4 ms·

This is an excellent comment - I'm just disappointed you managed to say it all without the word "Bayesian". The base rate for paper mache cows in fields is very

by dTal 8y ago

This is an excellent comment - I'm just disappointed you managed to say it all without the word "Bayesian". The base rate for paper mache cows in fields is very low - one is perfectly justified in assigning a decent probability that a field contains a cow, if one sees a cow-shaped object in it. If you are in a part of the world that has a lot of cows in fields, you will presumably assign an even higher probability. You might even say you're "sure" there's a cow in the field, and act as such for everyday purposes. But don't be fooled - you're not really sure. If someone offers to bet you ten dollars versus your life that there is a cow in the field, you'll likely not take the bet. It seems that the philosophers were grasping towards a definition of "know" that encapsulated the idea of assigning 100% probability to something, after incorporating all the evidence. From a Bayesian standpoint, this is impossible. You can never be 100% certain of anything. To "know" something in the sense of "a justified, true belief" is impossible, because a belief is never both 100% and justified. (Note that it is entirely possible to see the paper mache cow and conclude that it is likely only paper mache and that there is not a real cow in the field. Is this belief "justified"?)

dTal 8y ago
I've thought a bit more about it, and concluded that while the above is a neat answer, it doesn't explain the question, and [thewarrior]'s remarks were nearer the mark on that. So here goes. It's tempting to think of "knowledge" as some relationship between the mind and a single fact. But when we use the word "knowledge", what we actually mean is "an accurate world model" - a set of beliefs. This is the disconnect that Gettier cases are designed to expose - they construct scenarios where someone's mental model is inaccurate or incomplete, yet by sheer luck produce a single, cherry-picked correct prediction. We are uncomfortable calling these correct predictions "knowledge" because as soon as you start probing the rest of the mental model, it falls apart. Sure, they think there's a cow in the field, and there really is one. Ask them any more questions about the scenario though ("what color is the cow?") and they'll give wrong answers. From this perspective, "knowledge" as a "justified, true belief" is a perfectly coherent concept - the problem lies with the inadequacy of the word "justified" to describe the output of a complex decision procedure that incorporates many beliefs about the world, such that it could be expected to yield many other correct predictions in addition to the one in question, up to some arbitrary threshold. A thought experiment - suppose you tell the observer that the cow they see is made of paper mache. They no longer believe there is a cow in the field. Intuitively, has their knowledge increased or decreased?

by dTal 8y ago

dTal 8y ago

I've thought a bit more about it, and concluded that while the above is a neat answer, it doesn't explain the question, and [thewarrior]'s remarks were nearer the mark on that. So here goes. It's tempting to think of "knowledge" as some relationship between the mind and a single fact. But when we use the word "knowledge", what we actually mean is "an accurate world model" - a set of beliefs. This is the disconnect that Gettier cases are designed to expose - they construct scenarios where someone's mental model is inaccurate or incomplete, yet by sheer luck produce a single, cherry-picked correct prediction. We are uncomfortable calling these correct predictions "knowledge" because as soon as you start probing the rest of the mental model, it falls apart. Sure, they think there's a cow in the field, and there really is one. Ask them any more questions about the scenario though ("what color is the cow?") and they'll give wrong answers. From this perspective, "knowledge" as a "justified, true belief" is a perfectly coherent concept - the problem lies with the inadequacy of the word "justified" to describe the output of a complex decision procedure that incorporates many beliefs about the world, such that it could be expected to yield many other correct predictions in addition to the one in question, up to some arbitrary threshold. A thought experiment - suppose you tell the observer that the cow they see is made of paper mache. They no longer believe there is a cow in the field. Intuitively, has their knowledge increased or decreased?