StarterInternalism vs. Externalism

• Internalism - justification is solely determined by factors that are internal to a person.– Q. – ‘What counts as external to a person?’

• Externalism - the internal justification condition is replaced by an external knowledge-generating factor. It depends on additional factors that are external to a person.

Responses to Gettier

Gettier’s Method• Devised unusual counter-examples to the JTB

account– JTB = iff X has a justified true belief that p, X thereby

knows that p– Gettier cases = cases in which I have justified true

belief, but claim to knowledge seems peculiar– ‘cases of lucky true beliefs show that the justification

condition should be either strengthened, added to or replaced’

– JTB is proven to be necessary but not sufficient, so• Either additional condition needed • or J needs revision somehow

Responses to Gettier

1.add a ‘no false lemmas’ condition (J+T+B+N) 2.strengthen the justification condition:

infallibilism and the requirement for an impossibility of doubt (Descartes)

3.replace ‘justified’ with ‘reliably formed’ (R+T+B) (reliabilism)

4.replace ‘justified’ with an account of epistemic virtue (V+T+B)

Inference

• To infer = to work one thing out from another thing.

• A successful argument is made of a sequence of linking steps or inferences.

Step 1• God exists

Step 2• And God isn’t a

deceiver

Step 3

• So I can trust my senses (when they are checked by my intellect)

Step 4• They tell me the

external world exists.

Steåp 5• And so the external

world does exist!

Adding an additional condition: ‘No false lemmas or premises’

• A premise is a starting point in an argument or proof

• A lemma = a subsidiary or intermediate theorem in an argument or proof

• Gettier problems: here, conclusion is based on mistaken intermediate theorem, although conclusion is correct.

• So: ruling out false lemmas would rule out Gettier problems.

‘No False Lemmas’ in Standard Form

S knows that P iff1. 1. S believes that p 2. S is justified in believing p. 3. P is true. 4. S‘s justification is not based on a false premiseOR

S did not infer P from a false lemma

Clark, M., 1963. “Knowledge and Grounds. A Comment on Mr. Gettier's Paper,” Analysis, 24: 46–48. (also - Armstrong, D. M., 1973. Belief, Truth, and Knowledge, C.U.P.)

False Lemmas in more detail• Gettier gets us to agree that

1) ‘…it is possible for a person to be justified in believing a proposition that is in fact false. ‘2) ‘for any proposition P, if S is justified in believing P, and P entails Q, and S deduces Q from P…then S is justified in believing Q.’

• The false lemma in Gettier’s argument‘P: Jones is the man who will get the job, and Jones has ten coins in his pocket. Proposition P entails Q: The man who will get the job has ten coins in his pocket.’

• Here, P is false, although Q is true. • So ruling out false lemmas would rule out Gettier’s

counter-example.

Why might these images be relevant to what has just been discussed?

Problems with the ‘No False Lemmas’ condition

• The extra condition deals with cases where S infers that P based on a false lemma.

• But some knowledge = perceptually direct or non-inferential– Put another way: you believe what you perceive – you don’t have to infer

what it is that you are perceiving (‘I need a wee’…)– And if perceptually-based knowledge-claims were rephrased inferentially,

no false lemmas would be involved. (‘It appears to be a duck. I normally trust my senses. So it is a duck’)

• Which means that Gettier counter-examples can be devised where you don’t make an inference (so there are no false lemmas)…yet you still don’t have knowledge.

• Alvin Goldman’s 1975 article ‘Discrimination and Perceptual Knowledge’ gives the famous ‘Barn County’ example.

The Barn County Example (Alvin Goldman, 1976)

‘Henry is driving in the country-side with his son. For the boy's edification Henry identifies various objects on the landscape as they come into view. "That's a cow…that's a tractor…that's a silo, that's a barn," etc. Henry has no doubt about the identity of these objects; in particular, he has no doubt that the last-mentioned object is a barn, which indeed it is. […] Suppose we are told that, unknown to Henry, the district he has just entered is full of papier-mâché facsimiles of barns. […] if the object on that site were a facsimile, Henry would mistake it for a barn. Given this new information, we would be strongly inclined to withdraw the claim that Henry knows the object is a barn. How is this change in our assessment to be explained?’

What’s the difference between example 1 and 2?

Example 2(1) Roderick is pretty clever(2) Even clever students must

study for hard tests. (3) But he doesn’t have much

time to study because of his job.

(4) So we can predict that he won’t do well.

(5) It follows thus he will feel disappointed.

This is not Roderick

Example 1

The ‘Barn County’ example, explained

• Remember: Henry is excellent at identifying barns non-inferentially.– So if he identifies something as a barn, he knows. – Yet he’s driving through a strange county where there are many fake barns, and

some real ones.– So if Henry saw one of the fake ones, he would mistake it for a barn. – And hence even if Henry actually were to see a real barn, we would not say

that he knows that what he sees is a barn (because he would not be able to reliably tell which was which, real or fake).

• So our view of whether Henry knows that what he sees is a real barn has changed.

• ..even though Henry has justified true belief that is not inferred from any false lemmas.

• So we can immediately conclude: the ‘No False Lemmas’ condition is shown by Barn County to be inadequate…

Task:

• Revisit your Gettier counter-example.• Consider your No False Lemmas

objection.• Does it still stand, or is the knowledge-

claim based on non-inferential knowledge?