The term 'true' is used in a certain context though:

1.1 The Truth Condition
Most epistemologists have found it overwhelmingly plausible that what is false cannot be known. For example, Hillary Clinton did not win the 2016 US Presidential election. Consequently, nobody knows that Hillary Clinton won the election. One can only know things that are true.

Sometimes when people are very confident of something that turns out to be wrong, we use the word “knows” to describe their situation. Many people expected Clinton to win the election. Speaking loosely, one might even say that many people “knew” that Clinton would win the election—until she lost. Hazlett (2010) argues on the basis of data like this that “knows” is not a factive verb.[2] Hazlett’s diagnosis is deeply controversial; most epistemologists will treat sentences like “I knew that Clinton was going to win” as a kind of exaggeration—as not literally true.

Something’s truth does not require that anyone can know or prove that it is true. Not all truths are established truths. If you flip a coin and never check how it landed, it may be true that it landed heads, even if nobody has any way to tell. Truth is a metaphysical, as opposed to epistemological, notion: truth is a matter of how things are, not how they can be shown to be. So when we say that only true things can be known, we’re not (yet) saying anything about how anyone can access the truth. As we’ll see, the other conditions have important roles to play here. Knowledge is a kind of relationship with the truth—to know something is to have a certain kind of access to a fact

https://plato.stanford.edu/entries/knowledge-analysis/#KnowJustTrueBeli

The man and his ID with his name and his photograph probably correspond in all fairness. But there is a chance he is wearing a fake face, or his ID is falsified.

Likewise, seeing a dog shape in the mist can be a person wearing a dog costume. A leaf floating in the wind can be taken for a weird bird. If I see giant horses in clouds jumping from behind a forrest, I will soon become aware that it are clouds. Unless I reject their physical status altogether and give them a place in a magical approach to reality.

Why should what is false cannot be known? It can just as well be known as what is true.

Something’s truth does not require that anyone can know or prove that it is true. Not all truths are established truths. If you flip a coin and never check how it landed, it may be true that it landed heads, even if nobody has any way to tell.

Why is it necessary to believe that a flipped coin assumes a definite state of affairs before checking? This assumption only appears to be necessary relative to the commonly accepted assumption that causality is asymmetrical in which causes must precede effects. But this assumption isn't empirically testable.

Instead, if causation is treated symmetrically, in the sense of allowing both forward and backward causation, then the act of checking the outcome of a flipped coin can be freely interpreted as forcing the past state of the coin to assume a definite state of affairs.

Consider for instance a video game that dynamically generates a dungeon around a player in response to the player's movement. This demonstrates that backward causation is a valid empirical notion, even if the game's underlying implementation involves only forward causation.

Any examples that cause problems for the JTB theory of knowledge? — TheMadFool

Here’s an “example” I thought of, and am curious about its implications. I’m not really sure how I feel about it. Anyways, here goes.

You make plans to meet a person you’ve never seen before over the phone (for whatever reason you can come up with). Through the phone call you know that this person is male, middle aged, and named Bob. Bob tells you he will be at restaurant X on Wednesday at 6pm, and that he’ll be wearing a blue shirt. You go to restaurant X at 6pm on Wednesday, see a middle aged man in a blue shirt, whom you assume is named Bob. You approach the man and ask if his name is Bob, and it is. However, it isn’t the Bob you’re supposed to meet. Was your belief that the man in the blue shirt’s name was Bob knowledge? It seems to be a JTB, but only coincidentally. But does that matter? It also seems to be just an issue with language. What exactly is meant by the term “Bob?” If it has the stricter meaning of “the person you’re supposed to meet” then you believing the man in the blue shirt is Bob is technically false, because it’s a different definition of the word “Bob” than the one you had in mind.

Knowledge is being defined as justified true belief, not just as justified belief. — Michael

Yeah, I think that’s a key point that is often overlooked.

The issue is obviously with what constitutes justification. But JTB is not concerned with establishing criteria for that; it is just a definition based on analyzing what is usually meant by knowledge. We don't have to know what constitutes justification (every case will be different) in order to understand the definition.

In the 'bartender' case; his belief the person is 18 is not justified because it is based on a fake id. So it is not knowledge (specifically "knowledge that", not "know-how" or the knowledge of familiarity or acquaintance). The fact that the person is 18 is irrelevant,

This brings up an interesting point about this case; we might want to say that if the id had been valid his belief would have been justified; but if there is no way to tell whether an id is false or not, then there can be no knowledge in the JTB sense in either case, and a rational person would suspend judgement and make no claim to believe the person is 18, as opposed to accepting that the person is 18 in the sense that a box has been ticked. If you asked a rational bartender whether they ever know anyone is 18 they would say 'no'.

