Zusammenfassung der Ressource
AS philosophy indirect and direct arguments: epistimology
- The Time-lag argument - Indirect realism
- 1) Perception is dependent on information about the external
world reaching the brain, via the sense organs, and then being
processed there, all of which takes a finite amount of time,
however small.
- 2) Therefore, the content of one's perceptions always lags
behind the external world, however slightly.
- 3) Therefore, when perceiving changes in the external world
there will always be a difference, however small, between the
content of one's perceptions and the external world at the
same moment in time.
- 4) If there is a difference, however small, between X and Y at
the same moment in time, then X is not Y.
- 5) Therefore, the content of one's perceptions is not the
external world.
- 6) Perception is, by definition, the process by which one
experiences the external world, via the sense organs.
- 7) Therefore, if the content of one's perceptions is not the
external world itself, then it must at least be a representation
of it.
- 8.) If the content of one's perceptions is merely a
representation of the external world, and not the external
world itself, then the only conceivable location of that
representation is inside one's mind.
- 9) Therefore, the content of one's perceptions is merely a
mental simulation of the external world. In other words, what
one directly experiences as being 'out there' is in fact located
inside one's mind
- The argument for hallucination
- Indirect
- 1) There are perceptual experiences, such as illusions and
hallucinations, in which what we experience are not the
properties of physical objects.
- 2) When we perceive something having some property F, then
there is something that has this property.
- 3) In such cases, given that what we perceive is not the way the
world is, what we perceive are sense-data.
- 4) Such cases are subjectively indistinguishable from veridical
perception.
- 5) When two perceptual experiences are subjectively
indistinguishable, they are perceptual experiences of the same
thing. (This claim is the best hypothesis, given (4).)
- 6) Therefore, we always perceive sense-data (not just in cases
in which what we perceive is not the way the world is).
- 7) Nevertheless, except in hallucinations, it still makes sense to
say we perceive the world. In cases of both veridical perception
and illusion, the sense-data we perceive are caused by and
represent physical objects. This representation can be accurate
or inaccurate in certain ways – physical objects may be as they
appear to us, or they may differ in certain ways.
- 8) Therefore, we perceive physical objects indirectly, via
sense-data.
- Direct
- We can experience perceptual hallucinations – not just
visual ones, but auditory and olfactory hallucinations as
well.
- 1 In a hallucination, we perceive something having some
property F.
- 2 When we perceive something having some 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 perceptions.
- 6 Therefore, we see the same thing, namely sense-data, in both
hallucinations and veridical perception.
- 7 Therefore, in all cases, we see sense-data, and not physical
objects, immediately.
- The argument for illusion
- Direct
- 1) We perceive something having some property, F (e.g. a
stick that is crooked).
- 2) When we perceive something having some property F, then
there is something that has this property.
- 3) In an illusion, the physical object does not have the
property F (the stick is not crooked).
- 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.
- Truthful; veracious: veridical testimony.
- 7) Therefore, we 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.
- Indirect
- The argument for perceptual variation
- 1 There are variations in perception.
- 2 Our perception varies without corresponding changes in
the physical object we perceive. (For instance, the desk
remains rectangular, even as the way it looks to me changes
as I look at it from different angles.)
- 3 Therefore, the properties physical objects have and the
properties they appear to have are not identical.
- 4 Therefore, what we are immediately aware of in perception
is not exactly the same as what exists independently of our
minds.
- 5 Therefore, we do not perceive physical objects directly.
- Direct
- Indirect
- 1 There are variations in perception.
- . 2 Our perception varies without corresponding
changes in the physical object we perceive. (For
instance, the desk remains rectangular, even as
the way it looks to me changes as I look at it
from different angles.)
- 3 Therefore, the properties physical
objects have and the properties
they appear to have are not
identical.
- 4 Therefore, what we are immediately
aware of in perception is not exactly the
same as what exists independently of
our minds.
- 5 Therefore, we do not perceive physical
objects directly.