Perception As A Source Of Knowledge - Indirect Realism

Question 1

Define Indirect realism

Answer 1

Indirect realism claims that we perceive physical objects which are mind independent but we do so via, or in virtue of, perceiving mind dependent sense data that are caused by and represent physical objects.

Question 2

What are sense data?

Answer 2

Russell defined sense-data as the content of perceptual experience.
1. Sense data are mental things which are the way we perceive them to be.
2. Sense data only exist while they are being experienced. An experience must be experienced by someone to exist at all. Physical objects can exist when no one experiences them
3. Sense-data are private. No one else gets to experience your sense data. physical objects are public and the same object can be experienced by different people.

Question 3

What are the arguments against direct realism which argue for indirect realism?

Answer 3

The argument from perceptual variation
Argument illusion
Argument from hallucination
Time lag argument

Question 4

Outline Locke’s distinction between primary and secondary qualities

Answer 4

Locked, defended a form of indirect realism as a part of his theory he argued that we can distinguish the qualities that we perceive into two kinds:
- Primary qualities
- Secondary qualities

Question 5

Define ‘a quality’

Answer 5

The quality is a power that a physical object has ‘to produce an idea in our mind’.
For example, a snowball has the powers (the qualities) to produce ideas in us like : cold, white, round.

Question 6

What are primary qualities?

Answer 6

Primary qualities are ‘utterly inseparable from the object’ whatever changes it goes through.
For example dividing into smaller and smaller pieces.
The object has these qualities ‘in and of itself.’

Question 7

What are secondary qualities?

Answer 7

Qualities that physical object has that are nothing but ‘powers to produce various sensations in us’
For example, colours sounds and tastes.

Look later adds smells and temperature.

Question 8

What is the key distinction between primary and secondary qualities?

Answer 8

Primary qualities also produced sensations in us, but they are qualities that the object has whether or not we perceive it, hence they are mind independent.
Colour, a secondary quality, for example, is a quality that an object can only have in relation to it being seen by someone, hence it is mind dependent

Question 9

What does Locke say about our perceptual experiences of primary qualities and the primary qualities of the object?

Answer 9

Locke says that our perceptual experiences of primary qualities ‘resemble’ the primary qualities of the object.

Question 10

What does Locke say about qualities and resemblance?

Answer 10

He says that a primary quality gives rise to an idea which resembles it. Secondary qualities give rise to ideas but the ideas are not like the qualities that give rise to them.
For example, colour is caused by light which can be explained in terms of the effects and activity of subatomic particles which is unlike what we perceive.
(So secondary qualities as we perceive them are nothing like what they are in the object, namely microscopic effects of the primary properties of atoms and molecules.)

Question 11

Why does indirect realism face the problem with scepticism?

Answer 11

Russell ends his argument in favour of sense data in chapter 1 creating a puzzle…
if what we perceived directly are sense data, then all we know about are sense data.
If we only perceive sense data and not the object itself, how can we know about anything in the external world?

( There is no way of telling if the data is an accurate representation of the external world or even if there is an external world at all. )
—-> SCEPTICISM

Question 12

What is scepticism?

Answer 12

Scepticism is the view that we cannot know particular claim in this case the claim that physical objects exist.

Question 13

How does scepticism create problem for indirect realism?

Answer 13

Since indirect realism means we cannot go beyond the veil of perception (sense data) we cannot know that physical objects exist. If we cannot know physical objects exist then we cannot know that sense data are caused by physical objects.
Therefore if indirect realism is true, we cannot know that it is true.

Question 14

What are Russell’s two responses to attempt to avoid the sceptical challenge?

Answer 14

1. Other people exist.
2. Best Hypothesis.

Question 15

Outline Russell’s first argument in response to scepticism

Answer 15

P1) the fact that sense data is private means that two people can actually never perceive the same thing, unless we can say that there are physical objects that they both perceive (indirectly).
P2) people have very similar sense data if they are at the same place and the same time
P3) the best explanation for this is that there are physical object causing their sense data : they both perceive the same physical object
C1) so physical objects exist

Question 16

Why does Russell reject the argument that physical objects must exist because people have similar sense data?

