That particular conceit of the philosopher, "you cannot say anything about Covid-19 if you do not first have an implicit or explicit criterion of what truth iis" — Banno

It's not the philosopher saying it, it's common sense. How can you say there is a dog if you don't have a criterion to decide what is a true dog from a false dog? At least implicitly!
The philosopher will never say when a scientific statement is true or false. At most, he will say what the implicit criterion of truth that science uses means. And as I said, even theoretical physicists are interested in it. It's not just a philosophical mania.

Investigating truth will not tell you what to believe about Covid-19; for that, you will hav to investigate Covid-19. — Banno

But you cannot say anything about Covid-19 if you do not first have an implicit or explicit criterion of what truth is. Saying "Covid19 kills if and only if Covid-19 kills" does not make anything clear. The problem is how do I know if Covid-19 kills and to what extent can I know.
Quoting Tarski at this point seems pointless to me. Unless you explain it to me better.

Of course, having an implicit concept of truth usually works, but there are certain moments in life and theory where one has to ask oneself what is truth and what the problems of realism are. Ask Einstein and Bohr, for example.

Yes, it is - that's part of the point. "...is true" is banal. It adds nothing to what has already been asserted. — Banno

That is, it is merely analytical or formal. In that case, Tarski's criterion could not tell us anything about the existence of Covid-19 and the falsehoods that a certain ridiculous guy says about it in Twiter. What kind of criterion of truth is that? Or do you not believe that false things are said about Covid-19?

Yet the strategies within chess are objective - they exist regardless of whether a mind grasps them or not. The physical component of chess isn't relevant either: — BitconnectCarlos

What kind of objectivity are you talking about? You seem to believe that even if humanity, the planet, the galaxy and the known universe disappeared, the Sicilian Defence would still exist. Is that so? In what kind of reality?

Agreed, for in no other way is criterion for truth irreducible, then to the form to which all substitutions in it must adhere. If substitution violates the form, the substitution is false. — Mww

The substitution axiom is a mathematical axiom. I would like to know what it has to do with the existence of objects outside the mind and the possible knowledge of them. Can you explain it?
In my opinion pure mathematics needs transformation rules to become physical laws. Is the axiom of substitution one of them?

Absolutely. I’d even go one step further, to wit: is impossible. Still, pointless works, because if it’s pointless, being impossible doesn’t make all that much difference. — Mww

Covid-19 kills people.
Does it?
We don't care if it's true or not?

I suggest that a theory about truth is neither impossible nor pointless.

The formula is the new-fangled, analytic, thinks-it’s-better way of stating the continental version which claims, “...the definition of the word truth, to wit, the accordance of the cognition with its object... — Mww

Yes, correspondence theory of truth. Aristotle.
But limiting itself to the pure form of the proposition. If we do not epistemologically analyze what the object may be, we are not going anywhere in this thread at least.
Tarski's formula: P it is true if and only if p
The statement "The snow is green" is true if and only if the snow is green, is a banality from the point of view of knowledge of the world.

He's making a reference to logic. He's trying to show that logic can generate objectively true statements. — Cidat

Not really that relevant here; except that they are exactly right. — Banno

I still don't know what this is about. Especially if you add that it has nothing to do with this.

Anyway Tarski's definition of truth refers to the formal conditions of truth, which have little to do with truth as a relationship of the subjective and the objective. About exactitude of formal sciences we have a lot of theories. Our problem is our natural languages with their distinction objective-subjective. Science, for example.

"p" is true iff p — Banno

I don't understand anything. Could you explain it a little more?

I think T-sentences tell us pretty much all there is to know about truth. — Banno

"T-sentences"?

But when they get attached to truth and reality and such, they take us up the garden path. — Banno

May be that the problem is not in the concepts, but in the ideas we link to them.
Or maybe the problem of truth is complicated in itself.

I know what chocolate cake is. I'm not so sure about an idea-of-chocolate-cake. Is it a thing? A thing in my mind? But then is the thing in my mind the very same as the thing in your mind? — Banno

Try eating the idea of a cake and you'll see the difference.

It's another thing whether ideas, which are not eaten, can correspond exactly to the thing outside. This is a very serious problem, but it is based on the fact that you must make the distinction between objective and subjective first. If you don't want to do that, apart from starving yourself, then answering the second question is meaningless. If you do the distinction the problem arises alone.

