This Week’s Special: Edmund Gettier, “Is Justified True Belief Knowledge?”

By Daniel A. Kaufman

On tap this week is one of the most widely read and influential essays in epistemology, written since the Second World War, Edmund Gettier’s “Is Justified True Belief Knowledge?”

In this remarkably short piece, Gettier succeeded in casting doubt on what had been one of the most widely accepted ideas in philosophy – that to know something is to have a belief that one can justify and which is true – a view that goes at least as far back as Plato’s Theaetetus and which has been called the “Tripartite Theory of Knowledge” (TTK).

Gettier’s case against TTK is made via counterexamples.  Gettier presents us with cases, in which a person has a belief, P, for which he has justification and which is true, but which he nonetheless, does not know.  His cases are ingenious and rely on just two assumptions, both of which seem uncontroversial: (a) one can be justified in believing something that turns out to be false; (b) justification is transitive, through valid inferences, such that if S is justified in believing P and Q follows logically from P, then S is justified in believing Q.

Gettier presents two cases which  are needlessly complicated.  As a result, others have come up with “Gettier-style” cases that are simpler and yet, serve as counterexamples in precisely the same way as the originals.   You can easily check out the original Gettier cases in the article, linked above, but here are two simpler, Gettier-style cases that make the same point.

(I)  Imagine that we are sitting together in a sports bar, watching the Wimbledon final between John McEnroe and Bjorn Borg (my age is showing), and suppose that we see John McEnroe win the match.  As a result, we believe that John McEnroe has won Wimbledon and certainly are justified in that belief (if asked, we will say that we just watched him win, on TV).   Also imagine, however, that this year, Wimbledon’s TV feed has gone down and that unbeknownst to us, we have been watching a rerun of last year’s match.  Suppose also that John McEnroe has won this year’s Wimbledon as well.  Under such circumstances it would seem that even though we have a true, justified belief that John McEnroe has won Wimbledon, it would be very strange to describe us as  “knowing” it.

(II)  Imagine that we are driving through the countryside and observe a lone sheep on a distant hilltop.  As a result, we both believe that there is a sheep on the hilltop.  But suppose that, in fact, what we have seen is not a real sheep, but rather, a mock-up of a sheep.  Suppose, in addition, that there is another sheep on the hill, behind it, that we cannot see.  Once again, we have a belief that we are justified in holding and which is true, but it would be awfully odd to say that we know there is a sheep on the hilltop.

These cases – as well as Gettier’s originals – reflect two very common and well-understood facts about us and our “epistemic condition”: that we may stumble upon the truth entirely by accident or even by way of misleading information; and that what may seem, by every measure, to be the best reason in the world for believing something, may in fact turn out to be no good reason at all.


As you might have expected, there was an explosion of activity in the epistemological community, in the wake of Gettier’s article.  One prominent strategy in dealing with the Gettier cases is to add a defeasibility condition:  S knows P, if S believes P, P is true, S is justified in believing P, and there are no defeating statements (i.e. no statements that would defeat S’s justification). (1)  This would render Gettier style cases harmless for TTK, for in each case, there is some statement that – had the person known it at the time – would have defeated the justification for the relevant belief. The trouble with this is that it turns out that it is not as easy as one might think to define what counts as a defeating statement and furthermore, one can never be sure whether some further information might not come along that would defeat the defeater and render the original belief justified after all. (2) One realizes, in taking into account such considerations, that no belief could ever really be justified, on the defeasibility view, because no one could ever know whether there might be some potentially defeating statement of which one is not yet aware.

Another prominent strategy is to build a causal condition into our definition of knowledge, in the manner suggested by Alvin Goldman. (3)  What this does is require that for S to know P, his belief that P must — in some “appropriate” sense — be causally connected to P.  (p. 369)  This proposal also avoids the Gettier counterexamples, because in each Gettier-style case, having the relevant true belief is lucky, rather than the result of being causally connected to the truth-maker.  It’s not the sheep that makes me believe there is a sheep on the hill, but rather, a mock-up. That there is an actual sheep is sheer luck.  It’s not McEnroe’s win this year that makes me believe that he won Wimbledon, but rather, a rerun of last year’s match, which – again, luckily — he also won.

