October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 1 Philosophical Questions Philosophy, the “love of wisdom,” is an essential component of cognitive science. Today we are going to discuss four major philosophical problems that relate to cognitive science: The mind-body problem The mind-body problem Free will versus determinism Free will versus determinism The nature/nurture debate The nature/nurture debate What is consciousness? What is consciousness?

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 2 The Mind-Body Problem Questions: How are mental properties related to physical properties?How are mental properties related to physical properties? Are there separate physical and mental universes?Are there separate physical and mental universes? If so, does the mind control the body, or vice versa?If so, does the mind control the body, or vice versa? Monism: There is only one kind of substance.Monism: There is only one kind of substance. Dualism: Both mental and physical substances exist.Dualism: Both mental and physical substances exist. Functionalism: Mental states are not just physical states, but also the functioning of those states.Functionalism: Mental states are not just physical states, but also the functioning of those states.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 3Monism Idealism: There is only the mental universe.Idealism: There is only the mental universe. e.g., George Berkeley (1685 – 1783).e.g., George Berkeley (1685 – 1783). Everything exists only in God’s mind.Everything exists only in God’s mind. Religious, mystical form of explanation.Religious, mystical form of explanation. Problem: This view is not scientific, because it cannot be tested.Problem: This view is not scientific, because it cannot be tested. Solipsism: Also assumes a mental realm only.Solipsism: Also assumes a mental realm only. The universe only exists in one’s mind.The universe only exists in one’s mind. Problem: One separate universe per mind; this subjective view cannot be experimentally tested.Problem: One separate universe per mind; this subjective view cannot be experimentally tested.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 4Monism Physicalism (materialism): Everything is physical.Physicalism (materialism): Everything is physical. e.g., Aristotle (384 – 322 B.C.), Democritus (460 – 370 B.C.), concept of atomse.g., Aristotle (384 – 322 B.C.), Democritus (460 – 370 B.C.), concept of atoms Attributes and interaction of atoms explain differences between things.Attributes and interaction of atoms explain differences between things. Similarly, they explain differences between mind and body.Similarly, they explain differences between mind and body. The operations of the mind are the operations of the brain.The operations of the mind are the operations of the brain.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 5Monism Reductive Physicalism: Neuroscience will eventually be able to account for and describe all mental phenomena.Reductive Physicalism: Neuroscience will eventually be able to account for and describe all mental phenomena. For example, one day the concept “fear” may one day be described by neurotransmitter changes in certain brain structures such as the amygdala.For example, one day the concept “fear” may one day be described by neurotransmitter changes in certain brain structures such as the amygdala. Nonreductive Physicalism: Mental phenomena are caused by physical processes, but have emergent, irreducible properties.Nonreductive Physicalism: Mental phenomena are caused by physical processes, but have emergent, irreducible properties. Mentalistic descriptions are thus still necessary.Mentalistic descriptions are thus still necessary.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 6Dualism Classical Dualism: The mind controls the body.Classical Dualism: The mind controls the body. e.g., Rene Descartes (1596 – 1650)e.g., Rene Descartes (1596 – 1650) Mind exerts control through pineal gland in the brain.Mind exerts control through pineal gland in the brain. Conforms to common sense: Feeling of hunger causes action of eating.Conforms to common sense: Feeling of hunger causes action of eating. Parallelism: Mind and body are isolated from each other.Parallelism: Mind and body are isolated from each other. Synchronization by God or through some unknown force.Synchronization by God or through some unknown force. Problem: Mystical, untestable theory.Problem: Mystical, untestable theory.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 7Dualism Epiphenomenalism: The body controls the mind.Epiphenomenalism: The body controls the mind. The mind is a side effect of the brain’s operations.The mind is a side effect of the brain’s operations. Contradicts common sense: Thoughts seem to come before actions.Contradicts common sense: Thoughts seem to come before actions. Interactionism: Mind and body affect each other.Interactionism: Mind and body affect each other. Thoughts can produce actions, and brain activity can produce thoughts.Thoughts can produce actions, and brain activity can produce thoughts. Problem: It is unclear how this influence takes place, in particular, immaterial causation.Problem: It is unclear how this influence takes place, in particular, immaterial causation.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 8Dualism Problems with Dualism: It does not explain what the mind is, only what it isn’t.It does not explain what the mind is, only what it isn’t. Postulating two separate worlds seems inelegant.Postulating two separate worlds seems inelegant. The mental universe is clearly dependent on the physical, e.g., brain damage, drug use.The mental universe is clearly dependent on the physical, e.g., brain damage, drug use. Across species, brain size is linked with cognitive ability.Across species, brain size is linked with cognitive ability.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 9Functionalism Currently most influential theory of mind.Currently most influential theory of mind. Two ways of classifying things: physical kinds and functional kinds.Two ways of classifying things: physical kinds and functional kinds. Physical kinds depend on material composition only.Physical kinds depend on material composition only. Functional kinds are identified by their actions or tendencies (e.g., all cars are of the same kind).Functional kinds are identified by their actions or tendencies (e.g., all cars are of the same kind). In terms of physical kinds, minds are identical to brains.In terms of physical kinds, minds are identical to brains. In terms of functional kinds, minds have a certain functionality that could possibly be built into any artificial or natural system.In terms of functional kinds, minds have a certain functionality that could possibly be built into any artificial or natural system.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 10Functionalism Implications of functionalism: The same mental state can be realized in different ways in two separate systems.The same mental state can be realized in different ways in two separate systems. For example, a PC and a pocket calculator can compute the same result in quite different ways.For example, a PC and a pocket calculator can compute the same result in quite different ways. Similarly, two people thinking the same thought may have different brain processes operating.Similarly, two people thinking the same thought may have different brain processes operating. Consequently, mental states cannot be reduced to any particular physical state.Consequently, mental states cannot be reduced to any particular physical state.

October 13, 2009Introduction to Cognitive Science Lecture 11: Philosophical Questions 11Functionalism Problems with Functionalism: There is currently no evidence that minds can exist apart from biological brains.There is currently no evidence that minds can exist apart from biological brains. It cannot account for qualia, i.e., what it is like to feel hungry or see the color red.It cannot account for qualia, i.e., what it is like to feel hungry or see the color red.