electricity
•	Much speculation in 18th Century
•	Descartes’ ideas of reflexes
•	Galvani’s frogs
–	Organic battery
–	Volta’s suggestion that frog leg conducted electrical impulses
•	Bois-Reymond (1818-1896)
–	Life’s work on electrical nature of nerves
–	Action potential
–	Demystified nerves
•	No more vital forces
•	Now part of science
Magnetism
•	Idea that magnetism was related to mental illness
•	Mesmer (1734-1815)
–	Magnets could cure mental illness
•	Led to hypnosis
Information Processing
•	The mind is a computer or computer-like
•	Processes information sequentially
•	And in an ordered fashion
Connectionism 
•	Computer metaphor
•	Neurons form complex interrelationships
•	Can be modeled on computer
The Localization Issue
•	Idea that specific mental functions are localized in particular parts of the brain
–	Built on notion of discrete mental functions
–	Assign to different brain parts
•	Phrenology
•	Neurological models
Phrenology
•	Gall (1758-1828)
–	Localization
–	Brain grows with function
–	Can be read off via bumps on head
•	Spurzheim (1776-1832)
–	Collaborated with Gall
–	Populaizer
Neurological Models
•	Flourens – ablation method
•	Phineas Gage
•	Language
–	Broca (1824-1880)
•	Understand but not speak
•	Left frontal lobe
•	Considerable investigation
–	Wernicke (1848-1904)
•	Language comprehension deficits – left temporal lobe
•	Fluent but meaningless speech