In philosophy, the common definition of knowledge is that knowledge is a 'Justified True Belief'. As long as these three conditions (J, T, and B) are met, you can claim to have knowledge. But in 1963 Edmund Gettier published what is now called the Gettier problem, which seems to show that J, T, and B are not enough. *

You work in the office with a great guy called Mr. Nogot. In the past he has explained network cards and nuclear physics to you, and kept you informed of the donut count in the staff room. He has not lied to you, and you feel justified in trusting his word.

Today Mr. Nogot informs you that he is the proud owner of a new Ford car. At lunch, you see him drive off in a Ford. And while digging through the papers on his desk you come across the ownership papers to a Ford.

Because of all this, you form a justified belief that Mr. Nogot does indeed own a Ford. Because of this, you also form the belief that "someone in this office owns a Ford". (If you were asked who, you would say Mr. Nogot. But if simply asked if someone if your office owned a Ford, the answer would be yes).

But it turns out that Mr. Nogot was only fooling you... It's not his Ford he was driving, and those papers were forged. So you can no longer claim that you knew** that Mr. Nogot owned a Ford (Because it wasn't a justified true belief).

The next day you see your co-worker Mr. Havit in the parking lot, where he is parking his Ford. He, five reliable witnesses, and the parking attendant explain that he has had this Ford for the past year. You are convinced. You now have a justified true belief that Mr. Havit owns a Ford. And, therefore, that "someone in your office owns a Ford".

So... Did you know before this that someone in your office owned a Ford? You did have a justified true belief that someone did. It was justified for Mr. Nogot, and true for Mr. Havit, but it was clearly both justified and true. It just so happens that you were just basing that belief on false evidence.

So is justified true belief enough for knowledge? Even when it's based on false Ford ownership? And if it isn't enough for knowledge, what is required?

* This is not the original Gettier problem. I'm not exactly sure what form that took, but I think it involved Mr. Nogot and a Ferrari.

** You didn't have a justified true belief, and if you didn't have a JTB, you didn't 'know'--that is, at that point you didn't have knowledge. A possible problem here is that not all people have the same definition of 'knowledge', and that not all people use the word 'know' as only identifying an instance of 'knowledge'. In this case we have defined knowledge as a JTB, and we are using 'know' and 'knew' as forms of JTB.

original Gettier problem:

Suppose that Smith and Jones have applied for a certain job. And suppose that Smith has strong evidence for the following conjunctive proposition:

d. Jones is the man who will get the job, and Jones has ten coins in his pocket.

Smith's evidence for (d) might be that the president of the company assured him that Jones would in the end be selected, and that he, Smith, had counted the coins in Jones's pocket ten minutes ago. Proposition (d) entails:

e. The man who will get the job has ten coins in his pocket.

Let us suppose that Smith sees the entailment from (d) to (e), and accepts (e) on the grounds of (d), for which he has strong evidence. In this case, Smith is clearly justified in believing that (e) is true.

But imagine, further, that unknown to Smith, he himself, not Jones, will get the job. And, also, unknown to Smith, he himself has ten coins in his pocket. Proposition (e) is then true, though proposition (d), from which Smith inferred (e), is false. In our example, then, all of the following are true: (i) (e) is true, (ii) Smith believes that (e) is true, and (iii) Smith is justified in believing that (e) is true. But it is equally clear that Smith does not know that (e) is true; for (e) is true in virtue of the number of coins in Smith's pocket, while Smith does not know how many coins are in Smith's pocket, and bases his belief in (e) on a count of the coins in Jones's pocket, whom he falsely believes to be the man who will get the job.

for "Is Justified True belief Knowledge?" Edmund Gettier (1963)

my own example:

Father is working on the roof one day when walking past his daughter Sally's window he sees her with a sack of weed and a joint. Sally sees him in the window and rushes to hide the contraband. Her father logically assumes that she has been doing drugs. In reality, Sally found the sack in her brother Jimmy's room and had merely taken it back to her room to decide what she was going to do in light of her discovery. That night father calls a family meeting and announces, "Someone in this family has been using drugs." This belief is justified and true.
Ever since Plato, there's been an epistemological tradition of defining knowledge as true belief plus a reason. (He called it a Logos, but that's Greek for you.) This is what reduces to our common sense notion (used in science) that knowledge is justified true belief (where the justification process is now a scientific one.)

This was all thrown into chaos, when Earnest Gettier who was an American philosopher in the early 1960's (1963 to be precise I think) pointed out that while a person may hold a belief, and it may be true, and justified, but it may not relate to the truth in the right way. In other words it is relatively accidental, or it's just lucky the person is right.

This is counter intuitive when first heard, and so he furnished a series of examples, the aforementioned Gettier Examples, to illustrate his point. Lets say I reasonably and justifiably saw the Pope receiving a bottle of whiskey and thus rightly concluded that the Pontiff was a drinking man who enjoyed the occasional bottle of Jack's Best. Now the truth is that his holiness does, but on this occasion he was in fact taking delivery of a medical specimen for his dear aunt in Poland. Now in this case my belief is true, and justified, nevertheless I don't know that he drinks whiskey, since the truth is just accidentally relative to my belief. He could be a teetotaller.

As you can imagine, this sparked a long and furious debate over the kinds of conditions that could be put in place to offer a verifiable model of knowledge, or whether this was a futile exercise, and such a model couldn't in fact be said to exist at all. This debate was used to add fire to the philosophies of relativism, nihilism, and oddly enough some aspects of phenomenology. The logical positivists had a hard time with it as well, because they couldn't create a formal system that got around the notions, but they were to have enough troubles dealing with Godel.