The one downside – if it is a downside – to Goldman’s response is that it abandons a long and widely held view of justification: namely, that one’s justification for believing P ought to be some reason or reasoning that one can explain oneself.  That is, justifications should consist of reasons in the believer’s head, so to speak.  This raises a much larger issue regarding the very nature of justification itself, one that has become a major topic of epistemological investigation in its own right, under the name, “The Internalism/ Externalism” debate.


1. Keith Lehrer and Thomas Paxson, Jr., “Knowledge: Undefeated Justified True Belief,”The Journal of Philosophy, Vol. 66, No. 8 (Apr. 24, 1969), pp. 225-237.

2. This is the idea behind the “Tom Grabit” case, in Lehrer and Paxson (1969).

3. Alvin I. Goldman, “A Causal Theory of Knowing,” The Journal of Philosophy, Vol. 64, No. 12 (Jun 22, 1967), pp. 357-372.

43 thoughts on “This Week’s Special: Edmund Gettier, “Is Justified True Belief Knowledge?”

Add yours

  1. Frankly, this is one of the clearest, and most brief, of explications on this topic that I’ve encountered–granted my exposure to the scholarship is quite limited. I have problems quite naturally, I think, with some of the terminology and the question of substitutability with regard to “justification,” such as supposition and certainty, about which I think some further unpacking might be helpful.

    Take your example of the faux-sheep on the which two observers agree on the same conclusion or belief regarding what they see. (Presumably, they mutually agree on what a sheep is. We certainly don’t won’t to complicate matters by introducing the subject of whether a simulacrum is an acceptable substitute.) Perhaps, they hear a “Bah” from the “real” sheep they can’t actually see. This might add further credence to their supposition, but does it suffice or justify a true belief in what they see?

    This in turn raises the question whether the term “true belief,” aside from common logical constraints and constructions, is rather a conundrum in many cases. But I suppose this is Gettier’s point: When is one justified in equating JTB with what is taken to be certainty or knowledge?

    I share your concerns with the “defeatist” argument when you note, “The trouble with this is that it turns out that it is not as easy as one might think to define what counts as a defeating statement and furthermore, one can never be sure whether some further information might not come along that would defeat the defeater and render the original belief justified after all.”

    But I feel some further explication on Goldstein’s argument is needed. For certainly, he would not contend that the hallucinations of a schizophrenic would qualify as “justifications . . . in the believer’s head.”

    I suspect many find this topic as a pointless philosophic exercise, but I find it fascinating and thought-provoking.

    Thank you.

  2. Maybe that is just what is meant with one of the two responses cited, but I have never understood the problem. In my eyes the person in question does not really have a justification for their belief because what they saw wasn’t what they thought they saw. It is irrelevant that they cannot know that they don’t have the justification; when discussing knowledge, there is no way around taking the bird’s eye view.

  3. I am going to have to reread Theaetetus, my recollection is that Plato cast a similar kind of doubt himself. On the other hand it has been ages since I read it.

  4. In this remarkably short piece, Gettier succeeded in casting doubt on what had been one of the most widely accepted ideas in philosophy – that to know something is to have a belief that one can justify and which is true – a view that goes at least as far back as Plato’s Theaetetus and which has been called the “Tripartite Theory of Knowledge” (TTK).

    But not before Plato himself cast doubt on it:

    And it is utterly silly, when we are looking for a definition of knowledge, to say that it is right opinion with knowledge, whether of difference or of anything else whatsoever. So neither perception, Theaetetus, nor true opinion, nor reason or explanation combined with true opinion could be knowledge.

    Apparently not.

    Are we then, my friend, still pregnant and in travail with knowledge, or have we brought forth everything?

    Yes, we have, and, by Zeus, Socrates, with your help I have already said more than there was in me.

    Then does our art of midwifery declare to us that all the offspring that have been born are mere wind-eggs and not worth rearing?

    It does, decidedly.

