Zusammenfassung der Ressource
Philosophy AS - epistemology
- 1. Perception
- What is
perception?
- (DR) Direct realist
- (IR) Indirect realist
- 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.
- We perceive sense-data immediately, and physical objects
indirectly.
- John Locke - primary (PQ) and
secondary qualities (SQ)
- (SQ) Secondary
qualities exist due
to sense-data being
perceived to
'produce various
sensations in us by
their primary
qualities.’.
- Clolour, temperature,
taste etc
- (PQ) Primary qualities are
the properties an object
holds mind -independently
of perception, qualities
that exist despite our
presence. A primary
quality exists irrespective
of any changes made - the
primary qualities hold
these properties ‘in and of
itself’.
- extension, motion -
including rest, solidity etc.
- ‘The tepid bowl’ - water has
one temp (M-I,PQ) but heats
(SQ) the perception of heat is
M-D. Our senses perceive SQ,
they’re M-D. PQ (eg extension)
exists in an of itself, it’s M-I.
- Russell - IR sense-data and
perception
- Russell argues from an epistemological stance of indirect
realism; perception is achieved indirectly through
mind-dependent sense data. (This stands in opposition to the
view of direct realism: we perceive objects directly).
- 1. We have variations in our perception.
- 2. Our perception varies without corresponding
changes in the physical object we perceive. (eg the
desk remains rectangular, even if the way it
appears 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 don’t perceive objects directly.
- Issues:
- 1) leads to
scepticism
about the
nature of the
external world
- IR argues that a mind
independent world causes
mind dependent sense data
(e.g. PQ/SQ). But sense data
differs from perceiver to
perceiver. So, who's right about
the nature of the MI world?
Well, the skeptic argues no one
is right: we cannot know what
the world is like, I can only
know my sense data.
- 2) leads to scepticism about the
existence of the external world
- can we ever know the source
of sense data? How can I
prove an object and it's
properties really caused my
perception? Every attempt
will just be more sense data,
never it's supposed source.
- Berkeley - idealism
- If one were to apply Locke’s arguments against the
mind independence of the SQ to PQ, one would be a
Berkeleian idealist.
- 1. ‘The Master Argument’: Nothing can exist unperceived, esse is
percipi. (A tree for example, one cannot imagine a tree without it
being perceived - because wherever we imagine a tree we
imagine it from the point of view from some perceived. It is
impossible to imagine a tree from no perceiver's point of view.)
- 2. God perceives all.
- Rejecting Idealism:
- God's role in perception is questionable.
- The claim that everything I perceive is
mind dependent leads to the conclusion
that all that exists is my own experience.
It gives me no reason to believe that
anything other than my own mind exists,
as all I perceive are Ideas.
- Solopsism
- All objects of perception are M-I and
are perceived directly; it obeys
Ockam's razor.
- (eg the reason I see the sky
to be blue is because the sky
possesses the property ‘blue’
which causes my perception to
have the same property.)
- Arguments against DR:
- 1) Russell's perceptual variation
- 2) Argument from illusion
- (The crooked oar.) Rather than directly
perceiving the stick, which would entail our
seeing it as it truly is, we must instead perceive it
indirectly, by way of an image or "sense-datum".
- This mental representation does not tell us anything
about the stick's true properties, which remain
inaccessible to us. With this being the case,
however, how can we be said to be certain of the
stick's initial straightness?
- If all we perceive is sense-data then the stick's
apparent initial straightness is just as likely to be
false as its half-submerged bent appearance.
Therefore, the argument runs, we can never gain
any knowledge about the stick, as we only ever
perceive a sense-datum, and not the stick itself.
- 3) Argument from Hallucination
- 1. We perceive something as having a property.; we
perceive this property so there must be a physical
object that has this property.
- 2. In a hallucination, we do not perceive a physical
object at all.
- 3. Therefore, what we perceive exists only in
the mind- sense data.
- 4. So, we perceive sense data in both
hallucinations and veridical perception.
- 5. Therefore, we only ever perceive sense
data immediately- not the physical objects.
- 6. Therefore, direct realism is false. We cannot
distinguish between empirical reality and
hallucination.
- 3) Time-lag
- 1. Visible light from our sun bounces off objects of perception and
strikes our retina, this is human perception as DR understand it.
- 2. Light from the sun is delayed by aprox 8 minutes.
- 3. Therefore we do not percieve the light immediatly.
- 4. Therefore, we do not percieve objects directly.
- I. Perception
- II. Knowledge
- Justified True Belief
- There are three components to the
traditional (“tripartite”) analysis of
knowledge. According to this analysis,
justified, true belief is necessary and
sufficient for knowledge.
- The Tripartite Analysis of
Knowledge:
- S knows that p iff
- i. p is
true;
- ii. S believes that
p;
- iii. S is justified in
believing that p.
- But is it always sufficiant for
knowledge ?
- Edmund Gettier - 'a Gettier case'
- Where one has JTB but fails to have knowledge
- Case study one:
- The case’s protagonist is Smith. He and Jones have applied for a
particular job. But Smith has been told by the company president that
Jones will win the job.