If it turns out that we never have justification to believe anything, then we never have knowledge, but just belief. The definition of knowledge as JTB remains untouched in any case.

In the 'bartender' case; his belief the person is 18 is not justified because it is based on a fake id. — Janus

What do you mean by a belief being justified? Because I understand it as meaning that, given the information available, a rational person can cogently infer the subject of belief. As such, a fake ID can be justification.

This, incidentally, is how the law would consider it.

What do you mean by a belief being justified? Because I understand it as meaning that, given the information available, a rational person can cogently infer the subject of belief. As such, a fake ID can be justification.

This, incidentally, is how the law would consider it. — Michael

Depending on how you want to think about it, you could claim that any belief is not justified, since it is not absolutely certain. The acceptance of fake ids as proof of age is legally justified, since it is acknowledged that the average bartender does not possess the means to enable her to distinguish between a fake id and a valid id. But if you don't have the means to distinguish fake from valid then you have no justification in claiming knowledge.

Depending on how you want to think about it, you could claim that any belief is not justified, since it is not absolutely certain. — Janus

Why does justification require absolute certainty? The Cambridge dictionary defines it as "having a good reason for something" which is consistent with how I defined it and how I ordinarily understand it in everyday conversation.

If justification required absolute certainty then defining knowledge as justified true belief would be redundant; it might as well be defined as simply justified belief.

Gettier was arguing against those who claimed that knowledge is justified true belief, and such people accepted that there is such a thing as justified false belief, hence why they explicitly included being true as a separate condition to being justified. Disagreeing with what such people mean by "justified" seems to be missing the point. We can simplify it by saying that such people argue that one has knowledge if one has a true belief that one has good reasons to believe, and Gettier provided examples of where one has a true belief that one has good reasons to believe but that we wouldn't consider knowledge.

The fact that you seem to require certainty for knowledge shows that, rather than your prior claim that "there is no problem for JTB", you in fact agree with Gettier that the JTB definition of knowledge is deficient.

If it turns out that we never have justification to believe anything, then we never have knowledge, but just belief. The definition of knowledge as JTB remains untouched in any case. — Janus

Flatearther have 'knowledge' that the Earth is a disc then. If that is how we're defining 'knowledge' in JTB you can have it.

The problem with the Justification you outline shows that what is referred to as 'knowledge' is PURELY subjective according to how you put JTB.

Holding to the JTB definition of knowledge is what people with opinions do as it doesn't require proof or truth, merely a connection to something that could be true due to some evidence.

Humans are fallible. The point of 'knowledge' (correct me if I'm wrong) is to counter our fallibility. Therefore it is nonsense to frame 'knowledge' as something defined by the whim of an individual human. An annoying paradox only resolved by the use of abstract 'knowledge' (knowledge confined to certain universal parameters).

The fact that you seem to require certainty for knowledge shows that, rather than your prior claim that "there is no problem for JTB", you in fact agree with Gettier that the JTB definition of knowledge is deficient. — Michael

I didn't say I endorse that view. Read it again: "

Depending on how you want to think about it, you could claim that any belief is not justified, since it is not absolutely certain. — Janus

JTB is just a definition and says nothing about whether we actually do have knowledge. If we do have knowledge then we do have justified true belief, according to that definition. It also says nothing about what would qualify as justification. Saying "having good reasons" doesn't ell us what would qualify as good reasons, either.

Flatearther have 'knowledge' that the Earth is a disc then. If that is how we're defining 'knowledge' in JTB you can have it. — I like sushi

You continue to misunderstand. Flatearthers do not have knowledge that the Earth is a disc, because it is not true that the Earth is a disc.

You continue to misunderstand. Flatearthers do not have knowledge that the Earth is a disc, because it is not true that the Earth is a disc. — Janus

I understand perfectly well. You do not.

Get it?

How could the theory that the world is a disc possibly be an example of JTB, if it is not true? :roll:

Because it is true for those that believe it. Look at how the T is used in the definition - we are not able to say what is or is not true outside of abstractions. We cannot say some element of reality is true only that we have evidence that suggests it is true, hence:

Knowledge is a kind of relationship with the truth—to know something is to have a certain kind of access to a fact

https://plato.stanford.edu/entries/knowledge-analysis/#KnowJustTrueBeli

What we call true is based on the justification for it being true (evidence). So outside of abstract contents we are limited and do not have access to ALL information (we are not omnipotent).