  5. Alvin Goldman (facebook page)
    April 17, 2015 ·

    Gettier walks up to the counter. Before he can order, the Barrista confuses him for a regular and chirps “I know what you want.” By coincidence, Gettier ends up with exactly the drink he desired.

  6. Oops, “Goldstein”? Just a follow-up note upon re-reading the section on *Goldman’s* argument. I see I misread your final paragraph. You are indicating that his argument “abandons a long and widely held view of justification . . . [that it] should consist of reasons ‘in the believer’s head’ . . . .”

  7. AlexSL: If justifications have to be infallible, then there can’t be any justifications. This, however, is at odds with our actual practices, and its philosophy’s job to give rational reconstructions of our actual practices, not invented or fictional ones.

  8. This issue came up at the old Scientia Salon more than a year ago:

    The two comments I made on that article I then posted on my own blog:

    I titled that posting “Beginnings of pragmatism,” because I think a good case can be made that Pragmatism develops as a response to the problems implicit in adopting certainty as the absolute standard of knowledge we can rely on usefully, especially in the sciences. We can – and I suggest mostly do – rely on justified belief, and treat truth as a contingency. We can also reconceive knowledge by back-tracking knowledge claims to their source *experiences* which will include our intuitions, our bodily responses, our social expectations, the wisdom received from elders or from books – etc., etc. This suggests that “knowledge” is simply a generic term for a set of such experiences we rely on to make judgments in speech or in action. (this does not deny that there are certainties – I’m not doubting “1+1=2” here; but that the knowledge we acquire and live through is not reducible to such certainties.

    This leads to some interesting, if problematic, implications. The principle of these is that there are forms of knowledge not reducible to logically determinable claims – indeed, some that never get articulated in language (except perhaps in poetry); and contrary to current insistent demands from some scientists, some philosophers, some public intellectuals – there are other ways of knowing than those we find in the sciences (and it is now widely admitted that there may not be even one way of knowing – one methodology – in the sciences).

    Again at my blog, following up on the implications here, I wrote two discussions:

    The Gettier problem is a puzzle those in the Analytic tradition will continue to worry about, because not all the pieces are on the table – indeed, the tradition has largely banned them from the table. Once we begin allowing those pieces their proper places, while we won’t be rid of all puzzles, Gettier may be one we can feel safe in setting aside.

  9. So yes, maybe I really don’t understand the problem. But I see no fundamental difference between a typical Gettier case and, say, some very confused person saying “I know Paris is the capital of France because Elizabeth II is queen of England”. That person just used a non-sequitur. They didn’t know that, but they still did. They should have checked if their reasoning made sense. Gettier should at least have walked up to the “sheep” and checked if it really was a sheep, and checked if he was really watching this year’s match.

    That being said, maybe a case can be constructed where our intuition tells us that nobody could be expected to check if what they saw was correct. They would be rather contrived I guess. But if that is the case, then maybe there simply is no knowledge in the specifically philosophical, deductive sense to be had about empirical matters.

  10. DK. “we may stumble upon *the truth* entirely by accident or even by way of misleading information; and that what may seem, by every measure, to be the best reason in the world for believing something, may in fact turn out to be no good reason at all.”

    One problem: what is “*the truth*”? What is “the truth” of “a sheep on hill”?

    Whether our mental activity is thinking, believing or knowing are nice graduations of the meaning of fuzzy words, -Philosophy’s and Humpy-Dumpty’s happy hunting ground. One man’s lamb is another man’s mutton and both are meat. How do I know this is a chair under me? It is 99.99..% certain for me, IFF I have sight and/or feeling and I can see it and/or touch it and I am awake and can sit on it. Its existence, unlike its comfort, for me is not a matter of opinion. I can also see a chair on the other side of the room (though its existence is now very slightly less certain than that of the one in which I am sitting), but for a totally blind person the existence of a chair out of reach is no longer perceptible, though it may be known to exist from in his memory of past experience.

    Truth is never absolute. All human data, information, knowledge finally depends on, and its probability is as reliable as, our accumulated human sensory perception of phenomena, (those outside our perception we have to infer or translate into observable experience), and then only until falsified by a new perception.

