Indirect Realism; Perception

Front 1

What does Indirect Realism claim?

Back 1

Indirect Realism claims that we perceive physical objects which are mind-independent, but we do so via perceiving mind-dependent sense-data that are caused by and represent physical objects. We perceive sense-data immediately and physical objects indirectly.

Front 2

Describe the argument from perceptual variation

Back 2

The argument from perceptual variation (an objection to direct realism) works in favour of indirect realism. It states that there are variations within our perceptions, but the perception varies without corresponding changes to the physical object, so therefore the properties physical objects actually have and the ones we perceive them to have are not identical. This means that what we are immediately aware of in perception is not the same as what exists independently of our minds and therefore we do not perceive physical objects directly.

Front 3

Describe the argument from illusions and hallucinations

Back 3

There are perceptual experiences, such as illusions and hallucinations, in which what we experience are not the properties of physical objects. In these cases, what we are perceiving is sense date- such cases are subjectively indistinguishable from veridical perceptions. Therefore, we are always perceiving sense-data, although it makes sense to say we still perceive the world as the sense data we perceive are caused by and represent physical objects (it may be accurate or inaccurate). Therefore, we perceive physical objects indirectly through sense-data.

Front 4

What are sense-data?

Back 4

Russell defines sense-data as the 'content' of my perceptual experience. The sensations I am immediately aware of. Sense-data is how things appear to us- they exist as part of the mind and private to each individual person. They only exist whilst they are being perceived (in contrast to physical objects which can exist when no one is perceiving them).

Front 5

Describe sceptisim about the existence of the external world

Back 5

To know that physical objects cause sense-data, we first have to know that physical objects exist. But how can we know this, when the only access we have to physical objects is through our sense-data? Some argue; because other people see the same thing. However, an objection to this would be- how do you know other people (physical objects) exist?

Front 6

Describe the external world as the best hypothesis

Back 6

There are two possibilities: either physical objects do exist and they cause my sense-data, or they do not exist nor do they cause my sense-data. There is no way for us to prove that either claim is true or false. This means we have to treat them both as hypotheses- and the one that claims physical objects do exist and do cause my sense-data is better. Therefore- physical objects exist and these are the things that cause my sense data.

Front 7

What is Russell's argument behind the claim that the hypothesis stating physical objects existing is the better one?

Back 7

Russell uses the example of a cat. If I see a cat in the corner of the room and then later on the soda, then if the cat is a physical object, it would have travelled from one space to other whilst I wasn't looking. Although, if there is not cat apart from what I see in my sense-data, then the cat does not exist when I am not looking at it, It springs into existence in the corner of the room and then again on the sofa; nothing connects my two perceptions. However, this is a puzzling concept and doesn't provide an explanation for why my sense-data are the way they are. Therefore, that hypothesis is the better one.