indirect realism Flashcards
what is indirect realism?
- we perceive physical objects which are mind independent
- but we do so via perceiving mind dependent sense data
- sense data are caused by and represent physical objects
- therefore, we perceive sense data immediately and physical objects indirectly
what is sense data
the content of my sensation, appearances
- the colour and shape of the desk
they are mental things which are the way we perceive them to be
- the phsyical objects can appear differently from how they really are
what arguments support indirect realism?
- argument from perceptual variation
- argument from illusio
what is the argument from perceptual variation?
p1) there are variations in perception
p2) our perception varies without corresponding changes in the physical objects we are perceiving
c1) therefore, the properties physical objects have and the properties they appear to have are not identical
c2) therefore, what we are immediately aware of in perception is not exactly the same as what exists
c3) therefore, we do not perceive physical objects directly
what is the argument from illusion?
p1) we perceive something having some property F
p2) when we perceive something having some property F, then there is something that has this property
p3) in an illusion, the physical objects does not have the property F
c) therefore, what has the property F is something mental, a sense datum
c2) therefore, in illusions, we see sense data not physical objects directly
p4) illusions can be subjectively indistinguishable from veridical perception
c3) therefore, we see the same thing namely sense data
c4) therefore, in all cases we see sense data and not physical objects
c) therefore, direct realism is false
what is scepticism about the existence of mind independent objects?
to know that physical objects cause sense-data, we first have to know that physical objects exist
- how can we know this, when the only access we have to physical objects is through our sense data?
what is the external world is the best hypothesis?
either physical objects exist and cause my sense data or physical objects do not exist nor cause my sense data
- i cannot prove either so i have to have them as hypothesis - the physical objects exist and cause my sense data is better hypothesis
the existence of physical objects provides a better explanation of my experience
- i can control imaginary experiences but not perceptual ones
different senses confirm the same information
what is the objection to the external world being the best hypothesis?
indirect realism means we still have to infer the existence of physical objects
- perception doesn’t put us in direct touch with them and scepticism still threatens
what is the response to this objection:
we do perceive physical objects - sense data don’t come between us or physical objects, they are HOW we perceive them
what are primary qualities?
a quality is a power - a physical object has to produce an idea in our mind
- a snowball produces the idea of cold and white
primary qualities are utterly inseperable from the object
- it has them whatever changes it goes through even if it is divided into smaller pieces and the object has these properties in and of itself
- e.g. size, shape, motion, etc…
what are secondary qualities?
qualities that are nothing but powers to produce various sensations to us
- colours, sounds, tastes
it is a quality that an object can have only in relation to being seen by someone
what are locke’s opinion on resemblance?
physical objects resemble our sense-data in respect of primary qualities but not secondary qualities
- the primary qualities are qualities physical objects have themselves and secondary qualities are properties of sense data alone
what is berkley’s objection to qualities?
primary qualities vary in perception just as much as secondary qualities
- our sense data are perpetually fleeting and variable so how can they resemble a physical object that is fixed and constant
- how can something we don’t experience resemble something we experience
what is the response to berkeley’s response?
indirect realists have responded by saying that sense data represent physical objects, rather than resemble them
- if two objects have the same property under the same viewing conditions, then we may infer that there is something that the two physical objects have in common
- changes in physical objects are mapped by changes in sense data
but perhaps we can’t know what it is about the physical object in itself that secures all these relations of similarity and difference