This thread is just a collective stream of consciousness. — emancipate

Have you seen one that isn't?
Not all debates are like internet forums. Some are even cooperative, orderly and respectful of others' opinions. Very boring.

I'm not following the distinction you wish to make. — Banno

Sorry, are you discussing types of ideas or the concept of truth? They're two different problems. If we mix them up we'll have a mess. Of course.

I want to distinguish between two kinds of realities: one is ideas and the other is objects. The distinction is that if I think about a cake something happens inside my mind not outside and if my mother makes me a cake it's outside my mind. Fortunately.

How do you distinguish between the two things? That is, the idea of a cake and the cake itself. You have to do it whether you want to or not. Otherwise you risk to perish of starvation.

Yep. It's what I do. — Banno

How do you distinguish between ideas that refer to things outside of your mind and others that are entirely subjec... sorry, that have no external reference? I think this is an epistemologically inevitable distinction that is usually made by distinguishing subjective and objective. What is your choice? You're defending solipsism?

But for me, “reality” is merely the noun form of the adjective “real” which, in turn, is intended to signify “actually existing or occurring - rather than fictional” — javra

But if you use the same term to designate what is inside your mind and what is outside it, you will have to give additional explanations to avoid possible misunderstandings. The main explanation is that there are two types of reality, the subjective one, which occurs in your mind, and the objective one, which occurs outside it. You will have to correct the concept of truth, which will have to distinguish between a subjective truth and an objective truth. All this is easier resolved if we speak of objective and subjective and if we limit the concept of truth to the correspondence with something external to the ideas of my mind, this is to say, the reality. Or as a property of certain type of propositions, which is a formulation I like better.

As far as intersubjective reality is concerned, you should make it clear that it only refers to the fact that certain people share certain ideas, which is very different from those ideas referring to something outside their minds.

So many previous clarifications hinder a discussion that it would be easier if you used the terms as they are usually used in the field of philosophy. No one is forcing you to do this, but it would pave the way.

If you refer to yourself as a "subject", and others refer to you as an "object", are we both talking about the same thing, or are we talking past each other? — Harry Hindu

No one can talk about me from my point of view, strictly speaking. But the other one doesn't talk about other person. He sees me from another point of view and this is me too.
But the point is how to bridge the gap between the two "I's". The answer is not in the wind of words but in common practice.

So how do you reconcile the facts that you are a subject from your perspective but an object from other's perspective when we all share the same world? — Harry Hindu

Reconcile? It's a fact that I'm an object for others. Two points:
The perception of the other as someone who looks at me implies that I perceive them as another consciousness in the same world.
And we can feel that we have a common existence in the fact that we can share the same project. That is, in practice.

Therefore, intersubjectivity is not a feature of consciousness alone, but of human existence as a whole. It begins with language and continues in acts. Or vice versa.

The reference would be the subjectively perceived phenomena? — Echarmion

Directly, yes. In the second instance, objects constructed as handfuls of sensations under a form.

The point is that this reality is not objective, but subjective even though it is related to others through language.

Example:
Peter and Paul are seeing something flying in the sky.
What is that?, says Paul.
Peter: I don't know.
Paul: It has the shape of a son of man.
Peter: Yes, and it has a red cape.
Paul: And red underpants!
Peter: Yes, and blue tights!
Paul: It wasn't a bird, it wasn't a plane! Was it Jesus?
Peter, Paul & Mary: No! He's Superman!!!

How they arrive at a common proposition? By referring to their respective subjective impressions. Objectivity is absent from the dialogue. Only intersubjectivity.

Ok, so would it make sense to say that "intersubjective reality" is a set of propositions about phenomenal reality shared by a group of subjects? — Echarmion

I suppose that would be a shortened way of referring to the reference of an intersubjective proposition. Is that so? I would understand it like that.

I’ll add that, to me at least, if these categories of “personally subjective realities”, “intersubjective realities”, and “the singular objective reality” are taken to be valid, — javra

I guess "intersubjective reality" is a metaphor. What's intersubjective is the proposition. We share it or we don't share it. The enunciated means a state of facts. I do not share those facts with the others. They can exist in a world that is not mine, but nevertheless I can share the same statement. This is what makes it intersubjective.

