Epistomology Flashcards
Russell’s Perceptional variation arg (counter for direct realism) + reply
Russell uses the example of a shiny brown desk - we say it’s brown but it doesn’t actually look an even colour all over: depending on how the light falls, some parts are lighter than others, and some are even white from the shininess. Does this mean that the brown colour is more real than the other colours experienced?
This example draws our attention to a distinction between appearance and reality.
This causes problems for the direct realist as they said they perceive objects ‘directly’ but through sense data
Main argument:
1) there are variations in our perception
2) our perception varies without corresponding changed in the physical object we perceive ( eg the table remains rectangular, even as the way it looks cheated at different angles)
3) therefore, the properties physical objects have and the properties they appear to have are not identical
4) therefore we do not perceive physical objects directly
Reply:
What we mean by the colour of the object is the colour that it appears to have when seen by normal observers in normal conditions.
Direct realism
The belief that physical objects we perceive exist independent of our minds
The argument from illusion (counter for direct realism) + reply
If you half submerge a straight stick in a glass of water, it looks crooked: but it isn’t. We see a crooked stick, but the stick isn’t crooked. However, just from what you experience, you can’t tell whether it’s an illusion or not. Someone who doesn’t know about the crooked stick illusion thinks they are seeing a crooked stick.
1) we perceive something having some property F
2) when we perceive something having some property F, then there is a something that has this property
3) in an illusion, the physical object does not have the property F (the stick is not bent)
4) therefore, what has the property F is something mental, a sense-datum
5) therefore, in illusions, we see sense-data, and not physical objects immediately
6) illusions can be ‘subjectively indistinguishable’ from veridical perception
7) therefore, we can see the same thing, namely sense data, in both illusions and veridical perception
8) therefore, in all cases, we see sense data and not physical objects, immediately
9) therefore, direct realism is false
Reply:
- 2 is wrong. It has the property of looking crooked
- same reply for perceptional variation
The argument for hallucination (counter for direct realism) + reply
1) in a hallucination, we perceive something having some property F
2) when we perceive something have a property F, then there is something that has this property
3) we don’t perceive a physical object at all (unlike the case of illusion)
4) therefore, what we perceive must be mental - sense data.
5) hallucinations can be experiences that are subjectively indistinguishable from veridical perception.
6) therefore, in all cases, we see sense data, and not physical objects, immediately
8) therefore, direct realism is false
Reply:
2) according to the disjunctive theory of perception, if something looks a certain way then either, i directly perceive a mind independent physical object that is f or as in the case of hallucination, it appears to me just as if there is a something that is F, but there is nothing that is F.
Russell’s The time lag argument (counter for direct realism) + reply
It takes 8 minutes for light from the sun to reach the earth. Therefore, it can be argued that we do not perceive objects directly.
Reply: direct realism can reply that this is a confusion of how we perceive and what we perceive. Direct realism can argue that except in special conditions, we don’t perceive light waves directly and physical objects indirectly. Light waves are part of the story of how we see physical objects
Common sense/intuition (supporting reason for direct realism)
Describe what you see. You would normally do this by referring to physical objects. If you perceive the world via sense data, the immediate content of what you perceive is mental. If you try to describe through sense data however, it is virtually impossible for a normal scene. What this shows is that our perceptual experience presents what we perceive as mind independent objects. That doesn’t prove that we perceive mind independent objects, but it does make such a claim highly intuitive
Indirect realism
We do not perceive physical objects directly (indirectly), only through sense data. However, they are mind independent
Sense data
Sense data are mental images or representations of what is perceived, * the content of perceptual experience *. If sense data exist, they are the immediate objects of perception and are private, mind dependent mental things
scepticism about the existence of the external world (counter for indirect realism) + reply
Russell in the problems of philosophy chapter 2 argues that if what we perceive directly are sense data, then all that we know about are sense data. We believe that behind the sense data there are real physical objects and that these cause our sense data. But how can we know this? To know that physical objects cause sense data we must first know whether they exist. But the only access we have to physical objects is through our sense data.
Although Russell doesn’t comment on this, his line of thought form a objection to indirect realism. Because we directly perceive sense data, we cannot know that a world of physical objects - a world external to and independent of our minds - exist. Scepticism is the view that we cannot know, or cannot show that we know, a particular claim, in this case the claim that physical objects exist. Indirect realism leads to scepticism about the existence of the external world.
Reply:
1) The fact that sense data are private means that no two people actually ever perceive the same thing. They have similar sense data if they are at the same place and time. The best explanation of this is that there are physical objects causing their sense data.
This arguments however is rejected by Russell as it assumes something we can’t know: that there are other people, and that they have sense data, and that their sense data are similar to mine. To assume that there are other people is to assume that there are physical objects, since people are physical objects.
