A TE against JTB

The original Gettier-problem

In a three-page paper titled Is Justified True Belief Knowledge? (1961), Edmund L. Gettier claimed to have struck at the very foundation of a then rather firm tradition in epistemology, a tradition which considered knowledge as justified true belief (JTB). What is interesting about this paper is that its method is “thought experimental” – if such an adjective may be used.

Since its publication, many have acknowledge the fair death of JTB and many have tried a rebuttal of the two thought experiments it contains (as it seems quite often to be happening with thought experiments). There are standard replies and standard replies to replies, a very good exposition of which can be found in the Wikipedia article on it. Let us first take a brief look at the article.

“Is justified true belief knowledge?”

Gettier first identifies an established account which defines knowledge by reference to three sufficient conditions:

S knows p iff (a) p is true, (b) S believes that p, (c) S is justified in believing that p

The two philosophers pointed towards are R. Chisolom & A. J. Ayer. To this move some have responded as follows:

According to the inherited lore of the epistemological tribe, the JTB [justified true belief] account enjoyed the states of epistemological orthodoxy until 1963, when it was shattered by Edmund Gettier... Of course there is an interesting historical irony here: it isn't easy to find many really explicit statements of a JTB analysis of knowledge prior to Gettier. It is almost as if a distinguished critic created a tradition in the very act of destroying it. (Plantinga, 1992)

This, however, is a problem epistemologists and maybe historians of philosophy must deal with. As far as the thought experiments are concerned, even if one philosopher advanced a theory of the sort – and the theory itself is not total bogus – then an inquiry into the debate itself is not a useless assignment.

Before the definition of “S knows p if (a) (b) and (c) hold”, Gettier introduces two priciples which will be used in the thought experiment.

(i) It is possible for S to be justified in believing a proposition p “that is in fact false”

(ii) If S is justified in believing p and p "→" q, then S is justified in believing q if S is the one making the deduction and if S is making the deduction from p.

Again, one might feel the need to claim that these principles are not immediately acceptable within the debate. I think a similar criticism applies to both. First, the subtle insertion of “in fact” in (i) is problematic. If p is “in fact” false, then S is “in fact” not justified in believing p – but only “apparently” or “as far as he knows”. It’s hard to tell whether this affects the thought experiments and their conclusion, but nevertheless a preliminary question could have been addressed: Does S know p if p is true (according to him) but false (according to us)?. Second, the possible ambiguity of “justified” appears in (ii): S might think he is justified in believing p and be really justified in believing in q. Again, I don’t know if these points affect the thought experiment, but I don’t think they’re completely irrelevant either.

John & Smith & coins & jobs

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.

(Before we move to the second one, let us notice the similarity between this thought experiment and a classic scenario depicted by K. Donnellan in his paper on Reference and definite descriptions (1966). In that paper, Donnellan was arguing against the classic positions on reference assumed up to that point by Russel and Strawson by conjecturing a distinction between two uses of definite descriptions, a referential and an attributive one:

To illustrate this distinction, in the case of a single sentence,consider the sentence, "Smith's murderer is insane." Suppose first that we come upon poor Smith foully murdered. From the brutal manner of the killing and the fact that Smith was the most lovable person in the world, we might exclaim, "Smith's murderer is insane." I will assume, to make it a simpler case, that in a quite ordinary sense we do not know who murdered Smith (though this is not in the end essential to the case). This, I shall say, is an attributive use of the definite description.

The contrast with such a use of the sentence is one of those situations in which we expect and intend our audience to realize whom we have in mind when we speak of Smith's murderer and, most importantly, to know that it is this person about whom we are going to say something. For example, suppose that Jones has been charged with Smith's murder and has been placed on trial. Imagine that there is a discussion of Jones's odd behavior at his trial. We might sum up our impression of his behavior by saying, "Smith's murderer is insane." If someone asks to whom we are referring, by using this description, the answer here is "Jones." This, I shall say, is a referential use of the definite description (Donnellan, 1966, pp. 285-286)

This distinction, as well as the two scenarios, were afterwards (again) fiercely discussed by Kripke, Searle and Bach. I have posted a few times on this problem and its tradition, see here.)

John & Smith & Brown & cars

Let us suppose that Smith has strong evidence for the following proposition:

(f) Jones owns a Ford.

Smith's evidence might be that Jones has at all times in the past within Smith's memory owned a car, and always a Ford, and that Jones has just offered Smith a ride while driving a Ford. Let us imagine, now, that Smith has another friend, Brown, of whose whereabouts he is totally ignorant. Smith selects three place-names quite at random, and constructs the following three propositions:

(g) Either Jones owns a Ford, or Brown is in Boston;

(h) Either Jones owns a Ford, or Brown is in Barcelona;

(i) Either Jones owns a Ford, or Brown is in Brest-Litovsk.

Each of these propositions is entailed by (f). Imagine that Smith realizes the entailment of each of these propositions he has constructed by (f), and proceeds to accept (g), (h), and (i) on the basis of (f). Smith has correctly inferred (g), (h), and (i) from a proposition for which he has strong evidence. Smith is therefore completely justified in believing each of these three propositions. Smith, of course, has no idea where Brown is.

But imagine now that two further conditions hold. First, Jones does not own a Ford, but is at present driving a rented car. And secondly, by the sheerest coincidence, and entirely unknown to Smith, the place mentioned in proposition (h) happens really to be the place where Brown is. If these two conditions hold then Smith does not know that (h) is true, even though (i) (h) is true, (ii) Smith does believe that (h) is true, and (iii) Smith is justified in believing that (h) is true

This one is a bit simpler since it does not involve any definite descriptions. However, the objections to (ii) do apply: it is not clear in what sense S is justified in believing (h) if Jones does not own a Ford. Some early responses attempted to save JTB by rejecting (ii) – thus, by adding the condition that the belief not be inferred from false premises. An example of this is given by Wikipedia:

After arranging to meet with Mark for help with homework, Luke arrives at the appointed time and place. Walking into Mark's office Luke clearly sees Mark at his desk; Luke immediately forms the belief 'Mark is in the room. He can help me with my logic homework'. Luke is justified in his belief; he clearly sees Mark at his desk. In fact, it's not Mark that Luke saw; it was a marvelous hologram, perfect in every respect, giving the appearance of Mark diligently grading papers at his desk. Nevertheless, Mark is in the room; he is crouched under his desk reading Frege. Luke's belief that Mark is in the room is true (he is in the room, under his desk) and justified (Mark's hologram is giving the appearance of Mark hard at work).

A further objection might be advanced, this time as to what Gettier means by having justification for something. One might interpret the phrase as "there being something out there that can justify one's belief". One might choose to say Jones has justification for believing that man landed on the moon when Jones believes that unjustifiably, i.e. without considering the justificatory evidence. But one might also interpret it as "there being something out there that can justify one's belief and that person using it as such". In this case, we could not say the same about the situation with Jones' belief of man landing on the moon; there is a justification out there, but Jones does not have it. 

Gettier did not propose any solution to this problem, which is how he managed to keep his paper so short.

PS: In order for the discussion not to be jumbled one might formulate the following question: How can two discussants agree on a standpoint but disagree on the arguments which must be taken as a good defence of that standpoint? At first glance, it is simple: they just don’t agree on the arguments but they (happen to) agree on the conclusion. But is this even possible? They might also disagree on the standpoint “P because Q”, or something similar.  

Alvin Plantinga (1992). Warrant: The Current Debate. Oxford University Press. pp. 6–7