  11. For those interested, Mike LaBossiere on the blog “Talking Philosophy” has a related discussion without going into Gettier. The link is here:

    Encountering this article today seems rather serendipitous for me since I’ve been running simulations of certain strategies in the game of casino craps. The objective is to design a strategy not to win, since the rules of the game itself ensure a negative outcome if pursued long term, but to lose as little as possible while “winning” compensations such as free meals or beverages or a free room and other intangibles such as being entertained by the game itself and the other players.

    It’s an interesting piece that touches on the probabilities and objectives and ancillary considerations that factor into and shape JTB. Unfortunately, it also brings to mind Pascal’s Wager which I no longer find compelling.

  12. Hi Mogguy,

    “Truth is never absolute.”

    If there are no absolutely true propositions, then the proposition that “truth is never absolute” is also not absolutely true.

  13. Hi DanK, yeah I went through this in undergraduate epistemology, along with an extensive review of justified knowledge via Bonjour. As always you seem able to condense and clarify philosophical positions and arguments better than I ever could.

    I sort of cut the Gordian knot on all these epistemological concerns.

    Defining knowledge is easy: a sincerely held belief that is true. In the two cases presented, knowledge exists. So what if the source was luck? “Luck” is merely a qualifier on the state of knowledge… that the source was happenstance and so unreliable.*

    Establishing criteria when one can claim knowledge (prior to extensive checks between belief and “truth”) is the stickler. Requiring justification is often useful but then we are forced to admit that we will never avoid being fooled 100% of the time.

    Again, so what? Recognition of fallibility and luck in the realm of knowledge is critical and not some sort of setback… except for those who believe omniscience is possible.

    *Note that in each case if asked how they know, the person would point to the video watched or the sheep on the hill. If asked is that the victory (on the screen) or is that the sheep (on the hill) they would say yes… and then be very wrong. So while they know which player won and that there is a sheep on the hill, they do not know how the victory occurred or what/where the sheep is. This is the problem of unreliable sources of knowledge.

  14. In fact I think that the objection that Plato raised to TTK in Theaetetus is more severe than Gettier’s, in that it applies also to any attempt to fix the definition.

    Goldman’s strategy may get round Gettier’s objections but it still falls foul of Plato’s

    I am also a little puzzled that Gettier says that Plato ‘seems to consider’ this definition for knowledge in Theaetetus, Plato’s rejection of it could not be more clear.

  15. “Never say never, never say always”. This little truism captures the recognition in the medical world that one can ‘never’ be certain, except in a pragmatic sense – one must decide after obtaining as much information as seems reasonable and proper. When dealing with human beings pragmatic certainty is frequently imperfect. The most spectacular example I encountered was a case of a distinct phantom tennis ball sized ‘mass’ adjacent to a kidney. After appropriate pre-operative evaluation the ‘tumor’ and kidney were excised, only to reveal virtually nothing on careful examination of the specimen. Everything removed appeared almost normal. The computer algorithm of the CT scanner apparently had produced a completely non-existent artifact on the patient’s imaging studies.

    The justified belief of physicians regarding a serious matter turned out to be completely erroneous due to the presence of a spurious structure on images of the patient. Unfortunately, this is a problem that doctors and patients have to deal with everyday.

    The problem of spurious or misleading observations, or misinterpretations of such, has been well recognized in science. Descartes drew formal attention to it in the West, but this problem has probably been recognized for millennia. Theologians, for obvious reasons, do not like to consider the implications of fundamental error and uncertainty. Modern philosophers seem to suggest that since they discover knowledge through argument and ‘higher-order philosophical theory’, they also could therefore be immune to the Gettier problem.

  16. It is a little difficult to see how anyone could read into those words that Plato saw even a remote hope that definition could be rescued. Certainly the SEP article fails to specify how this could be done. It is not as though those words express any uncertainty.

  17. Hi Dantip,
    Thanks for pointing out my howler.
    Would you accept “We can never know if what we know is absolute truth.”?
    Or just delete it. It was unnecessary anyway.