Everything in life is a JB and in abstraction we can have JTB if we can handle the size of the data set and fully understand the rules.

https://www.youtube.com/watch?v=w11mI67R95I

I've heard people say, "[...]discover knowledge".

Does that mean knowledge is distinct from knowing?

If we can "[...]discover knowledge" it means the definition of knowledge is:

1. A true proposition P
2. P is justified [in two minds about this condition]

or something like that.

Discovering knowledge then amounts to believing P (is true) and working out its justification.

Also from your link, immediately prior to your quote:

Something’s truth does not require that anyone can know or prove that it is true. Not all truths are established truths. If you flip a coin and never check how it landed, it may be true that it landed heads, even if nobody has any way to tell. Truth is a metaphysical, as opposed to epistemological, notion: truth is a matter of how things are, not how they can be shown to be. So when we say that only true things can be known, we’re not (yet) saying anything about how anyone can access the truth.

Whether or not the Earth is flat has nothing to do with whether or not anyone believes that the Earth is flat. The Earth isn't flat, and so flat-Earthers do not have knowledge that the Earth is flat. They in fact have an unjustified false belief.

No. This was an extreme example put forward for impact. They most certainly do have Justification or why would they believe that the Earth is flat?

My point here being is that people may have different reasons to consider different pieces of evidence. It is hard for me to imagine that the Earth is flat but at a glance we cannot generally ‘see’ that there is curvature to the Earth. We are in a position to say that this is false now but if we lived in the hills and had never seen the ocean nor knew of space and the heavenly bodies much would we view it as ‘True’ that the Earth was flat.

This is not the same as saying scientific knowledge has moved in from Newtonian motion to the theory of Relativity. Newton was just less accurate. I have no direct knowledge other than belief in an abstract system that does a damn good job of modelling the world.

My trust is based in mathematics not my ability to do mathematics accurately.

Do you not see that there are lines between what one person would claim as ‘good evidence’ and state something as ‘true’ where others would disagree and hasten to show them otherwise ..l like right now with me making as plain and clear as I can that what is considered ‘true’ in the lived world is open to some degree of doubt - where 1+2=3 is arithmetically correct and holds to a set of rules made by humans and understood universally. I do not ‘believe’ 1+2=3 I know it (but I know it as an abstract fact not as a reality as my scope for what the universe contains is limited and I have no idea if their are constant ‘rules’ and/or how many there are if there are any that I could comprehend.

JTB can function if Ockham is brought in. Which would basically make the whole JTB idea reliant upon another kind if ‘hedge your bets’ version of what ‘knowledge’ is.

what is considered ‘true’ in the lived world is open to some degree of doubt — I like sushi

What is considered to be true and what is actually true are two very different things. I can believe that something is true and be wrong. Knowledge requires both that we believe that something is true and that that thing is actually true (and that our belief is justified).

This is why flat-Earthers do not know that the Earth is flat. Even though they believe that it is true that the Earth is flat, it in fact isn't true that the Earth is flat.

I’m confused? Why are you missing/avoiding my point.

What you and I may deem to be an obvious and proven truth today may turn out to be partially/completely wrong in several generations. We are not privy to the machinations of the universe merely part of them. We can interpret our minuscule corner reasonably well, or so we believe … which is my point.

The abstract does not match reality. So iff P then S is merely an abstract fact that can help guide us in reality but it sure as hell is not reality.

It appears we merely mark out the kind of ‘truth’ you are talking about by approximating it with abstract knowledge. Just because from some individual perspective we’re lined up with some abstract truth that correlates with reality it does not make it true in any absolute sense. Truth in reality is always our best educated guess backed up by evidence we also believe to be worthy. We cannot know anything with certainty unless we are limiting it and applying strict rules (eg. Playing Chess).

If we have no knowledge of the rules of chess and watched several hundred games could we say with 100% certainty that we understand ALL the rules of the game. Absolutely not. We would probably believe that we have enough experience to play the game well enough though. If we never saw what happens to a pawn once it reaches the other side of the board do we truly understand all the rules of chess? No. Are we justified by watching several games to assume we do understand all the rules of chess? No, but if we had to reach a conclusion with what we’d observed we might well say ‘now I know how to play chess’.

Reality, unlike chess, does not possess a handy rulebook and nor do we have access to the entire board. To state that this rule is ‘true’ or ‘false’ based on a limited scope is just referential to the idea that there is a ‘True’ and a ‘False’ not evidence that there is - in reality - a ‘True’ or ‘False’ other than that which we make via abstraction and strictly defined boundaries we imagine.

