The knowledge argument Michael Lacewing

Substance and properties A substance is an entity, a thing, that does not depend on another entity for its continued existence. –It has ‘ontological independence’. Substances are what possess properties. Properties can’t exist without substances –They depend on substances to exist. Substances persist through changes in properties.

Substance and property dualism Substance dualism: there are two sorts of substance, mind (or soul) and matter –Minds can exist independent of bodies –Mental properties are properties of a mental substance Property dualism: there is just one sort of substance, physical substance –Mental properties are properties of a material substance, but they are fundamentally distinct from physical properties

Property dualism Physical properties don’t form the complete fundamental nature of the universe Chalmers on consciousness –‘Easy’ problem: explaining functions of consciousness in physical/functional terms –‘Hard’ problem: explaining the phenomenal properties of consciousness –These may not be analyzable in terms of function or physical structure

Jackson’s knowledge argument The set-up: a neuroscientist, Mary, who has never seen any colour, only black and white, knows every physical fact there is to know about colour vision; she is allowed to see red for the first time The claim: Mary learns something new about colour vision when she first sees red The argument: Therefore, not all facts are physical facts, and so physicalism is false. –What it is like for us to see red is not a neurophysiological or functional fact about the brain

Clarification ‘All the physical facts’: Mary knows all the facts that a completed physics and neuroscience would discover –And she knows all the facts about how things function that are entailed by those facts –If the fundamental nature of the world is entirely physical, then complete physical knowledge would be complete knowledge So Mary knows everything physical about colour vision, but she learns something new upon seeing red for the first time.

Mary gains ability knowledge Obj: Mary doesn’t learn knowledge of some new fact (knowledge that), but she gains a new ability (know how), e.g. to imagine or recognize red Reply: this is not all she learns. –You can know what it is like to see red without being able to imagine red –You can be able to imagine red, but don’t know what it is like to see red if you don’t imagine red –So new skills are neither necessary nor sufficient for the knowledge Mary gains

Mary gains acquaintance knowledge Obj: Mary doesn’t learn about a new fact, but becomes directly aware of red (acquaintance knowledge) –Suppose what it is like to see red is some property of the brain. Mary knows about this property, but her brain has never had this property, so she isn’t acquainted with it Reply: acquaintance knowledge includes knowing a new fact – what it is like to see red –Jackson: Mary learns something new about other people’s colour experience

There is more than one way of knowing the same fact The concept of water is a different concept from that of H 2 O, but they are the same property. –Two ways of thinking about the same ‘stuff’ To know that there is water in the glass is not to know that there is H 2 O –These are different facts, counting by concepts (how we think about the world) –These are the same fact, counting by properties (how the world is)

There is more than one way of knowing the same fact Mary has a theoretical concept of red –Wavelengths of light, neurons firing, etc. On seeing red, Mary gains a new, phenomenal concept of red –A concept based on experiencing something Mary can think about seeing red in a new way, but she is thinking about the same physical property in the world

There is more than one way of knowing the same fact Physicalism is about what exists (properties), not about how we think about what exists (concepts) So even if Mary learns something new, this doesn’t show that physicalism is false

Does Mary learn anything new? If Mary really did know everything physical about seeing red, she would not learn anything when she sees red –The experience of seeing red is nothing more than highly detailed knowledge of what it is to see red, and Mary has this Counterintuitive: you can’t work out what it is like to experience a colour if you have never seen one Reply: but what is the argument for this? The intuition that Mary will be surprised is not enough