PERCEPTION - DIRECT REALISM

DIRECT REALISM + OBJECTIONS

external world

the world that exists outside of your mind.

subjective

something that is perceiver/mind-dependent.

objective

something that is perceiver/mind-independent.

direct realism

the objects that we immediately perceive are mind-independent objects and their properties.

what are 4 objections to direct realism

1) perceptual variation
2) illusions
3) hallucinations
4) time lag

perceptual variation as an objection to direct realism

Russell - the properties of an object that we immediately perceive, are not identical to the the properties of the object that exist independently of our minds. Therefore we do not perceive objects directly.

direct realist's response to perceptual variation as an objection

relational properties - we perceive the properties an object has from that angle/distance. These are mind-independent.

illusions as an objection to direct realism

the fact that our perception can differ from reality suggests that direct realism is wrong that we perceive mind-independent objects directly.

examples of illusions

eg. a pencil in a cup half full of water

eg. white dots appearing black on a white grid with a black background

direct realist's response to illusions as an objection

J.L Austin - the pencil illusion is caused by refraction.
refraction is a feature of the external world.
Therefore, refraction is mind-independent.
Hence, we are directly perceiving a mind-independent property.

evaluation of perceptual variation as an objection

relational properties (response) contradicts direct realism.
as R.P says that the object doesn't actually have the immediately perceived relational properties.

there cannot be proof that all perceivers will perceive the same R.Ps

response implies that objects have multiples R.Ps - unhelpful for finding one 'true' set of properties.

evaluation of illusions as an objection

some illusions eg. white to black dots illusion, are mind-dependent.
so what we directly perceive is not identical to what exists independently of our minds.

hallucinations as an objection to direct realism

perception without an object.
however, it can feel just as real as ordinary perception.

direct realist's response to hallucinations as an objection

hallucinations are akin to imagination.
imagination is not perception, so hallucinations aren't perception. they are a different mental state.

evaluation of hallucinations as an objection

you cannot differentiate between hallucination and perception while hallucinating.
the same part of the brain is used for visual perception as for hallucination.
hence they are akin.

time lag as an objection to direct realism

we do not perceive things as they appear in the precise moment.

examples of time lag

- we see the sun as it was 9 minutes ago
- we see lightning a few seconds before hearing thunder

direct realism's response to time lag as an objection

the speed of light and sound are features of the external world and hence, are mind-independent.
misunderstanding of what is meant by 'immediate' here - we mean unmediated rather than with reference to time.
we are directly perceiving the past 'as it was'

evaluation of time lag as an objection

- the objection is weak
- time lag for usual perception is irrelevant and insignificant.
- I also agree that its features are of the external world and hence mind-independent.

what are the 4 features of sense-data?

subjective
mental
infallible
private

indirect realism

the immediate objects of perception are mind-dependent objects that are caused by and represent mind-independent objects.

tertium quid

third thing

sense-data

mind-dependent objects we immediately perceive