2)
1. Either physical objects exist and cause my sense data or physical objects do not exist nor cause my sense data
2. I can’t prove either claim is true
3. Therefore, I have to treat them as hypothesis
4. The hypothesis that physical objects exist and cause my sense data is better
5. Therefore, physical objects exist and cause my sense data
Scepticism
The view that we can not know, or cannot show that we know, a particular claim.
Russell’s cat argument (supporting argument for indirect realism replies)
If I see a cat first in a corner of the room and then later on the sofa, then if the cat is a physical object, it travelled from the corner to the sofa when I wasn’t looking. If there is no cat apart from what I see in my sense data, then the cat does not exist when I do not see it. so the hypothesis that there is a physical object, the cat, that causes what I see is the best explanation of my sense data
Scepticism about the nature of the external world (counter for indirect realism)
We have assumed so far that in talking about the external world, we are talking about physical objects. But even if we can show that our sense data are caused by something that exists independent of our minds, can we establish what kind of thing that cause is? We can’t tell what a cause is like just from its effects. For example when u see smoke do you know that fire caused it?
Locke’s primary and secondary qualities (reply to scepticism about the nature of the external world)
Primary qualities are qualities that are ‘utterly inseparable’ from the object whatever changes it goes through, even if it is divided into smaller pieces. They are shape, motion, number and solidarity.
Secondary qualities are qualities that physical objects have that are nothing but powers to produce various sensations in us. They are colours, sound and taste
The distinction between the qualities is what the quality actually has in themselves and what is related to how they are perceived.
Berkeley’s idealism
The immediate objects of perception are mind dependent objects
1) thorough vision, we perceive colours, shapes, size etc; through hearing, sounds; through smell, odours - and so on. Each sense perceived particular types of qualities
2) when we perceive physical objects, we don’t perceive anything in addition to its primary and secondary qualities
3) therefore, everything we perceive is either a primary or a secondary quality
4) both primary and secondary qualities are mind dependent
5) therefore, nothing that we perforce exists independently of the mind: the objects of perception are entirely mind dependent.
Berkeley’s master argument (supporting argument for idealism) and reply
Philonous challenges hylas to think of an object that exists outside of the mind. Hylas then says he is thinking of a tree existing unperceived by anyone. Philonous objects and says what he is thinking depends on his mind. He isn’t actually thinking of a tree exists independently of any mind, he is imaging a tree standing in a solitary place where no one perceives it.
Reply:
1) thoughts cannot exist outside of the mind - thoughts are psychological events or states
2) therefore, my thinking of a tree is not mind independent. It is impossible is that there is a thought of a tree when no one is thinking of a tree
3) but what a thought is about, is not the same thing as the thought itself
4) therefore, just because my thinking of a tree is mind-dependent, it does not follow that what I am thinking of is also mind dependent. It is not impossible to think that a tree may exist when no one is thinking of it
Idealism does not give an adequate account of illusions and hallucinations (counter for idealism) + reply
Berkeley discusses these, in the form of dreams on page 45. Hallucinations are products of imagination. Normally, imagination is voluntary and perception is not. But hallucinations are involuntary, so Berkeley provides two criteria that mark off hallucinations from perception.
First, they are ‘dim, irregular, and confused’. Second, even if they were as ‘vivid and clear’ as perceptions, they are not coherently connected with try rest of our perceptual experience.
To this we might object that these criteria mark a difference of degree - perceptual experiences can be more or less clear or dim, more or less coherently connected with other experiences. But surely the different between hallucination and perception is a different kind. In perception, you experience something that exists outside your mind, in hallucination, you don’t.
In response, Berkeley could agree - the ideas you perceive originally in God, but in hallucination they don’t. His criteria are only supposed to indicate how we can tell.
Solipsism
This is the view that only oneself, one’s mind, exists.
Idealism leads to solipsism (counter argument for idealism and reply)
We can object that Berkeley’s four arguments against mind independent objects - starting from the claim that everything I perceive is mind dependent - lead to the conclusion that all that exists is my own experience. Or at least, experience gives no reason to believe that anything apart from my experience exists. * If all the I perceive are ideas, what reason do I have to think that other minds exist? For that matter, what reason do I have to think that mind exist? After all I do not perceive minds.
Reply from Berkeley:
1) the mind is that which perceives, thinks and wills, while ideas are passive
2) I am aware of myself as capable of this activity
3) therefore, I am not my ideas, but a mind
4) being a mind myself, I have a ‘notion’ of what a mind is
5) therefore, it is possible that other minds exist
6) my perceptions don’t originate in my mind
7) therefore, they are caused by some other mind
8) the complexity, regularity, etc, of my experience indicates that this mind is God
Acquaintance knowledge
This is knowledge of someone of some place. For example, I know Oxford well.
Ability knowledge
Knowing how to do something.
For example, knowing how to ride a bike
Propositional knowledge (what the course focuses on)
Knowledge that a claim (proposition) is true or false