The Gettier Problem essentially boils down to this: false beliefs (through the magic of deductive reasoning) can be used to justify true beliefs, which are therefore knowledge. This is bad because if the deducer had known that their original belief was false, they would not have been able to justify their new belief. In turn, this demonstrates that the concept of justification was much weaker and less intuitive than epistemologists had previously believed.

So the obvious next step was to slap a bandaid on JTB to get JTB+: knowledge is a true belief that is justified by true beliefs (or without reference to false beliefs). However, this turns out to suffer from problems when a belief is justified insufficiently but happens to be true by chance. For example:

Say you're watching a magic show and the magician puts a rabbit into his hat. Based on your true observations, you conclude "there's a rabbit in that hat". However it turned out that your eyes deceived you: it was a stuffed rabbit. But while you were making your deduction, the magician switched it for a real rabbit*, thereby making your belief true.

Your belief about the rabbit was justified and turned out to be true, but only by luck. So something's still wrong here, and I think this is just about the point in the history of epistemology where people started questioning truth and the whole JTB enterprise fell apart.

* What, you think it's a stupid trick? Well I didn't tell you the end yet, did I?!

Sufficient Contrary Evidence

It is difficult to gather sufficient evidence for knowledge under most circumstances; uncertainty is a fact of the human experience. While most philosophers do not bother with such sophistic arguments as the invalidity of empirical data, some do attempt to show that the standard understandings of knowledge – based on the definition that it is “justified true belief” – are sometimes insufficient, even with sufficient evidence. Gettier may be the most famous of these philosophers, an eponymous “problem” emerging in epistemology with the 1963 publication of his “Is Justified True Belief Knowledge?” The main flaw in Gettier’s argument in particular is that the provided “sufficient evidence” could not be considered sufficient under any circumstances, which is to say that his applications of standard models of knowledge to his examples show nothing of the models whatever. Actually, it might be said that, sometimes, what seems to be sufficient evidence for knowledge is evidence for the absence of knowledge. A powerful example of this is present in Gettier’s “Case 2”.

Case 2 turns on the proposition that “Jones owns a Ford”. There are two instances of evidence for this proposition provided by our protagonist, Smith: (i) Smith recalls on former occasions seeing Jones driving a Ford, and (ii) Jones only recently offered Smith a ride in a Ford. This, Gettier claims, in enough information to “justify” the original proposition. Of course, he claims that Jones does not own a Ford; maybe he had been borrowing a friend’s car, or renting, whenever Smith saw Jones in such a car. But one must be critical of Gettier’s provided evidence; could we ever call these two instances sufficient justification?

One can address both of these instances with the same premise, that seeing Jones in a Ford is not the same as Jones owning a Ford. One might ask, “What would be sufficient evidence for the knowledge that Jones owns a Ford?”, and this would not be easy to answer; the question of sufficient evidence is always a tricky matter, and is usually answered as practically as possible. Obviously, Jones claiming to own a Ford would not be enough. Maybe testimony from a salesman at the local Ford dealership, or some other third-party authority on car ownership – a body shop owner, or an insurance adjuster? Whatever one settles on, it is not present in this case.

The evidence present seems to reasonably direct Smith to the assumption that Jones owns a Ford, though an inspection of his evidence might actually make him suspicious of the veracity of this belief. According to (i), the recollection that Smith has is that Jones has driven (a) Ford(s); the car make is the singular memory that he has. And Smith just saw the car in which Jones is driving, which can be understood as long as it is agreeable that one deduces Smith’s sight of the car from (ii). Upon this sight, might Smith have noted that the car looked the same as he recalled, or looked different? And if so, would this similarity or difference be considered evidence for Jones’s ownership of a Ford? For, should the car look the same, it would reinforce the notion that Jones has had the same car for some tract of time (this would not provide sufficient justification for the belief that Jones owns a Ford, but it might provide some justification). And, should the car look different, it would be evidence contrary to the notion that Jones owns a Ford. Moreover, the notion that Smith’s only recollection of the car(s) Jones has driven appears to be evidence that the make is the most notable similarity amongst all of the cars that Jones has driven; and this hints, by my estimation, at the possibility that Jones has driven different cars of the Ford make. Of course, this could mean that Jones owns multiple Fords, and therefore that Jones does, indeed, own a Ford. However, should I be in Smith’s position, I might assume that he has rented the Fords from the same company; I suppose it would depend on my familiarity and history with Jones.

If Gettier demonstrates anything in “Is Justified True Belief Knowledge?”, it is that sometimes sufficient evidence for knowledge is extremely difficult to collect, and that in attempting to certify knowledge one must scrutinize evidence to the limit of practicality. While Gettier fails to debunk the standard formulae for knowledge in his paper, he still shows that they (these formulae) are only a very small part of the determination of whether something is known. How far would Smith have to go to justify his belief that Jones owns a Ford? Even this is impossible to say without real circumstances. Maybe Jones leases.

This is a response essay to Edmund Gettier's "Is Justified True Belief Knowledge?" It has been reviewed by my Theory of Knowledge professor, and his comment was that while I raise some reasonable points, my paper does not address the same sort of knowledge that Gettier's does. My argument attributes certainty to knowledge, and analytic epistemology does not. Having read Alvin Goldman's "A causal theory of knowing" and Lehrer's and Paxson's "Knowledge: undefeated justified true belief", it has become perfectly clear that this is the case. Let this essay serve as a commentary on the sometimes counter-intuitive nature of evidence; I hope that you do not take my strong language so seriously!

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