Norris, Gettier, Euthyphro, Hume and Plato: Is knowledge justified true belief?

[ Section on Gettier revised 1/7/11 ]
[ Mention of Euthyphro dilemma as applied to epistemology revised 2/23/11 ]

When deciding whether knowledge is justified, true belief (Plato), a question arises: Is the truth of a belief 1) external to the knower and true whether or not the belief is recognized ‘by’ the knower as justified by the evidence (as realists would say), or is truth 2) internal to and therefore the evidence-based, best opinion of the knower (as anti-realists would say)?

Skeptics and anti-realists would say that if truth is external and evidence-independent, we have no basis to conclude a statement is true (to believe it)—its truth is beyond any knower.  Skeptics and realists would say that if it is internal, it is a fiction—sometimes a statement we thought was justified turns out to have been mistaken (“argument from error”), and sometimes we are right for the wrong reasons (Gettier problem examples, discussed below), so there is not a ‘necessary’ relationship between truth and justification (evidence)—so skeptics conclude truth cannot be known.

Response Dependence theorists try to answer skeptics and resolve the realism/anti-realism conflict by saying that truth is both external and internal—it is the best opinion of the most qualified knower. But is it the best opinion because they are the most qualified, or are they the most qualified because it is the best opinion? That is the Euthyphro Dilemma of truth, which is actually better worded this way: Are we justified in believing because it is true, or is it true because we are justified in believing? Socrates’ original Euthyphro Dilemma applies only to moral truth and can be rephrased: Is God optimally qualified to give his best opinion on the good, or is God optimally qualified to recognize the good when he sees it? It is a dilemma because if the answer is ‘best opinion’ then good is merely a construct, and if the answer is ‘recognize’ it means (setting epistemology aside for the moment) good is over and above him, when there shouldn’t be anything over and above God. This dilemma is resolved by granting that God ‘is’ the good he recognizes. However, returning to epistemology, skeptics about truth in general, if they grant (perhaps for the sake of argument) that God exists, will still insist that if moral truth is not merely an internal construct, then it is external and beyond any knower—even an omniscient one (an argument against omniscience).

Critical Realists answer skeptics and anti-realists (counting RD theorists) by saying that while a statement is true by correspondence (external to the knower), it is justified by the evidence (evaluated and flexibly reevaluated as needed, internally by the knower), and while it is ‘evidently’ (internally) “true” (externally) that sometimes we find out we are wrong (the skeptic’s “argument from error”), we only ‘know’ this because, in order to find out we are wrong, we must find out some other evidence is right (before we knew it was right, so ‘externally’) about an alternative statement that is true (externally) instead of the statement we were wrong about—so skepticism is self-defeating, relying on realist premises: truth can be known, is external to the knower and is evidence-independent. This is the resolution to the Euthyphro Dilemma of truth. Our belief is justified (in that we ought to believe) by the evidence, true by correspondence.

Like Hume’s is-ought fallacy, Gettier’s problem examples (see link in “Sources” below) show that there is not, nor can there be, a necessary relationship between truth (is) and justification (ought). The examples show that just because a belief is true, does not make it justified, and just because a belief is justified, does not make it true, which, if violated, commits Hume’s is-ought/ought-is fallacy. Hume’s is-ought fallacy is prevented from resulting in [moral] skepticism by requiring that knowledge [of a real ought] is belief that is justified by evidence (not by correspondence), and true by correspondence (not by justification/evidence). Although Gettier claimed to undermine the justified-true-belief definition of knowledge, he really only showed that when our belief is not both justified by evidence and true by correspondence, we can be 1) right for the wrong (or no) reasons (where Gettier went wrong was in allowing wrong reasons to count as right reasons, expanded upon here), or 2) wrong despite having right reasons. In the first case, our belief is true, but it is not justified. In the second case, our belief is justified, but it is not true. So, knowledge is when belief is both justified and true—when we are right for all the right reasons. If later we find out we were wrong [that our belief did not correspond, or that we were right for the wrong, or no, reasons], then we were not “knowing” in the first place. We only thought we were. But, now we ‘are’ knowing. We are knowing why we were wrong!

Only the critical realists can answer the skeptics by properly accounting for the progress in scientific knowledge, allowing for truth that is external (and so discoverable, rather than constructed) to the evaluative and reevaluative critical knower. “For to seriously doubt that Boyle was justified (as against Hobbes) when he affirmed the possibility of a vacuum is to undercut the grounds for rational belief in a whole vast range of subsequent developments and causal-explanatory theories,” (Norris, p. 180). Of course this is just one example of progress, among countless others. Plato is still right, despite all these years of progress, that knowledge is belief that is true by correspondence and justified by evidence.


Christopher Norris’ “Epistemology”
Edmund Gettier’s “Is justified true belief knowledge?”
Socrates’ “Dialogue with Euthyphro”
David Hume’s “A Treatise of Human Nature”
Plato’s “Theaetetus”

This entry was posted in Divine Essentialism, Euthyphro Dilemma, Gettier Problem, Is-Ought Fallacy, Justified True Belief, Norris' Epistemology, Reviews and Interviews. Bookmark the permalink.

3 Responses to Norris, Gettier, Euthyphro, Hume and Plato: Is knowledge justified true belief?

  1. Hi Maryann! Thought provoking as usual. A few comments:

    1. Haven't read the work by Plato you reference, but my understanding is that Plato is more of a rationalist than a correspondence-truth theorist. (Of course, I'm committing the fallacy of trying to shoehorn Plato into modern philosophical categories.) In the Republic he outlines a conception of truth and reality that looks very different from what you have above.

    2. From a pragmatic perspective – what exactly would “truth external to the knower and true whether or not it is recognized ‘by’ the knower” look like? Would it be any different from our typical notions of truth? I'm unsure about this notion of “truth outside us” because I cannot think of any way in which we could tell whether or not a particular truth was external to us – our very knowing it or being able to evaluate it means it is not outside of us.

    Perhaps a better way to go about it would be a concept of “truth that makes sense given our experience.” This truth is tentative, as we are always discovering more. This is the theory of truth outlined by thinkers like William James.

    3. Interesting how you respond to typical skeptical positions. Skepticism itself is a pseudo-problem, one I don't spend my time on anymore. If you're curious I can explain.

    4. I like your Euthyphro dilemma of truth. I'm not sure how well you resolve it. Given the complex and specialized nature of much knowledge today (not just in the sciences even), we reply on “qualified opinion” as our criterion of truth all the time. Example: global warming. Under what circumstances can we do this? And when is it not right to do so?

  2. Hi Jonathan :) The idea of “justified, true belief” came from Plato's Theatetus, actually. And see this:

    Truth we don't know yet, doesn't look like anything, yet :) It only looks like something 'after' we know it. The point is, it is true before we know it, not 'because' we know it. We don't make it true–that would be a contradiction. What we (or our experience) make(s), is fiction. An idea works (we arrive at it through experience) 'because' it is true (however, it's working, our experiencing it, does not 'necessitate' its truth), rather than being true because we have experienced that it works (sounded redundant). And even if a way of looking at things 'is' 'typical' doesn't make it true. Call qualified opinion just that, and not knowledge/truth.

  3. P.S. I'm revising the part on Gettier…bleh :)

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