Jackson, Epiphenomenal Qualia - · PDF fileJACKSON’S KNOWLEDGE ARGUMENT FOR DUALISM ... Fact that seeing red causes r-stimulation = Fact that seeing red is like this

EPIPHENOMENAL QUALIAFrank Jackson

MARY, VISION SCIENTISTthought experiment

JACKSON’S KNOWLEDGE ARGUMENT FOR DUALISM

➤(1) and (4) true by stipulation

➤Re (2): Mary wouldn’t know what colors look like before release ➤“blue banana trick”

➤Re (3): only way to gain new knowledge is by learning new facts

1. Mary has complete physical knowledge before her release.

2. Mary lacks phenomenal knowledge before her release.

3. If Mary has complete physical knowledge without phenomenal knowledge, then phenomenal facts are not physical facts.

4. Materialism says that phenomenal facts are physical facts.

5. Therefore, materialism is false.

REPLIES TO JACKSON

➤ Some reject “(2) Mary lacks phenomenal knowledge before her release.”

➤ Most reject “(3) If one can have complete physical knowledge without phenomenal knowledge, then phenomenal facts are not physical facts.”

➤ Objection 1: Mary gains new abilities, not new factual knowledge (“Ability Hypothesis”)

➤ Objection 2: Mary learns old facts in a new way.

Fact that water is in my glass = Fact that H2O is in my glass

Knowledge that water is in my glass ≠ knowledge that H2O is in my glass

Fact that seeing red causes r-stimulation = Fact that seeing red is like this

Knowledge that seeing red causes r-stimulation ≠ knowledge that seeing red is like this

DESCARTES’ MODAL ARGUMENT FOR DUALISM

➤Re (2): God is omnipotent, so… ➤“everything which I…

understand is capable of being created by God”

➤Re (3): Descartes says that “two things are distinct” if “they are capable of being separated.” ➤separated = one existing

without the other existing ➤Follows from “It is impossible

for a single thing to both exist and not exist.”

1. I can understand a scenario where I exist but no material objects exist.

2. Every understandable scenario is possible.

3. If it is possible for X to exist without Y existing, then X is not Y.

4. I am not a material object.

JACKSON’S MODAL ARGUMENT FOR DUALISM

➤Re (1): “No amount of physical information about another logically entails that he or she is conscious…”

➤Re (2): Consistency a common guide to possibility.

➤Re (3): A supervenes on B = (same A ⇒ same B)

1. A scenario where our physical duplicates lack consciousness is logically consistent.

2. Every logically consistent scenario is possible.

3. Materialism says that consciousness supervenes on the physical.

4. Materialism is false.

Epiphenomenalism: mental states have physical causes but no physical effects

epi (“=above / in addition to”) + phenomenon + ism

MIND-BODY INTERACTION

DIRECTLY PERCEIVED

objections to epiphenomenalism

QUALIA MUST

PROMOTE FITNESS

objections to epiphenomenalism

BEHAVIORAL EFFECTS

NEEDED FOR EVIDENCE OF

OTHER MINDSobjections to

epiphenomenalism