What you and I may deem to be an obvious and proven truth today may turn out to be partially/completely wrong in several generations. We are not privy to the machinations of the universe merely part of them. We can interpret our minuscule corner reasonably well, or so we believe … which is my point. — I like sushi

That has no bearing on what it means to be true. Either the Earth is flat or it isn't. It can't be both. It can't be neither. It can't be flat for some people and not flat for others. Either the people who believe it to be flat are wrong or the people who believe it to not be flat are wrong.

If the Earth is flat then nobody can know that the Earth is not flat. If the Earth is not flat then nobody can know that the Earth is flat.

Perhaps drop that extreme example and deal with something more subtle then. The problem is still there.

There is no problem. If aliens exist then nobody can know that aliens don't exist. If aliens don't exist then nobody can know that aliens exist. It's very simple. Whether or not something is true is independent of our beliefs, and knowledge requires truth. That's why the JTB definition of knowledge has three conditions, not just two:

1. I believe that X is true
2. I am justified in believing that X is true
3. X is true

1 and 3 are not the same.

Take P1 to be 'I know the earth is flat'. We'd like to be able to say P2 'I thought I knew the earth is flat, but I was wrong, the earth is not flat'.

But P2 is contingent on knowing that the earth is not flat. Otherwise it's merely 'I thought I knew the earth is flat, but I think I was wrong, I think the earth is not flat'

So what's 'I know' doing in the expression?

How does...

'I thought I knew the earth was flat, but now I think I know it's not flat'

...differ from...

'I thought the earth was flat, now I think it's not flat'?

JTB seems to do away with 'know' meaning anything at all.

Take P1 to be 'I know the earth is flat'. We'd like to be able to say P2 'I thought I knew the earth is flat, but I was wrong, the earth is not flat'. — Isaac

If P1 is true then P2 is false; if P2 is true then P1 is false.

But P2 is contingent on knowing that the earth is not flat.

It's not. Consider this example:

1. I thought I knew that aliens exist, but aliens don't exist

The above statement can be true even if I don't know that aliens don't exist.

1. I thought I knew that aliens exist, but aliens don't exist

The above statement can be true even if I don't know that aliens don't exist. The above statement is true if aliens don't exist and if in the past I thought that I knew that aliens exist. And, of course, the above statement is false if aliens exist. — Michael

Indeed. But that's not the question I asked. To use your example, how does...

1. I thought I knew that aliens exist, but aliens don't exist

...differ from...

1. I thought that aliens exist, but aliens don't exist

To use your example, how does...

1. I thought I knew that aliens exist, but aliens don't exist

...differ from...

1. I thought that aliens exist, but aliens don't exist — Isaac

In the first case I'm saying that I believed my prior belief was justified and true, whereas in the second case I'm saying only that I had a belief.

In the first case I'm saying that I believed my prior belief was justified and true, whereas in the second case I'm saying only that I had a belief. — Michael

So, if you ask 'where's the pub?' and I say 'I think it's at the end of the road', I'm implying that my belief is neither justified nor true?

If so, why on earth would I have said it?

So if something is ‘justified’ it is ‘true’? Do you believe that people who believe they are justified to claim something as true are only justified by how you depict what is true?

This isn’t rocket science. We cannot know what is true without preset parameters and rules. The universe is not something we have complete knowledge of therefore its ‘rules and parameters’ are unknown so our justification for any truth (outside the abstract) is open to varying degrees of doubt. We have ‘justification’ for beliefs when we can apply logic and reason (abstract tools) that adumbrate some supposed ‘truth’.

From here it doesn’t take much of a leap to understand that people with varying experiences and understandings may arrive at different conclusions as to what is or isn’t considered ‘knowledge’ because they are not privy to every possible perspective or the full comprehension of the manner in which nature operates.

JTB as a definition of ‘knowledge’ is open to personal interpretation (it is a subjective definition of knowledge because two different people could dispute what is or is not ‘true’ by way of how they ‘justify’ said claim.

If aliens exist then nobody can know that aliens don't exist. If aliens don't exist then nobody can know that aliens exist. It's very simple. — Michael

It is very simple for me to point out that WE DON’T KNOW EITHER WAY. Speculation about the actual existence of extra terrestrial beings is just that. I possess knowledge that seems to suggest to me that such beings do exist but I don’t actually know one way or the other.