  18. But what fascinates me is the idea that there might be a fact of the matter about my belief being or not being justified and no one know about it.

    This could not be a fact about the physical environment, because what does it even mean to say that such and such group of atoms justifies such and such other group of atoms?

    On the other hand it cannot be something mental because, by hypothesis, no one knows about it.

    So what sort of a fact would it be?

  19. While I certainly agree with the above logic of Edmund Gettier, it does seem to me that the ideas of a much earlier philosopher not only addressed this, but far more. Who? René Descartes. (Wherever I get Descartes wrong below, I’d be honored to accept the credit/blame for the following position. I don’t actually know/care if it remains historically accurate, but nevertheless consider the following logic to be sound.)

    “I think, therefore I am” suggests to me that thought is all that one can possibly “know,” since EVERYTHING except for thought itself could indeed be false. Thus your thoughts can never be known to be true, but only that you are indeed thinking (that is if you are indeed thinking). Furthermore I interpret “thought” as the processing element of the conscious mind, or something which effectively exists AS me. Without it, such as during perfect sedation, “I” no longer exist. This position maintains that my body isn’t me, but rather the conscious processing which I presume my body to do.

    Instead of “knowing things” (other than that thought exists if/when it does), I believe that we merely “presume” things. I could go into the single method by which we make our presumptions, since I do have a basic idea in this regard. For the moment however, the above observation should suffice.

  20. Eric: Descartes and Gettier are not asking the same question. Descartes question concerns the justification of our beliefs. On what basis do we know such-and-such and is it a good basis? Gettier’s question is what counts as knowledge? Given that we believe such-and-such, have a good basis for it, and given that it’s true, do we know it?

  21. Labnut: If your question is directed towards me, the answer is “probably very little or none.” But it does effect the way that we conceive of the inquiries in which we engage. It also goes to the differences between concepts that we use on a regular basis — “belief”, “knowledge,” “reasons,” etc..

  22. Let me add that the above is one of a series of essays by Jennifer Nagel on the Brains Blog. Happy reading!

  23. Anyone who supported the TTK could simply reply to Gettier that he had not found any counter examples because he is only described cases where people had something that seemed like a justification for their belief, but did not in fact have that justification.

  24. Also, this does rather seem to be a rather minor issue in the general problem of knowledge. I have know way of deriving even a rough probability that I have existed for more than a second or that the other people I interact with are conscious individuals rather than being like figures in a dream. Even if I were to watch the sweep hand of a clock as it rotates a full minute and say to myself, “there, I have existed for at least a minute” I don’t know that I haven’t just started to exist a second ago with the memory of watching that sweep hand ready made.

    If my perceptions of the world around me could be spurious then I would have no knowledge of what the actual world was like, what kind of rules it worked by and what kind of beings might be there and what motivations they would have to do things, for example to simulate a few moments of my consciousness.

    There does not seem to be any way that I could know anything. Not even having a definition of “know” is really not a large part of the problem.

    And yet, it seems to me that I know quite a lot.

  25. Dan K – it looks as if you may know Brendan Fitelson. Very nice and of course brilliant guy with whom I had a couple of conversations when bumptuously crashing some Rutgers-Princeton-Penn epistemology events. In the last one I was saying I thought there ought to be some real philosophy (not sociology) to be done on the subject of a massive breakdown of such common sense or steadiness as we used to have about what sources of information to take seriously, and that the field tended towards papers on what to me seem like precious distinctions; often variations of the Gettier case — with the exception of a few like Goldman (funny you use a 49 year old paper of his) and Philip Kitcher who feel compelled to think about such things.

  26. DanK. “..we have a belief that we are justified in holding and which is true, but it would be awfully odd to say that we know there is a sheep on the hilltop.”

    You say it is indeed true that there is a sheep on the hill but this is only so because you have added this unprovable, artificial condition, just as Gettier does every time. In real life who is to know, what proof is there? Other than we see it, hear it and/or touch it. There is no way of “knowing” that we are not a figment of someone else’s dream, a brain-in-a-vat or a computer simulation, etc.

