Indirect Realism Flashcards
What is the formal argument of indirect realism?
P1. There are many perceptual experiences in which what we experience are not the properties of physical objects.
P2. When we perceive something as having some property F, then there is something that is F
C1. In such cases, given that what we perceive is not the way the world is, what we perceive are sense-data.
P3. Such cases are subjectively indistinguishable from veridical perception.
P4. When two perceptual experiences are subjectively indistinguishable, they are perceptual experiences of the same thin.
P5. Nevertheless, except in hallucinations, it still make sense to say we perceive the world.
C3. Therefore, we perceive physical objects indirectly via sense data.
How does Locke define a quality?
-A ‘quality’ is a ‘power’ that a physical object has ‘to produce an idea in our head’. So a snowball has the powers- the qualities- to produce in us the ideas of ‘white’, ‘cold’ and ‘round’.
What does Locke say about primary qualities?
- He says that these primary qualities cannot be separated from a physical object. For example they must have size/shape, they must be still or in motion etc.
- By contrast, physical objects don’t have to have the secondary qualities of colour or smell, for example colourless odourless gas.
Is Locke’s analysis of primary and secondary qualities correct?
- Locke believed that when you break up physical objects, you get smaller objects which also have all the primary qualities.
- But physics has moved on, and sub-atomic particles aren’t like physical objects that we know in lots of ways.
- Many of them have some form of electrical charge and many of them can behave as much like packets of energy as like small bits of matter.
- We may want to change Locke’s definition of primary qualities to those qualities that physics tell us physical have ‘in and of themselves’.
What is Bertrand Russell’s first response to this. And why it fails.
P1. The fact that sense-data are private means no two people actually ever perceive the same thing, unless we can say that there are physical objects they both perceive (indirectly).
P2. People have very similar sense-data if they are at the same place and time.
P3. The best explanation of this is that there are physical objects causing their sense-data: they both perceive the same physical object.
C1. So physical objects exist
-Russel then rejects this because it begs the question. It assumes there are other people (who are physical objects) to prove that there are physical objects!!
What is Russell’s second stronger argument?
P1. Either physical objects exist and cause my sense-data or physical objects do not exist and do not cause my sense-data.
P2. I can’t prove either claim is true or false
C1. Therefore, I have to treat them as hypotheses.
P3. The hypothesis that physical objects exist and cause my sense-data is better. (This is essentially (p5) in the general argument for IR)
C2. Therefore, physical objects exist and cause my sense-data.
-use the cat on the sofa example
Overview of claims of sense data.
- We perceive physical objects which are mind-independent
- But we do so via, or in virtue of, perceiving mind-independent sense-data.
- Sense-data are caused by and represent physical objects.
- Therefore, we perceive sense-data immediately, and physical objects indirectly.
What is the challenge to sense-data from direct realists?
- Direct realists understands perception as ‘openness’ to the world, a direct awareness of mind-independent objects.
- If we perceive the world via sense-data, the immediate ‘content’ of what we perceive is mental.
- You can’t describe images without referring to physical objects.
- You should be able to describe it using just sense-data but you can’t.
- This is indirectly referring to Ockham’s razor.
- Therefore sense-data seems counter intuitive.
- If you require physical objects to describe and image, then why do we need sense data?
What are the contrasts of sense-data with physical objects?
Sense data:
- Mental things are just appearances, they are the way they appear to be!
- Sense data only exists whilst being experienced
- Sense data are ‘private’, no one experiences your sense data e.g. a colour
Physical objects:
- Physical objects appear directly from how they really are.
- Physical objects do not need an individual to perceive them
- The Physical objects are public everyone experiences the same e.g. a chair.
What is the problem of scepticism?
- A problem for indirect realism is that it leads to scepticism about the nature and existence of the external world.
- ‘What would be the difference to the perceiver if there was no physical world at all?’ The answer surely is nothing.
- If we only perceive sense data, and not the object itself, how can we know anything about the external world?
- We can’t get beyond the veil of perception l (sense data) to access the external world behind it. This leads to scepticism whether there is anything beyond this veil at all.
What is Russell’s reply to scepticism?
-As an indirect realist, Russell concludes that there is no way we can conclusively defeat this sceptical argument. However, he argues that the existence of a mind -independent external world is the best explanation for sense data.
What is Locke’s first reply to scepticism? And how does it fail/what is the sceptics response?
- Locke notes how he is unable to avoid having certain sense data produced in his mind when he looks at an object. By contest, memory and imagination allows him to choose what he experiences. Locke concludes from this that whatever causes his perceptions must be something external to his mind as he is unable to control these perceptions.
- However; even if Locke succeeds in proving ‘something’ external, he doesn’t succeed in proving that sense data is in any way an accurate representation of the external world. The sceptic could argue that this external world could be completely different from our perception and there’s no way we could know.
What is Locke’s second reply to scepticism? And how the sceptics might try and counter it.
- Locke argues that the different senses confirm the information of one another. For example, you can write something on a piece of paper and see the words. Then you can get someone to read the words out loud and thus hear the same information via a different source.
- But does this really succeed in defeating the sceptical challenge? The information you ‘hear’ may be equally misrepresentative of the external world as the information you see.
What is Berkeleys formal argument from perceptual variation against indirect realism?
P1. What looks small to me may look huge to a small animal
P2. What looks small from a distance looks large closer up.
P3. What looks smooth to the naked eye appears uneven under a microscope.
P4. If you look at a circle straight on, it looks circular. But if I’m looking at it from an angle
It looks elliptical. We see it differently but it doesn’t change.
P5. Even motion is constant. We measure the speed of motion by now quickly our minds work- to a creature that responds much faster than us, our fastest movements seem leisurely.
P6. In the case of colour, when an object appears to have many colours, depending on how it is perceived, we can’t say it has one real colour independent to how we perceive it.
C1. Therefore, (p1-p5) show that we can’t say that an object has one real shape or size of motion, independent of how it is perceived.
C2. Therefore, the primary qualities of objects are just as mind-dependent as secondary qualities.
