Wednesday, January 09, 2008

Defining knowledge: Justified true belief?

The canonical definitions of "knowledge" in philosophy are variants of "justified true belief". At some point we will have something philosophical to say about the justification of knowledge. However, as someone who has come to philosophy from studying science, I have to say that this definition as a definition stinks on ice.

Some time ago, I read Einstein's own explanation of relativity. In the first paragraph, he states that length is what we measure with a ruler, and time is what we measure with a clock. I instantly realized that when we couple those definitions with the observation that the speed of light — our ultimate ruler and clock — is constant for all observers, you get Special Relativity*; the rest is arithmetic. And Einstein didn't even do the arithmetic; Lorentz and Fitzgerald had already taken care of that detail. Einstein's contribution to physics was fundamentally philosophical.

*Special relativity explains a lot of the fun of quantum mechanics as well. We get spin, for instance, because relativistic dynamics introduce a square root, which can be positive or negative.

Definitions in science come in two flavors: The simple, no bullshit operational definitions such as those underlying special relativity, and more complicated definitions such as thermodynamic temperature. However the second flavor of "definition" is theoretical; it exists to explain experiments performed according to the simple operational definitions.

Contrast these scientific definitions with the definition of knowledge as justified true belief.

Right off the bat we have problems: What precisely does "justified" mean anyway? Deduction? Evidence? Perception? Scripture? Prophecy? Worse yet, the word "justified" has its root in "justice", an ethical concept. How did ethics creep into epistemology? We've done nothing but offload our confusion about "knowledge" to our confusion about "justification".

Why the component of "true" in the definition? Adding this component entails that we at least believe that justification can give false results, or, worse yet, inconsistent results. And how do we evaluate the truth of a belief independently of its justification (whatever that it is)? Worse yet, the notion of truth itself is notoriously refractory in philosophy.

What if true beliefs at every level always magically popped into our minds ex nihilo? It doesn't seem likely then that we would still talk about "justification"; extending "justification" to cover this kind of belief would seem to stretch the term to vacuity, and magical true belief formation would seem (so long as we are going to rely on complicated intuitions) to do much the same job that ordinary human beings in this world ask knowledge to do.

Worse yet, as Gettier has shown, not even "justified true belief" captures all our complicated intuitions about knowledge: We can believe something; we can justify (whatever that means) the belief, i.e. we believe it for what seem to be the right reasons (whatever those are); we assume (at the meta-level) the belief is true (whatever that means); and we still don't intuitively feel that we "know" it.

There are other issues which controvert even the notion that knowledge is some kind of belief. Is "knowledge" something available only to a "thinking" being? A self-aware being? Can computers know things? Can cats and dogs? Do books know things? Or... does a computer program or a book "contain" knowledge? These questions are the subject of considerable controversy.

We should be charitable, and consider the case that the philosophical definition of knowledge is a complex theoretical definition to explain some body of fact. But where's the body of fact? Philosophers argue definitions of knowledge against nothing more than their own complex intuitions about what they think knowledge "should" be (there's that ethics language creeping in again). But our complex intuitions — at least those about the physical world — often turn out to be misleading, unreliable or even completely false. And wouldn't we more productively relegate the examination of our intuitions for themselves to the experimental sciences: psychology, neurobiology, etc.?

Even introspectively, I'm completely at a loss in applying the philosophical definition of knowledge to decisively identify even a single one of my own beliefs as knowledge. Is my belief that things fall when I drop them justified? Is it justified in the "right" way? Is it true independently of my justification? Am I right for the wrong (but seemingly right) reasons? How about my belief that there is no God? That the laws of physics are always and everywhere the same?

I'm not arguing that justification and truth are unimportant or unrelated to our conception of knowledge. I'm arguing only that these issues are not definitional. I don't know whether "justified true belief" (Gettier notwithstanding) captures my intuitions about knowledge, but I am sure it doesn't capture my intuition about what constitutes a good definition. And without some body of fact afforded by uncontroversially clear, unambiguous primary definitions, a complex definition has nothing to explain.

I'm not arguing that a good definition should be obviously correct. Einstein's definitions of space and time were a matter of controversy for decades. But, whether or not you agreed with their correctness, there was no controversy at all that they were clear and unambiguous.

8 comments:

  1. So it's more important that a definition be clear than that it be correct? A concocted, precise definition might be useful for some purposes. But it wouldn't be any good if you wanted to explain how the meaning of the English word "knowledge" relates logically to other ordinary-language concepts (which of course it does). And while you may want to ditch ordinary language in favour of something clearer, I don't think you'll get many followers. Which is why there is something to be said for trying to understand English.

    Incidentally, to what could one possibly appeal when trying to figure out how one's own language fits together, besides one's intuitions?

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  2. How can we tell if an unclear definition is correct? Clarity is a necessary (but not sufficient) condition for correctness.

    [I]f you wanted to explain how the meaning of the English word "knowledge" relates logically to other ordinary-language concepts (which of course it does)...

    Then you'd be wanting to do scientific linguistics, not philosophy.

    to what could one possibly appeal when trying to figure out how one's own language fits together, besides one's intuitions?

    I argue against appeal to complex, abstract intuitions. (Unless, of course, one is doing scientific psychology or sociology.)

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  3. Also, I'm not saying that a definition shouldn't be correct: I'm saying it doesn't have to be obviously or intuitively correct.