Example:
Imagine a man who has an optical problem from birth and sees the colors red and blue interchangeably. When we are together we both say "This is red and that is blue" in the same way, that is, we point out the same things. Each of us will really be seeing something different subjectively, but we will say the same thing. Our statement is intersubjectively the same. And that's what matters.

While imaginings and delusions are real and objective in the sense that they exist, — Harry Hindu

Generally, in philosophy the concept of objective is reserved for knowledge that refers to what is outside the mind of the subject. It can be forced to mean that in introspection the mind is both subject and object, but this is an exception to the rule that should be emphasized so as not to create confusion.

Then they are revised until complete accuracy is achieved. — Templisonanum

This seems to be the easiest solution, but it is not so easy in practice. The process of refutation of a theory never involves a single theory but a set of theories that include the basic and secondary ones. The scientist's dilemma is which of them to reject. For this dilemma there is no algorithm. It is intuitive and there are some extra scientific implications. This uncertainty explains the changes in the laws that are even considered essential for science.

Therefore, accuracy in science is relative and objectivity is never assured.

Metaphysical inquiry can lead to the theory of the undivided particle - the monad, which as we know from physics to be true, from observing elementary particles. — Templisonanum

Leibniz's monads and Democritus' atoms had nothing to do with the contemporary concept of atomic particles. They were speculative. Their characteristics were not empirical. They had no extension, for example. And according to the ancients, they spawned numbers. You're a rational monad, you see.

For the same reason you cannot say that Jules Verne "advanced" to NASA interplanetary travel. (Actually, there is more distance between Leibniz and Bohr than between Verne and Gagarin)

Can you point out to me what I did wrong? — Echarmion

The term intersubjective does not refer to means of expression or objects, but to properties of knowledge or propositions, to be more exact. The internet forum is not itself intersubjective, but the content that is expressed through it. You can make statements that are based on something that actually exists (objective), on a merely personal appreciation (subjective) or on a reference that you share with a more or less wide group of people (intersubjective).

As I said, neopositivism and philosophical analysis exclude the first option. An intersubjective proposition is close to objectivity when admitted by everybody, but it is not the same concept.

You can make a personal use of the word. But you should know how it is used in contemporary philosophy to avoid confusion.

Then the philosophers become involved... and off we go up the garden path. — Banno

Don't blame the philosophers. There is no philosopher here and things are messy enough.
In my opinion, we ordinary people have more problems with words than (some) philosophers (not all).

The objective part here is that we're somehow exchanging information. The intersubjective part is that we're using an Internetforum, computers, the English language etc. And then we each have a subjective interpretation of what is said and why, with a small model of what the person saying it might be like. — Echarmion

I'm sorry, but your use of intersubjective is incorrect.
An objective proposition corresponds to the external objects.
The proposition that depends on the subject is subjective
The proposition that is common to several subjects is intersubjective.

The term intersubjectivism was introduced by the Vienna Circle (Carnap) to overcome the metaphysical problem of objectivity and solipsism
See A. J. Ayer: Language, Truth and Logic. Alternative: http://www.informationphilosopher.com/knowledge/inter-subjectivism.html

The proposal seems reasonable to me: since strict objectivism is impossible, we defend knowledge that is based on basic propositions, that is intersubjective. This does not mean that it is free of problems. Although it avoids metaphysical problems, it has some difficulties.

On really existing democracy, not the ideal one, I recommend Noam Chomsky's Fear of Democracy. Basic reading. In my opinion the so-called democracies are really plutocracies tempered by the necessity of propaganda.

On the democracy of science I recommend trying to publish a text in a scientific journal and considering whether the filters are democratic or dependent on power cliques. And I suppose we are talking about the factual sciences. In social sciences is worse.

Science has epistemological rules that depend on the intellectual capacity of those who develop them and a social development that depends on the powers that govern society. None of them are democratic. If anyone thinks that those powers are "the people", I think he is an idealist.

As if subjectivity made sense without objectivity. — Banno

I have not understand well.

One can drop with word "objective" without loss: "What is the way to know if we have reached a truth" — Banno

We can also talk about "subjective truths".

There is no reason to think that there is exactly one answer to this question; — Banno

There are some differences according to the different branches of knowledge but it is possible to draw a scale of objectivity. The so-called factual sciences are at the top. (Formal sciences are not objective).

