Perception as a source of knowledge (Epistemology) Flashcards
What is Direct realism?
Direct realism is the belief that we immediately perceive mind independent physical objects, and our senses detect the properties of these objects
The objects retain these properties when unperceived
(eg. Leaving an apple in a drawer, it still retains its properties when forgotten about)
Perceptual variation (counter to direct realism)
Perceptual variation (counter to direct realism)
Argues that DR is false as the appearance of physical objects depends on the conditions under which they are perceived
Perceptual variation argument(Russells table example)
Against DR
P1) The brown table appears white when under a light, but brown otherwise
P2) The shape of the table also appears to be bigger or smaller depending on the angle at which it is perceived
P3) We need to make the distinction between the “real” table and the variations acting on the table
C1) Means direct realism is false as the table isn’t immediately known to us, and we do not perceive objects as they truly are
What is the hallucination arguement
Against DR
Hallucinations happen when humans perceive something mind-dependent (which doesn’t exist outside of their own mind)
P1 Hallucinations can be selectively indistinguishable from veridical perceptions (Truthful accurate representation)
P2 If they are subjectively indistinguishable, then they must be aware of the same thing in both cases
C1 This means that during veridical perception what we directly perceive is sense data
C2 meaning we perceive the world indirectly making direct realism false
What is the illusion argument?
Disagrees with DR as we can be subject to illusions, which distort our perception of reality, meaning immediate objects of reality can’t be material objects
P1 When under an illusion, an object can appear to have a different property (Eg a “bent” straw in water)
P2 The perceiver is directly aware of this apparent property
P3 But the object doesn’t have this property in reality
C1 So what we perceive in comparison to the actual reality is different
C2 Which makes direct realism false as we need to make the distinction between what is apparent and what is real
What is the time lag argument?
P)Light from distant objects (aka the sun) take 8 minutes to travel
C1)If the sun ceased to exist, what we see might not actually exist
C2)So what we see and the current state of an object are two different things
C3)So what we directly perceive are merely appearances and not physical objects, making direct realism false
What is indirect realism?
The belief that we perceive the world and physical objects indirectly through sense data(We are directly aware of this, these are appearances)
The external world exists independently of our minds
But we perceive this world indirectly through sense data
What are Locke’s primary and secondary quality distinctions
In support of IR
Idea: Whatsoever the mind percieves in itself, or the immediate object of perception
Quality: The power to product any idea in our mind
Primary qualities (Shape, size, motion, position) are inseparable from an object, meaning however the object is altered, it must still retain some size, or position. Without these qualities, they wouldn’t be essential at all
P1: If you continually divide an object, the parts must retain the primary qualities even when they are to small to be percieved
P2: Therefore primary qualities exist mind independently
Secondary qualities are “powers” that produce a sensation in us, and they alter and vanish. Secondary qualities are dependent on primary qualities and require a mind to appear (eg. a pounded almond visibily changes, alongside its taste and colour, and if we block our senses its becomes null)
Indirect realism leading to scepticism
According to IR, we directly perceive sense data
if we only perceive sense data how can we truly know anything about the external world, there’s no way of telling
theoretically, it would be illogical to assume that there is an external world that causes the sense data
we cannot go beyond the veil of perception ( sense data)
Hot and cold water example (defending primary qualities)
If two people put their hands in hot and cold water
and then dip their hands into lukewarm water
One hand will be warm and the other cool
The same thing cannot be hot or cold simultaneously
Hotness or coldness doesn’t exist in the water, but within us
its merely a sensation produced by secondary qualities or waters primary qualities
What is sense data?
Acts are intermedium between perciever and what is percieved
Sense data are mind-dependent representation of reality, and can only exist when being experienced
We perceive the sense-data or ideas immediately, not the physical objects
Idealism
View that there is no external world independent of our mind
we percieve ideas directly meaning the immediate objects of perception are mind dependent
Berkley’s attack on prim sec qualities
berkley agrees that sec qualities are md, he uses some aspects of PV
something that looks small to me will look large to an animal
a material object cant be small and big at the same time
the percieved shape of an object depends on the angle of observation
but it can’t have a different shape at different times
this proves primary qualities are mind dependent
Master argument
Try too imagine an object that is unpercieved by anyone
in doing so you are still percieving the tree
therefore the tree is in your mind and not independent of any mind
Problems with idealism
An immaterial world existing in our minds goes against common sense
(candle wax argument)