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  4. Clarity in your sense is not a necessary condition for correctness. To pick a corny example, I don't suppose for a moment that the word "love" can be defined in any very clear fashion, yet there are still reasonable (if provisional) inferences that might be drawn from uses of it, and one can spot idiosyncratic occurrences. So we can talk about how the word connects up with other parts of our language, without ever really making it clear in your (idiosyncratic, proprietary) sense.

    The trouble seems to be that you want to impose an irrelevant standard of adequacy for the elucidation of these concepts. Then, when the proffered definitions fall short, your solution is to suggest talking about something else - something which canpass your tests. But that's just to change the subject. The concept we are interested in is the one we use.

    How do you imagine a scientific linguist's approach would differ from a philosopher's? Come to that, what's a "scientific linguist", as distinct from any other sort?

    And I'd love to hear an operational account of the difference between "complex, abstract intuitions" on the one hand, and "no-bullshit" ones on the other. Is there a threshold, perhaps?

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  5. I've been struggling with this for a while. I can't really get a handle on knowledge with regard to truth or justification. My mind tends to work in the concrete rather than the abstract, so maybe that's why.

    So, what I can get a handle on, or at least I feel I can, is information (e.g. Shannon). Information is merely laid down in the brain, using the physicalist view, in patterns that vary according to person, time, current brain state, etc., acquired through the combination of genetics, development and sensory input and so on.

    Sticking with the physicalist view that consciousness is a manifestation of brain activity that gives an appearance of the 'mind', then the processes of the mind consist of the manipulation and regurgitation of an individual brain's information at any particular time - outwardly, to others, an external representation of the internal information.

    So what we call individual 'knowledge' is nothing more than continuously changing pattern of transformed information. Add into the mix other brains all trying to perform the same task, each with their own internal mix of this 'knowledge', then it's no wonder we struggle to find agreement on what we understand any particular piece of knowledge to be. If there is any 'truth' out there beyond human experience then we're unlikely to acquire or agree on any 'true' interpretation of it.

    Why do we want to search for a truth of any kind? Why must we agree? I don't know what the biological driving forces might be, other than it could be viewed as yet another manifestation of the consequence of housing selfish genes. But it's pretty clear we are motivated to question, to understand, and to agree on 'truths'.

    In this model there is no absolute truth, at least not that we can get at. There is only knowledge as information. What we make of it and how useful it is determines whether or not it is 'justified true belief', though I've never liked that phrase (because I couldn't understand it). And I think this is how such variety in understanding can be explained; how we arrive at such a debatable position about what 'truth' is, what god is, if god exists, what morality is, etc. In some respects this is a utilitarian view, but I don't see anything wrong with that.

    If this interpretation is the case then it also explains in some way the success of science and its methods and why we find them useful: the use of repeatability to establish knowledge as a consistent set of information over time, space and environment; the use of logic to establish what we can conclude or at least what we can use as a working model. Science even goes to great lengths to iron out the noise and the vagaries of human fallibility by using double blind tests and performing statistical analysis on the data to make sure, as much as we can, that the results actually represent useful knowledge/information. In other words science helps us to get as good an agreement on any 'truth' as we can reasonably expect.

    Beyond this view of knowledge I struggle with much of the philosophical contemplation of it. It seems to me that it's quite easy to analyse yourself until you vanish up your own ass, and I feel that that's what some philosophers do when considering truth and knowledge. Maybe it's just my ignorance of some of the finer points.

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  6. Lake:

    Forgive me for replying to your comment out of sequence.

    The trouble seems to be that you want to impose an irrelevant standard of adequacy for the elucidation of these concepts.

    I have to hand it to you, mate: only a philosopher would have the chutzpah to argue straight out that clarity was an irrelevant standard of adequacy.

    ...(idiosyncratic, proprietary)...

    Yet again a philosopher complains that I'm trying to be original. If you're looking for theological reverence for philosophological dogma, you won't find it here.

    I don't suppose for a moment that the word "love" can be defined in any very clear fashion , yet there are still reasonable (if provisional) inferences that might be drawn from uses of it, and one can spot idiosyncratic occurrences. So we can talk about how the word connects up with other parts of our language, without ever really making it clear in your (idiosyncratic, proprietary) sense.

    The trouble is, you can do this sort of analysis without having any clue whatsoever as to the meaning: It would be equally applicable to the Maya codices.

    But we run into exactly the same problems with "love" that we do with "knowledge". A preliminary definition-free survey can take us only so far (not very far at all). To do more, we do in fact need to start constructing definitions, a necessary precondition to a precise theory.

    I think that almost three millennia is sufficient time to allot to such a preliminary survey.

    How do you imagine a scientific linguist's approach would differ from a philosopher's?

    A scientific linguist is interested in how we actually use language. A (good) philosopher is interested in how we can better use language.

    That's at least how I conceive philosophy. If you have a different view of philosophy, good for you. But don't complain that I'm doing philosophy "wrong" because it doesn't conform to your views or even the views of the entire academic philosophical community, of which I am not, nor will I ever be a member.

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  7. (Note: If you want to discuss what is or isn't "philosophy", this thread is not the place. Email me, or just wait until I post directly on the subject.)

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  8. Ron:

    It seems to me that it's quite easy to analyse yourself until you vanish up your own ass, and I feel that that's what some philosophers do when considering truth and knowledge. Maybe it's just my ignorance of some of the finer points.

    You are indeed ignorant of the finer points of philosophy. Were you aware of them, you wouldn't bother to qualify your opinion with "seems" and "feels". :-D

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