    Lastly, what is this subtle difference between believing and knowing? Is there anything that can be added to a justified belief to make it a piece of knowledge? Is it not just the case that some beliefs/knowledge may be reasonably assumed to be truer than others? Eg. The differences between today, tomorrow and next year, life here on Earth and life not on Earth.

    I reason that life after death is highly unlikely.
    I believe that all life has evolved from ancestors.
    I know that tomorrow will be Friday and that I shall be one day older.

  27. Daniel, in practice I consider the difference between Descartes and Gettier to concern degree more than kind, with Descartes taking the extremity. Sure if I am given that something is true then it can’t be false by definition, even if my belief in it occurs for a mistaken reason. In that sense it may be said that I don’t “know” something which is nevertheless true. But even worse is that there are no true givens in existence except for “I think,” and thus we must presume our supposed givens to be true, such as the number of sheep on a hill, or that there is any physical existence whatsoever. Thus it should all go back to Descartes in the end — a difference in degree rather than kind.

    Given our lack of ultimate givens, I’m not sure that Descartes or Gettier address the process by which make our presumptions. The following is my own associated epistemology: We take what we think we know (evidence), and use this to assess ideas that we’re not so sure about (theory). As a give theory continues to stay consistent with what we think we know, it does tend to become more accepted. Even without language, I think, all conscious figuring occurs in this way. (I’m also aware however, that this presupposes the existence of something other than me.)

  28. Hal: What’s funny about the Goldman paper I chose? It — plus the Lehrer and Paxson piece — is one of the most basic responses one reads, when first learning the subject. These “Specials” are intended for people with knowledge neither of the subject nor the key literature.

    As for Brendon, no, I don’t think I know him.

  29. moguy: As I explained to Eric, the issue here is not skepticism, which consists of challenges to the justifications we give for our beliefs. The issue here is how knowledge is to be defined and whether, belief+justification (whatever it consists of) + truth is sufficient.

  30. Hal: What’s funny about the Goldman paper I chose? It — plus the Lehrer and Paxson piece — is one of the most basic responses one reads, when first learning the subject.

    Dan. I made no comment on the Lehrer and Paxson piece, but that gives me a hint what you’re reacting to — did you think I was deprecating the age of the papers? No, it’s just that I posted Goldman’s Gettier joke before even reading down to where you mention him, and then his 49 years ago self crops up. That’s a long time; even I couldn’t have a 49 year old paper, even if I was a philosophy prodigy as an undergraduate.

    Re Fitelson, I jumped to the conclusion because at least twice you’ve referenced papers on his site (in this case I guess he just has loads of convenient material.

  31. Dan. I second others’ comments. Your examples and presentation generally are better than Gettier’s and make the whole thing seem less like a clever riddle.

    I can’t fathom the state of mind of thinking knowledge = justified true belief. I want to ask “How justified is justified?”, and think it’s pretty obvious that someone might have a “justification” for a belief but the justification is wrong, and whether or not the belief happens to be true should be irrelevant.

    So, per Lehrer and Paxson, one could give a “defeater” like “but what lead you to think there’s a sheep on the hill was a fake sheep”, and and one would have to conclude “No, I didn’t really know there was a sheep on the hill. One has no basis to conclude there is no sheep on the hill, if part of the hill was not visible.

    Goldman’s point is if the actual fact of a sheep on the hill didn’t cause the belief, then the belief, while true by coincidence, isn’t knowledge.

    The notion that anyone though, prior to Goldman, and might still think if they reject his argument, that we are justified or not based purely on what is in our mind seems mind-boggling. I’d want to know the definition of “external” that makes it a problem, or more to the point, excludable. Light rays coming from the sheep to ones retina seem not to raise an objection, but the matter of whether “sheepness” caused you to believe there was a sheep is somehow objectionably external? I get the impression that that sort of pure internalism is doomed for a number of reasons.

