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Flashcards in scepticism Deck (9)
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what is the closure principle?

if s knows that p and p entails q then s entails q


what is the skeptical argument?

If S does not know she is not a brain in vat then S's knowledge is clearly limited
S does not know she is not a brain in vat
S's knowledge is clearly limited.
How can we say we know anything?
The radical skepticism answer is that we do not as we can doubt all our knowledge - there is no certainty


why is skepticism an unpopular position?

If we cannot know anything, what is the point?
Highly counter-intuitive to common sense.


How does Moore respond to the problem of skepticism?

Appeals to common sense.
aims to turn a skeptical modus ponens into an anti-skeptical modus tollens.
1- if S does not know she is not a brain in vat, then S does not know she has hands
2- S does not know she is a brain in vat
C- S does not know she has hands.

1- If S doess not know she is not a brain in vat then S does not know that she has hands
2- S does know that she has hands
C- S knows she is not a brain in vat

or more commonly put
1- here is my right hand
2- here is my left hand
3- there exists at least two objects in the external world
C- an external world exists

- Moore says for his argument to work he needs to
1- have his premises follow to his conclusion
2- premises and the conclusion cannot be the same
3- premises must be known to be true


PODGORSKI's objection to Moore?
further reply?

Premises are not demonstrable
-the truth of Moore's premises lie in being observable by the demonsration that we have limbs
- this is through our observation and therefore our senses
- a skeptic can surely just doubt our senses and argue that empiricial demonstration does not constitute knoweldge.
Support - illusions , dreaming, hallucinations.

- we cannot explicitly prove that we are not in a hallucination and we cannot explicitly prove that this is reality. However, to not accept the appearence we are presented with is counter intuitive

further reply - to not question our reality is counter intuitive!


What is the criticism of Moore surrounding intuition?

Moore relies on the arguably strong intuition that we have hands leading to the conclusion that as this truth is so obvious an external world exists.
This defence of intuition could fuel a skeptical argument. If a skeptic had an equally strong intuition that they do not have a hand, this could lead to the equally strong conclusion, by the same Moorean logic, that the external world does not exist.


What is Wittgenstein's criticism of Moore?

To say you have knowledge of something is to presuppose that you have sufficient justification for it.
To say you have knowledge of an obvious truism like ' i have hands' presupposes the ability that this can be sufficiently justified in a way invulnerable to skepticism.
The evidence and justification for an obvious truth like this must be stronger / more certain than the actual beleif itself.
Crucially however, this cannot be the case as there is nothing more obvious than the fact we have hands.


Does Wittgenstein defend skepticism? what is his conclusion?


hinge propositions.
'the questions that we raise and the doubts that we have depend on the fact that some propositions are exempt form doubt, as it were like hinges on which those turn'
- we cannot investigate everything so we must be content with the assumption -if i want the door to turn the hinges must stay put!

reply - it may be pragmatic not do doubt, but it doesn;t mean we shouldn't - what if we uncover a matrix style scenario?


what do we say about knowledge?
reply ?
further reply?

knowledge is infallible - justified true belief that is infallible.
Unger - nothing is ever really known to an agent as for it to be known, every possibility would have to be ruled out and this is impossible given that we are fallible beings.

often dismissed as counter-intuitive to empirical development and research - all empirical progress would not matter if it does not consititute knoweldge. The status of synthetic knowledge would be undermined. This sets the bar too high for knowledge

reply - just because something is not 'knowledge', it does not follow that all empirical research and progress is redundant. You can say we will never have knowledge/certainty of something but as this cannot be proven/disproven, we should support the claims useful in our lives e.g. science.