Answer 16

Russell reject this argument because it assumes something that we cannot know: that there are other people.
To assume that there are other people is to assume that physical objects exist so this cannot answer the question: does my sense data show that I know that there are physical objects?

Question 17

What is Russell second argument for the existence of in mind? Independent objects? (Best hypothesis.)

Answer 17

P1) either physical objects exist and cause my sense data or physical objects do not exist and do not cause my sense
P2) I can’t prove that either claim is true or false
C1) therefore I have to treat them as hypothesis
P3) hypothesis that physical objects exist and we perceive their sense data is better*
C2) therefore, physical objects exist and cause my sense data.

Question 18

Why does Russell argue that it is a better hypothesis that physical objects exist?*

Answer 18

Cat example
If I see a cat first in the corner of the room and then later on the sofa then, if it 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 don’t see it. It springs into existence in the corner, and then later on the sofa. Nothing connects my perceptions which is incredibly puzzling.
Therefore, the best hypothesis, is that there are physical objects that caused my sense data.

Question 19

Looks argument from the involuntary nature of our perception
(supporting argument for indirect realism)

Answer 19

• I cannot avoid having certain sense data produced in my mind
• by contrast if I turn from perception to memory and imagination e.g. By shutting my eyes, I find that I can choose what I experience.
• perceptual experiences - which ‘I have whether I want them or not’ must be produced in my mind by some exterior cause, namely physical objects.

Question 20

The argument from coherence of the various kinds of experience (supporting argument for indirect realism) LOCKE

Answer 20

Locke notices that our different senses confirm the information that each supplies. If I see a fire and doubt whether it is real, I can confirm it’s real by touching it.

Question 21

The argument from coherence of the various kinds of experience (supporting arguments for indirect realism) COCKBURN

Answer 21

Trotter Cockburn notices that one and the same object causes different perceptual experiences e.g. I see a dog and here its bark with the association made we can accurately infer one experience to another just seeing a dog, we know what it will make.
—> why would we be able to either confirm our experiences using our different senses or be able to predict them, unless there is something which both senses perceive that is independent of being perceived by any particular sense?
—> mind independent objects exist

Question 22

Outline Locke’s example about paper that aims to prove that the senses confirming each other

Answer 22

• I know from experience that I change how piece of paper looks by writing on it
• I can plan to write and I know in advance what the people will look like if I did
• But I cannot bring about the sense of seeing the paper with the words on it just by my imagination, I have to actually write it
• Once I have written something, I cannot change it.
• This shows that aren’t merely things of my imagination
• Finally, if someone else reads the words aloud, what I hear corresponds to what I intended to write
  C) this leaves very little reason for doubt that the words as written on a piece of paper exist independent of my mind mind.

Question 23

What is the problem with Locke and Cockburn’s arguments?

Answer 23

Look claims to have shown that mind independent objects exist and there must be some external cause of sense data.
But actually, both him and Cockburn present the same argument as Russell and strengthening it by adding a few features of experience that need explaining, but this still doesn’t make the existence of mind independent objects certain.

Question 24

What is Berkley’s argument that mind independent ideas cannot be like-minded independent objects?

Answer 24

(Context: Locke claims that primary qualities in the objects resemble our experience of them. For example the squareness of a physical object resembles the square as we see, Berkeley questioned whether that makes sense.)
- the argument from perceptual variation notes that our sense data changing depends on the conditions of the perception but the physical object does not change
- Furthermore we constantly split our eyes from one thing to another so we experience any changes but again, we know that the physical object does not change
Therefore the objection is how can our sense data, which are ‘perceptually fleeting and variable’, be ‘like’ or ‘resemble’ a physical object that is ‘fixed and constant’?

Question 25

What do indirect realists other than lock believe about the relationship between sense and the physical objects themselves?

Answer 25

Argue that sent data represent physical objects (just not by resembling them) the pattern of causal relations between the external world and our sense data is very detailed and systematic.