But there is a difference between knowing the truth and the truth. And to say that P is probably true is not to talk about the kind of truth P has (which you seem to think it is) but to talk about the evidence we have that it is true. There are not two kind of truths, probable truths and non-probable truths. What is true is true, and what is not true is not true. And there are truth we know, and truths we do not know. But that has nothing to do with whether or not they are true.

If we know that P is true, then, of course, P is true. But if P is true, we may, or may not know that P is true. So, knowledge implies truth, but truth does not imply knowledge. There have been many truths people did not know were true, and there are, doubtless, now, many truth people do no know are true, and may never know are true. Obviously, it does not follow from the fact that no one knows whether P is true, that P is not true, so from the undoubted fact that you can give examples of propositions no one knows are true, it does not follow that they are not true, nor that it is not probable that they are true.

richrf,
Practically, most "truths" are probability. You can set up all the formal logic truth tables you want and I'll show you countless incidents where you can't "know" the "truth".

Yes, we are very much in agreement. I take the route of just letting people know up front that I am pretty sure, or possibly sure rather than take the posture of absolutely sure. Throughout my life I am continually surprised by new events that I could not have imagined previously. Readings on quantum mechanics were mind-boggling. The Aspect experiment on non-local interaction is the one that struck me as most spooky as well as the delayed choice double slit experiments where the slit choice was made after the photon had presumably passed through the slits. Super spooky stuff.

Rich

If 'knowing that p' isn't probabilistic, then there shouldn't be a possibility of being mistaken - even if p is a contingent proposition. To say:

I know that p

and

Both p and possible ~p

is to conflate the indicative of 'knowing that...' with the counterfactual of the contingent proposition p.

If "know" means it is in fact true, it cannot turn out later to be false. If to know something is to believe something to be true that is in fact true, then to possess knowledge is to possess the truth. The indicative of p - not how p might have been.

In the quantum world logic breaks down and nothing is certain.Heisenberg Uncertainty principle.

If we only perceive a tiny aspect of reality and at the quantum level everything is uncertain, how can we ever difine absolute truth?

The Uncertainty Principle

First published Mon Oct 8, 2001; substantive revision Mon Jul 3, 2006
Quantum mechanics is generally regarded as the physical theory that is our best candidate for a fundamental and universal description of the physical world. The conceptual framework employed by this theory differs drastically from that of classical physics. Indeed, the transition from classical to quantum physics marks a genuine revolution in our understanding of the physical world.


One striking aspect of the difference between classical and quantum physics is that whereas classical mechanics presupposes that exact simultaneous values can be assigned to all physical quantities, quantum mechanics denies this possibility, the prime example being the position and momentum of a particle.



According to quantum mechanics, the more precisely the position (momentum) of a particle is given, the less precisely can one say what its momentum (position) is. This is (a simplistic and preliminary formulation of) the quantum mechanical uncertainty principle for position and momentum. The uncertainty principle played an important role in many discussions on the philosophical implications of quantum mechanics, in particular in discussions on the consistency of the so-called Copenhagen interpretation, the interpretation endorsed by the founding fathers Heisenberg and Bohr.


This should not suggest that the uncertainty principle is the only aspect of the conceptual difference between classical and quantum physics: the implications of quantum mechanics for notions as (non)-locality, entanglement and identity play no less havoc with classical intuitions.

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My goodness. How does it happen you believe all that is true? Like many people, even radical skeptics, you seem to know is true what you choose to know is true. It depends on what it is you are arguing at the time. You like it for that "super spooky stuff" to be true, so that isn't just perspective so far as you are concerned. Is it? It fits right in what you prefer to believe is true. It is really amusing.

This should not suggest that the uncertainty principle is the only aspect of the conceptual difference between classical and quantum physics: the implications of quantum mechanics for notions as (non)-locality, entanglement and identity play no less havoc with classical intuitions.

:lol:All of this is opinion. Everything I write on this forum is opinion. Everything I ever say is opinion.



Rich

And how about your opinion that Niels Bohr was a physicist? Was that true, or was that true only in your opinion? Any perspective on that? You contradict yourself as you speak.

Everything I say is qualified that I realize that I can be mistaken, as I often am.

Rich

Well, we are all fallible beings. That is the source of the saying, "to err is human". So, most people recognize that you are, like them, and like most people, liable to error. But, sure. If you want to emphasize your modesty, by all means. Although, I imagine that like everything else of that kind, it can get to be a little wearing on those who know you. Charles Dickens creates a character in David Copperfield who goes overboard in his "humbleness". Uriah Heep (the name tells the story) who is ever so "umble" and self-effacing, that it begins to smack of insincerity, until at the end, the reader is just about ready to punch him in the nose for being so "umble".

Fine. What ever works for you.

Rich

O.K. What works for me is to call you, "Uriah". But why would you mind, since you are ever so "umble", and you understand my perspective. Someone like you should never be offended. It would be against your principles.

It's totally, absolutely fine with me.

Rich

What do you know then, besides the referent truths which are known, by definition, through reference?

I'd like examples.

I had parents
I was born
I am alive

Earth is the third planet
Quito is the capital of Ecuador

By definition these things have to be true for you to exist; your existence presupposes these truths. I'd call these self-evident.



These are the truths I'm referring to when I say "referent truths". There is intersubjective consensus on what "planet" and "capital" mean, and a reference to verify e.g. the city hall, an astrology text, scientists, etc.

Good, now let's approach analytic truths. Can analytic "truths", like the temporal placement problems we spoke of earlier, be known? If so, how? And please be descriptive with an example. Thanks.

I don't have to be born to exist. There is the phenomenon of parthogenesis. And I don't have to have parents to exist. So my existence does not presuppose these truths.

There may be intersubjective consensus about what planet means. But that is no reason to think that Earth is the third planet from the Sun. And this is not astrology. It is astronomy. Astrology is different

And the fact that there is a city hall in Quito doesn't make Quito a capital city. First of all, your must mean something like a capitol building. City halls are in citys, not capital cities. Much more important, the capitol building is in the capitol city because it is the capitol city. The capitol city is not the capitol city beccause the capitol building is in it. You have the cart before the horse.

Could you now possibly tell me where you are going with all this. If anywhere?

As far as I know, parthogenenis has never occurred with humans. So, for you to exist as human, you must have been born. And, as far as I know, human children are born from human sperm cells and eggs, coming from male and female humans. The male and female humans whom the sperm and egg came from would be regarded as your biological parents. So how does your existence as a human not presuppose these truths?



My apologies. Wherever you would verify "Earth is the third planet from the Sun".



Fair enough. Where ever you would verify "the capital of Ecuador is Quito."



If you have no idea where I'm going with this you obviously haven't read the past paragraphs written. And not just my paragraphs - practically everyone that has typed here thus far!

The vase problem was an example of the type of "truth" I'm referring to. You still haven't stated how you know the vase is on the table given the theoretical scenario. How can "truth" be verified by the vase example?

One thing is clearly true, however; if the vase is not on the table, then I cannot know it is true that the vase is on the table.

If you could never verify if the vase was on the table or not, you could never declare "knowledge". If you cannot declare "knowledge" about the vase, then you cannot declare "knowledge" regarding a multitude of things which you cannot consistently verify. If we agree on this, then we are limiting the usage of the word "knowledge" to only those things we can verify are true, like the capital of Ecuador. This means that unless we reference and define a "truth", we can never know it!

So, what I'm proposing is that we use "know" and "knowledge" more laxly, because this stringent definition doesn't allow it to be used very often in normal speak.