- Smith combines that testimony with his observational evidence of there
being ten coins in Jones’s pocket. (He had counted them himself — an odd
but imaginable circumstance.) And he proceeds to infer that whoever will
get the job has ten coins in their pocket.
- Notice that Smith is not thereby guessing. On the contrary; his belief b
enjoys a reasonable amount of justificatory support. There is the company
president’s testimony; there is Smith’s observation of the coins in Jones’s
pocket; and there is Smith’s proceeding to infer belief b carefully and
sensibly from that other evidence. Belief b is thereby at least fairly well
justified — supported by evidence which is good in a reasonably normal way.
As it happens, too, belief b is true — although not in the way in which Smith
was expecting it to be true. For it is Smith who will get the job, and Smith
himself has ten coins in his pocket.
- These two facts combine to make his belief b true. Nevertheless, neither of
those facts is something that, on its own, was known by Smith. Is his belief b
therefore not knowledge? In other words, does Smith fail to know that the
person who will get the job has ten coins in his pocket? Surely so (thought
Gettier).
- It contains a belief which is true and justified — but which is not knowledge. And if
that is an accurate reading of the case, then JTB is false. Case I would show that it is
possible for a belief to be true and justified without being knowledge. Case I would
have established that the combination of truth, belief, and justification does not
entail the presence of knowledge. In that sense, a belief’s being true and justified
would not be sufficient for its being knowledge.
- Rejecting Gettier:
- Virtue epistemology
- You know p is true if;
- p is true;
- s believes in p;
- and s's true belief is the result of them
exercising their intellectual virtue.
- If you use your intellectual virtues to find
knowledge then that knowledge is a
cognitive achievement
- Sosa
- Invented virtue epistemology
- If you imagine an archer aiming
at a target, it is like a person
aiming to know something
about the world
- AAA structure are both necessary and jointly
sufficient for Knowledge
- 1A. Accurate
- Do you hit the
target? Do you
have the right
beliefs about the
right thing? Is
what you're
thinking true?
- 2A.
Adroitness
- Did you aim and
shoot well? Did
you do it right -
as an exercise of
intellectual
faculty? As the
name suggests,
did you use the
right skill?
- 3A.
Aptness
- Did you form your
conclusion from
1A and 2A? Or
was it just fluke K
(Gettier)? It is
accurate due to
your adroitness.
- This defeated Gettier
as his 'cases' held
only A1 and A2, was
simply fluke
Knowledge
- III. The origins of knowledge and concepts
- Knowledge
- Synthetic
- A synthetic proposition is
one that is not analytic,
i.e. it is true not in virtue
of the meanings of the
words, but in virtue of the
way the world is
- Analytic
- An analytic
proposition is true
or false in virtue of
the meanings of the
words
- A priori
- knowledge that does
not require (sense)
experience to be
known to be true
- Relations of ideas
- a proposition which is
mathematical or logical.
It is rationally certain
but tells us nothing
about reality
- A
posteriori
- knowledge that
requires (sense)
experience to be
known to be true
- Matters of fact
- a proposition which is
empirically verifiable. It
tells us about the real
world.
- Is all a priori knowledge knowledge
of analytic propositions? Are all
synthetic propositions known a
posteriori?
- Rationalism
- NO
- we can have a priori
knowledge of synthetic
propositions E.g.
through reason or
innately.
- Empiricism
- YES
- if a proposition is not
made true through logic
or meaning; it can only
be established by sense
experience.
- Contingent and Necessary
- A truth represents a true statement
whose negation must imply a
contradiction in reality, such that the
negation would be impossible
- A contingent truth, or falsehood, concerns
something that could have been otherwise. A
proposition that expresses a contingent truth
can be rationally denied without resulting in
any self-contradiction.
- See Diagram
- Infallibilism
- Instead of destroying JTB, it
attempts to preserve it by
improving the J.
- It does this by:
- s believes p;
- p is true;
- s is justified in believing p IFF s can't
be mistaken, thus your J results in
certainty.
- Flaws in infallibilism:
- 1. It ends in very little knowledge
- To say you know something you
have to be ultimately certain,
which results in little 'knowledge'
- 2. If you think you know
something you also
believe you are certian
- 3. People want to
say 'I know' but can't
with this theory.
- So, humans want to be able to
say they know something but
this theory leave very little to
know.
- 4. Only super human epistemology
works, as only superhuman
knowledge (beings) can be certain.
- Reliabilism
- Reliabilism claims that you know that p if
- p is true;
- you believe that p;
- your belief is caused by a
reliable cognitive process.
- Disadvantages: 1. Reliable
methods can easily lead to
falsehoods. (ie: 'I saw a dragon,
therefore it's real')
- Advantage: of reliabilism is that
it 1. allows young children and
animals to have knowledge.
- 2. It allows for knowledge to
become broad in terms of how
much we can be certain of
knowledge
- 2. Justification can often be
explanatory, it destroys JTB by
taking out the justification, but
reliable methods don't always
tell you why, how or when
something works.
- 3. You can just as easily
believe a false proposition as
a true one, due to the lack of
certian justification