Gettier and the Theory of Knowledge

Synopsis

-Theory of Knowledge Before Gettier

- Gettier 's Challenge

-Response: Gettier 's Criticism Fails

-Response: Gettier 's Criticism Succeeds, but Modifications can be made to the Theory of Knowledge

Theory of Knowledge Before Gettier

Plato (428-328 B.C.)

"...an account added to true belief yields knowledge in its most perfect form." ( Theaetetus 206c )

Rodrick Chisholm

S knows that P

IFF

( i )	S accepts P,

(ii)	S has adequate evidence for P, and

(iii)	P is true. (Perceiving 1957, p.16)

Gettier 's Thesis (1963)

-Justified, True, Beliefs are Necessary but not Sufficient Conditions for Knowledge

Method

-Provide Clear-cut Counterexamples to the Definition

-Conditions Hold, but no Knowledge

Counterexamples

-Case 1: Smith's Belief That the Man Who Will get the Job has Ten Coins in his Pocket

-Case 2: Smith's Belief that Either Jones Owns a Ford, or Brown is in Brest- Litovsk

Possible Responses

Kenneth stern, robert meyers , d.m. armstrong

-Counterexamples Falsely Suppose That One Can be Justified in Holding a Belief on the Basis of False Evidence.

-This Appears Both Too Strong And Too Weak.

Too Strong: The Crow

Suppose that I come to believe that many crows are black based upon thousands of observational beliefs that I form individually to the effect "There is a crow, and it is black." Now, for all but one of them I am correct. In that one case, someone painted a seagull black. Now, do I really not know that many crows are black?

Too Weak
Counterexamples Without False Beliefs

Richard Feldman

-Smith's Belief That Someone in his Office Owns a Ford

Alvin Goldman/Carl Ginet

-Smith's Belief That he sees a Barn

Three Other Approaches

Defeasibility

Keith Lerher , Tom Paxton, and Rodrick Chisholm

-The Counterexamples Work. Knowledge is Actually Justified True Belief With No Undefeated Defeaters.

Too Strong

-Cognitive Relevance?

-Possible at all?

-Covert Requirement of Omniscience?

Conclusive Reasons

Fred Dretske

S knows that p, if S has a reason, R, such that if p were false, S wouldn't have R.

Too Weak

Could I know that there was a cup on the table if it was causing me to see a hologram of a cup?

Too Strong

Rules out all knowledge based upon high probability

Causal Accounts

Alvin Goldman

-Knowledge is Belief Where "...the fact p is causally connected in an 'appropriate' way with s's believing p."

Gettier and the Theory of Knowledge

Synopsis

-Theory of Knowledge Before Gettier

- Gettier 's Challenge

-Response: Gettier 's Criticism Fails

-Response: Gettier 's Criticism Succeeds, but Modifications can be made to the Theory of Knowledge

Theory of Knowledge Before Gettier

Plato (428-328 B.C.)

"...an account added to true belief yields knowledge in its most perfect form." ( Theaetetus 206c )

Rodrick Chisholm

S knows that P

IFF

( i )	S accepts P,

(ii)	S has adequate evidence for P, and

(iii)	P is true. (Perceiving 1957, p.16)

Gettier 's Thesis (1963)

-Justified, True, Beliefs are Necessary but not Sufficient Conditions for Knowledge

Method

-Provide Clear-cut Counterexamples to the Definition

-Conditions Hold, but no Knowledge

Counterexamples

-Case 1: Smith's Belief That the Man Who Will get the Job has Ten Coins in his Pocket

-Case 2: Smith's Belief that Either Jones Owns a Ford, or Brown is in Brest- Litovsk

Possible Responses

Kenneth stern, robert meyers , d.m. armstrong

-Counterexamples Falsely Suppose That One Can be Justified in Holding a Belief on the Basis of False Evidence.

-This Appears Both Too Strong And Too Weak.

Too Strong: The Crow

Too Weak
Counterexamples Without False Beliefs

Richard Feldman

-Smith's Belief That Someone in his Office Owns a Ford

Alvin Goldman/Carl Ginet

-Smith's Belief That he sees a Barn

Three Other Approaches

Defeasibility

Keith Lerher , Tom Paxton, and Rodrick Chisholm

-The Counterexamples Work. Knowledge is Actually Justified True Belief With No Undefeated Defeaters.

Too Strong

-Cognitive Relevance?

-Possible at all?

-Covert Requirement of Omniscience?

Conclusive Reasons

Fred Dretske

S knows that p, if S has a reason, R, such that if p were false, S wouldn't have R.

Too Weak

Could I know that there was a cup on the table if it was causing me to see a hologram of a cup?

Too Strong

Rules out all knowledge based upon high probability

Causal Accounts

Alvin Goldman

-Knowledge is Belief Where "...the fact p is causally connected in an 'appropriate' way with s's believing p."