Tuesday, 27 March 2012

Outline of Gettier’s “Is Justified True Belief Knowledge?”


Gettier argues that the tripartite conception of knowledge—according to which an agent, S, counts as knowing that p just in case (i) P is true, (ii) S believes that p and (iii) S is justified in believing that p—provides us with an insufficient basis for knowledge.


STEP 1: Gettier describes himself as setting out to impugn the following three closely-related conceptual analyses of knowledge:

(a) S knows that P IFF (i) P is true,
(ii) S believes that P, and
(iii) S is justified in believing that P.

(b) S knows that P IFF (i) P is true,
(ii) S accepts P, and
(iii) S has adequate evidence for P.

(c) S knows that P IFF (i) P is true,
(ii) S is sure that P, and
(iii) S has the right to be sure that P.

Step 2: Gettier introduces two cases that he believes represent counterexamples to (a), (b), and (c).

Case I: Smith has the justified true belief that: “the man who will get the job has ten coins in his pocket”, but his belief is based on the premise that Jones, who has ten coins in his pocket, will get the job, when in fact it is Smith who will get the job and who also (unwittingly) has ten coins in his pocket.

Case II: Smith has the justified true belief that: “Either Jones owns a Ford, or Brown is in Barcelona”, but his belief is based on the premise that the aforementioned disjunction is made true by the fact that Jones owns a ford, when in fact Jones does not own a ford but it so happens that (unbeknownst to Smith) Brown is in Barcelona.


Insofar as the subject in Gettier’s examples, Smith, has a belief that is justified, supported by adequate evidence or has the right to be sure, Case I and Case II represent counterexamples to (a), (b) and (c), respectively.


1. Do you share the intuition that the subject in Gettier's examples, Smith, does not have knowledge?

2. Does the subject in Gettier’s examples, Smith, have the right to be sure? What would Ayer say about Smith’s reasoning?


Caleb R said...

I would agree with Gettier at first in stating that in the examples the subject, Smith, does not have knowledge. However, I also believe that this is not due to Smith's lack of understanding, but is a consequence of something outside of the definitions for the necessary and sufficient conditions for someone's knowing a given proposition; faulty evidence. In taking a closer look at Case II, Smith's underlying assumption is that (i) Jones does own a ford. Smith's whole conception of knowledge in this example is built upon the inferred fact that "strong" evidence is enough reason to believe that Jones owns a Ford. Of course as the case reads on, we find out that Jones does not own a ford and therefore Smith's very first preposition is false.

The important idea that I took away from Gettier is that even though one may have strong evidence, that is all they have; evidence. In order for a subject to have knowledge, there initial propositions must be factual/true, and that truth must be final.

Na'Quelle Davis said...

I also believe that Smith doesn't have knowledge, given Gettier's reasoning and examples.

But also, given Ayer's reasoning, the subject does have the right to be sure in these cases because he is basing his assumption off of evidence or reasons that have proved trustworthy in the past. Still, as Gettier points out, there is a significant gap between "justified true belief" or "having the right to be sure" and knowledge. There is a slight error in reasoning in both positions, but I feel that Ayer might say that Gettier's argument against "Knowledge as Having the Right to Be Sure" is based upon an unfounded assumption or simplification. Ayer could argue that Gettier is wrong in equating the third condition in the tripartite definition with the third condition in his own and then offer specific reasonings why the two lines are actually very different.

Benjamin Altshuler said...

Gettier's counterexamples do indeed indicate that the Justified True Belief has insufficient criteria for defining knowledge.

Gettier's proof is indeed laudable, but his examples are so synthetic that I question how completely these Cases with Smith debunk Ayer and others.

While the counterexamples adhere to logic, they stray from expected human behavior. When people reach conclusions, they do not substitute entities in their mental propositions as Smith does in Case I and they do not insert unnecessary logical connectives as Smith does in Case II. Looking past these fallacies, Smith is correct as far as he knows because he trusts the sources that provided the information in both Cases.

Although our three part definition fails, it is not Smith who errs, but the system of reasoning he employs. Gettier's paper, if anything, indicates the need for more precise grounding to knowledge.

Russell Buehler said...

I agree that Smith doesn't have knowledge, but I'm not sure what Ayer would say. That said, I don't actually care what his response would be (arguments matter, philosophers do not). I do agree with Na'Quelle, however, in that Gettier undermines a great deal of Ayer's argument, and I would even say that Ayer's position, as stated, becomes untenable in the face of Gettier's examples. I also strongly disagree with Benjamin's post above. Deviating from normal human behavior is not a `fallacy' and there is nothing wrong with Smith's reasoning; the problem is solely with the definition of knowledge. Moreover, Gettier's substitution of a logical connective and generalization aren't abnormal at all; the generalization given is carried out by just about everyone on a daily basis and the use of a logical or is simply a more rigorous way of representing the rather common English `or'.

Caleb's suggestion is dealt with in the next two readings, so I'll just leave it be.

Andrew Cely said...

I think all of us believe that Gettier has developed a well crafted argument that pretty much disproves Ayer's Justified True Belief as an infallible model for knowledge. I do agree with Benjamin though in the fact that some of his examples come off as rather inane and redundant. Gettier doesn't necessarily accomplish a lot in having Smith construct sentences that would naturally make him right whichever answer he picked based off of incorrect previous experience. I'm fairly certain that most people don't think or behave in such a way solely to make sure that they're right or correct in some situation. Otherwise I find it an accurate means of disproving the Justified True Belief idea.