In general, objectivity is related to prediction. We say that "boiling water burns" describes objective facts because we do not know any exceptions to it. We can predict "objectively" what will happen if someone puts a finger in the pot of boiling water.

This seems very simple, but it starts to get complicated when we go to less simple propositions and theories than that. Mainly, because in science we cannot test isolated propositions, but a complex of theories and facts.

Obviously, all this disappoints the metaphysicist who is looking for absolute objectivity or certainty. A chimera.

Objectivity is possible through analysis, prediction, and success — Templisonanum

It is not exact. Many theories in the past were predictive and are considered false today.

This is the question:
What is the way to know if we have reached an objective truth?

Yes. And Messi is the best football player in the world.

So I truly and objectively believe I am more objective than they are. — Eugen

I'm sure they will think otherwise.

What matters in a discussion is not "true objectivity," whatever that means, but the depth to which beliefs are rooted and the rhetorical capacity to make arguments that sound fine.

In a discussion everyone talks to themselves as this brief exchange between you and me shows. Have you ever thought that you were wrong? Ask yourself.

The examples you propose are accompanied by answers you propose. So you are always more objective than your opponent... according to your subjective criterion of objectivity.
But the problem I was raising with you concerns issues that are basic to a belief system. There the different positions, yours and your opponent's, are no longer objective and are based on principles that are not objective. For example, what is better communism or capitalism? Which is better, a system that favors equality or a system that favors individualism?

This is the kind of discussion that your opponent can most easily engage in. He will probably reject your criteria and divert the discussion into preferences rather than rational arguments. That is why the discussion never ends with the basic beliefs of either party. It can be said that there are no winners or losers.

Why aren't we able to change ingrained beliefs through discussion? Because ideologies are not just belief systems but ways of life. They are anchored in our personal and public relations, our economy and our desires and hopes. In other words, our life project. Changing a basic belief means changing one's concept of oneself and one's position in the world. And this is not the same as recognizing that two plus two does not always make four.

It is either life itself that pushes you, or you have to be brave.

I consider myself rational when, for example, I say communist Romania was far worse than nowadays Romania — Eugen

USSR broke because its economy collapsed. — Eugen

A "true communist" will discuss this conclusions in many ways, usually refusing to accept that Ceausescu was a communist or blaming the USSR leadership for having abandoned a true communist economy at one time or another. These are not hypothetical cases. I have argued with "real communists" many times and I know them well. I never convinced any of them.

I'm not going to launch an argument about communism with you. This is not the time to do that. Just one thing: don't hasten to shoot the " true communist". "True Christians", "true democrats", "true neoliberals" and a lot of "true this or that" are the same thing."Truism" is a very common plague that no one wants to admit to being infected with. So are you and I.

Debates serve only one purpose: to refine our basic beliefs... if you have an open mind. If you are an open-minded man (that is, you are capable of revising your basic beliefs, -a rare specimen of humanity), reality will most likely change them. Not a "fool" who contradicts you.

Go into any forum and see.

If you're trying to convince someone that 1+1=55 you will eventually convince him, it's just a matter of time. — Eugen

I assume we're talking on essential beliefs of a person's original project or basic ideology. These beliefs are not usually based on rational logic but on psychology and a complex mix of desires, fears and rationalizations. This is valid for fanatics but also for moderate people. The Cartesian rational man is a myth.
Reasons only convince someone who wants to be convinced.

Thomas Kuhn said that scientific paradigm changes never happened because they convinced the proponents of ancient science, but because they died. If this is in a rational field like science, you can imagine in morality or politics. The USSR did not fall because of the moral superiority of the arguments for democracy, but because the communist leaders realized that they could make more money from capitalism.

If people cannot be bothered to challenge their own fundamental beliefs, why would they every think that that someone else might be persuadable? — Pantagruel

That is a good question.
I think the selfish impulse is the answer. The guilty ones are the others and the others are wrong. Never me. Lucidity is a rare virtue.
It remains to be seen what part insecurity plays in this. Deep down, the dogmatic man is suspicious of himself.

Of course. Provide them with proof that they are wrong and that you are right. — Tzeentch

I think an equally interesting question is, can/do people change their own deeply rooted beliefs? — Pantagruel

Too optimistic. The fact that the greatest scientists of the 20th century were discussing the principles of quantum mechanics for decades and none of them substantially changed their opinion seems to be a bit discouraging.