Sunday, 6 May 2012

What is knowledge?

If knowledge isn't Justified True Belief, then what the hell is it?

Philosophers like to analyze concepts; that is, to take a concept and give conditions necessary and sufficient for that concept. For example, an analysis of ‘talking bullshit’ might go something like:

  • A person p is talking bullshit if and only if a) p says that a statement is true or false, and b) p does not know whether that statement is actually true or false, and c) p is indifferent to the truth or falsity of that statement. (Or something similar).

We can draw from this analysis that all it is to talk bullshit is to fulfill conditions a, b and c in the analysis. That is just what ‘to talk bullshit’ means in everyday language.

More interestingly, philosophers like to discuss knowledge, which has a few more strings attached. Ever since Plato, the widely-accepted analysis of knowledge in philosophy was the following:

  • A person p knows a proposition x if and only if a) p believes x, and b) p is justified in believing x, and c) x is true.

That, it was thought, is all it means to know something. If I know that I had breakfast this morning, all that means is that I have a ‘justified true belief’ that I had breakfast this morning. All it is to know that I had breakfast this morning is to fulfill conditions a, b and c in the above analysis, concerning breakfast.

However, Edmund Gettier, a little known American philosopher, wrote a 3 page article in which he demolished this long-held analysis of knowledge with such force that the ‘justified true belief’ model was instantly discredited by the philosophical community. He came up with an example to show that there are cases where a person could have a justified true belief, yet still they would not have knowledge in those cases:

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

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

Smith's evidence for (a) 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 (a) entails:
b. The man who will get the job has ten coins in his pocket.

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

(Gettier, 'Is Justified True Belief Knowledge?'. Analysis 23 (1963), 121-123.)

However, as it turns out, Smith gets the job; the president has a sudden change of heart and decides to hire him instead of Jones. Furthermore, Smith too has ten coins in his pocket, which he had previously deposited there but had forgotten about.
What then, shall we say about this case? Well, Smith had a justified true belief that ‘the man who will get the job has ten coins in his pocket.’ It was true, as it turned out. Smith was justified in his belief as well, since he had it on good authority that a man with ten coins in his pocket would get the job (Jones). However, do we really want to say that Smith knew that ‘the man who will get the job has ten coins in his pocket?’. No, because his ‘knowledge’ turned out to be accidental. Therefore, knowledge is not justified true belief after all. Knowledge cannot be accidental - there must be something added to the analysis to rule out such accidental cases. As of 2012, philosophers are still looking for the answer.
Rarely in philosophy are there any really significant developments or widespread changes in thought. However in this case, it is undeniable that Gettier instigated one. Having published his paper in 1963, he has proceeded to sit back looking justifiably smug ever since, and as such has never published anything else, though he retains his status as Professor of Philosophy at the University of Massachusetts. Papers published: 1. Philosophical revolutions set in place: 1. That’s not a bad success rate.


  1. Layman here, it seems to me that believing a statement of another (the president of the company) to be a concrete fact is the weak point here. Of course people can change their mind. I can't say "I know he will get the job b/c they told me so". Obviously the entire company could blow up tonight. So this doesn't really do anything for me without further explanation.

    1. What then would, for you, be an adequate justification for believing that this person would get the job?

      Actually, this raises an interesting point, Tom, on the point of justification.

      You (or the author of that paper, rather) say Smith had a justified true belief, because at the time of the conception of his belief, he had intelligence to suggest his belief was true. But I would suggest that perhaps this belief was not justified at all - the belief that the person ultimately hired would have ten coins in his pocket turned out to be true, but was based on a faulty assumption - the assumption that Jones would get the job.

      Surely for a belief to be in itself justified, any assumptions made in the justification of that belief must be true?

    2. Two really good points. It's right to press on the notion of justification. I think it's fair to say that Smith had good evidence for the belief - he had it on authority. Ok, so maybe this is too weak, but you can always tweak the scenario enough so that there is adequate justification. Suppose that everybody in the company told Smith that he wouldn't get the job, and then all changed their minds. Surely Smith's belief would be evidenced.

      This does assume, as Esther points out, that justification is independent of truth. That is, it is possible to be justified in believing something false. But surely, this is correct. We might be wrong that the Sun will rise tomorrow (it is possible that it will not, due to sudden irregularities in the laws of nature), but we have good inductive evidence to believe that it will. Even if the sun did not rise tomorrow, we would be justified in believing that it will.

      In this way, building truth into the nature of justification will yield that almost all our beliefs are unjustified. This is skepticism, and we want to avoid this.

    3. Smith's belief is:

      Jones will get the job. Jones has 10 coins in his pocket. Thus the person who gets the job will have 10 coins in his pocket, *given* Jones is that person. Smith's justification for the person who gets the job having 10 coins *is that Jones will get the job and he has 10 coins".

      The "truth" is that Smith gets the job, and has 10 coins in his pocket. But Smith's belief was that the person who got the job would be *Jones*, *and* that person would have 10 coins in his pocket. So upon finding out that Jones *didn't* get the job, Smith's justification for believing the person who gets the job will have 10 coins is *retrospectively unreliable*.



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