    John Hardwig’s “Epistemic Dependence” (J. Philosophy 1985) points out that much “knowledge” generated today can’t be said to be personally known by any individual, if knowledge involves personally having a justificatory argument — that physics results, like that a certain kind of quark exists, or has certain properties are achieved by teams of often 100 scientists, all relying on eachother’s expertise, as well as on certain artifacts or outputs of computers or other machines. That such knowledge cannot be known by one individual is merely an extreme case. The actual things that anyone says they know, even if theoretically simple enough for one person to “know” are generally not know in that sense by the typical person who says he or she knows them. The knowledge came to them via structures and processes involving many different people.

    IMO if there is such a thing as rigorously defined personal knowledge, it plays little role in anyones’s life; it is more of a curiosity that we might be able to show examples of. My strong suspicion is that we’d do better studying processes or systems that we say (with some justification) generate knowledge, and the qualities of such system that make them good or bad at knowledge projection, could be studied with far more hope of useful results than the phenomenon we call “knowledge” looked at directly, and questioned as to whether or not it is “true” knowledge.

  32. Plantinga points out that not only do you need to have reliable ways of acquiring information, one also need to have an environment that is amenable to your particular cognitive faculties (or strategies).
    Once you start having to have knowledge as to whether your current environment is conducive to forming correct beliefs, it sounds like we are entering Rumsfeld territory…

  33. DanK. Actually, the issue here IS skepticism and its challenges. Not simply its challenge to “the justifications we give for”, but because it challenges at the outset any possibility of 100% belief.
    When you see a sheep, or even only an imaginary sheep, is that sight of a sheep not some sort of factual knowledge, that there is some degree of possibility of “a sheep” being where you see it? Is no sensory perception to be accepted as knowledge without requiring such stringent, self-defeating conditions, “justification (whatever it consists of) + truth” (whatever that consists of) which make the concept of knowledge an unattainable chimera, its comprehensibility impossible? It seems hardly surprising to me that this “problem” has rumbled on for over 2 millennia.
    You know you will die. How do you know this? Because others have died. But you don’t know when or how. So, although you can’t get an “ought” from an “is”, more usefully you can get a “probable'” from a “was”.

  34. Daniel I’ve thought a good bit more about this Descartes/Gettier situation. Given that the philosophy community was quite aware of Descartes when Gettier released this influential paper, I’ve no doubt that they’ve used somewhat different definitions from my own. The question is, are the definitions which I use, reasonable?

    In common language I see “belief” as a term which is less justified than “knowledge.” Observe for example that your boss will likely become angry if you always answer his/her questions with what you “believe” rather than “know.” We are indeed paid to function with conviction, and so must “know” what we’ve done, not simply “believe” it! And for the mundane and practical matters that Gettier was surely referencing, I am able to conform — counting sheep on a hill for example, or whether or not I’ve been working on a project for my boss. But when I’m referring to reality itself, as I do both privately as well as in public forums such as this one, I choose not to discuss what I “know,” but rather only what I “believe.” Belief + Justification + Truth ≠ Knowledge, as Gettier implied. So we don’t actually “know” much of anything!

    Just above my last comment, Robin Herbert mentioned that he doesn’t even “know” that he existed a second ago. Quite right! In contexts such as these, apparently he and I remain quite concerned about speaking accurately. I do hope others are able to tolerate us literal thinkers!

  35. Labnut: I don’t see much relation to Quine’s web of belief either. That too is about justification — how beliefs are warranted — which is not what the Gettier cases are about. Their aim is to challenge the view that what knowldge consists of is true, justified, belief.

  36. I’ve never understood arguments like Gettier’s as to what constitutes True Knowledge. The so-called counterexamples are taken as defeating “justified true belief” on what basis? In the original post, “it would be very strange” to call the knowledge in such cases True Knowledge. Why? What is the falsifiability criterion at work here? Nothing at all but our pretheoretical intuitions. Well, if our pretheoretical intuitions are definitive, why bother with a “theory” at all, or attempt a definition? It’s like an absolute monarch who has a parliament, but who retains the right to have them dissolved (or arrested, or executed . . .) if they ever pass a law he doesn’t like.

    Whence the certainty that there is any such thing as True Knowledge that admits of a pure, decisive definition? The whiff of Platonism is thick in epistemology in general.

Leave a Reply

Up ↑

%d bloggers like this: