Can we know that something doesn't exist?

@hue-man,

hue-man;131923 wrote:

Can we ever be positively (not absolutely) certain that any particular thing doesn't exist?

Exists as what exactly? And "thing" is very vague. A physical tangible or a conceptual arrangement? If you say unicorns do not exist, they obviously exist as an idea or as some process of reasoning. Think of Plato's Theory of Forms - the world of ideas. Do you agree ideas have "existence"? You do not necessarily have to be a dualist to believe in such, just recognise an ontological difference between what "existence" really implies.

- Minimal.

@ughaibu,

ughaibu;137412 wrote:

Of course I understood the argument! I've replied to it here:
Basically, it's an assertion, that's all. If your concern is about everyday usage, then an argument wasn't needed, and these several pages have been time wasted. A simple statement that you're supporting physical possibility as an informal everyday concept as defined by standard dictionaries, would've been the end of it. That has certainly not been Kennethamy's approach.
And it is completely obvious that laws of physics exist, because laws of physics are a specific subset of statements made by physicists and nothing more.

Well, what is the thing you seek justification for, or do you think is unsupported? You state laws of physics do exist here. And, what has been spoken about here, as far as I understood it, was that a violation of a law of physics would occur if water froze at a higher temperature.

So, you're right, what have we been arguing over here?

@Zetherin,

Zetherin;137416 wrote:

what has been spoken about here, as far as I understood it, was that a violation of a law of physics would occur if water froze at a higher temperature.

1) in order for a theory to be scientific, that theory must make predictions that might fail, and if the prediction fails, then the theory is false. It is implicit in the nature of scientific theories that they can be empirically refuted. So, it is not the case that a contravention of any scientific theory is impossible, in anything other than an informal folk sense.
2) for the third time; what law of physics dictates that water freeze at 0c? I doubt very much that there is such a law, as the freezing points of liquids are not only temperature dependent.

@ughaibu,

ughaibu;137419 wrote:

1) in order for a theory to be scientific, that theory must make predictions that might fail, and if the prediction fails, then the theory is false. It is implicit in the nature of scientific theories that they can be empirically refuted. So, it is not the case that a contravention of any scientific theory is impossible, in anything other than an informal folk sense.

Actually, I think this point needs clarification. Scientific theory:
"a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge..."

There would not be a scientific theory if there was no substantiation of such a claim. "Theory" is not just a tentative proposition but a well-substantiated conclusion which would be shown to be verifiable, ergo testable. Theories can be overthrown but one test showing contrary would probably not be enough - you would have to create a body or systemic arrangement of data to supersede the previous theory's conclusion. You seem to make theory sound more like a hypothesis.

- Minimal.

@Minimal,

Minimal;137422 wrote:

Theories can be overthrown but one test showing contrary would probably not be enough - you would have to create a body or systemic arrangement of data to supersede the previous theory's conclusion

A theory can be refuted without the proposal of an alternative theory. If a theory is false, that's it, it doesn't remain true until something better comes along. In any case, the point relevant to the present discussion remains, a theory is not scientific if it is impossible for an observation to falsify that theory. Therefore, it is not the case that an event which contravenes a law of science, at least under the deductive nomological theory, is impossible.

@ughaibu,

ughaibu;137423 wrote:

A theory can be refuted without the proposal of an alternative theory.

You can only prove a theory false by presenting different implications of the data in relation to the conclusion - you would have to provide substantiation. You would either provide a breakthrough in how data is interpreted or show a different conclusion that grows out of data - or supersede the theory that provides a better explanation of the majority of data. You cannot go, "This is false because I said so." That is just not how science works. By refuting the theory you would have to either alter how the majority view the data or provide a breakthrough that leads into a new theory that explains the data with greater consistency - with empirical substantiation of course.

- Minimal.

@Minimal,

Minimal;137428 wrote:

You can only prove a theory false by presenting different implications of the data in relation to the conclusion - you would have to provide substantiation. You would either provide a breakthrough in how data is interpreted or show a different conclusion that grows out of data - or supersede the theory that provides a better explanation of the majority of data.

If a theory predicts that given a set of conditions a certain phenomenon will be observed, and experimental observations are of a different phenomenon, then that theory fails. It doesn't need to be replaced by a new theory. And if a theory makes no predictions of observations that support that theory in contradistinction to observations that would be inconsistent with that theory, then that theory is not scientific. The argument following from this is straight forward:
1) scientific theories make potentially falsifying observational predictions
2) laws of science are the premises of logical arguments which constitute scientific theories
3) laws of science can be refuted by observation
4) therefore it is not impossible for an event to contravene a law of science.

@ughaibu,

ughaibu;137432 wrote:

If a theory predicts that given a set of conditions a certain phenomenon will be observed, and experimental observations are of a different phenomenon, then that theory fails. It doesn't need to be replaced by a new theory. And if a theory makes no predictions of observations that support that theory in contradistinction to observations that would be inconsistent with that theory, then that theory is not scientific. The argument following from this is straight forward:
1) scientific theories make potentially falsifying observational predictions
2) laws of science are the premises of logical arguments which constitute scientific theories
3) laws of science can be refuted by observation
4) therefore it is not impossible for an event to contravene a law of science.

A theory is a well tested body of information, not a hypothesis. The body of information creates general principles that are the most consistent. And I never stated you necessarily needed a new theory. I stated you could question the implications of the conclusion drawn based on the data and principles obtain from such - refinement and further substantiation of the new interpretation of previous data and the conclusion/s drawn being false. You would need to provide reasoning as to why this new finding contradicts the entire body of data collected. You need to show why the experimental conditions may have manifested a different result than previously expected and in fact check if such outliers have been reported in previous studies. Refutation is not just stating something is false by demonstrating the flaws. A theory is not sacred it is just where the majority of data leads us. By refuting you would either refine the previous theory or you would find a systemic way of having a more consistent picture of the majority of data. It is even possible your experimental findings would called outliers and the experimental conduction altered results. Would you throw out a functional theory if one study out of a thousand showed contrary? I think you would call it an outlier ;-)

I am not trying to debate with you here. Your original description read more like a hypothesis than a theory to me, that is all.

- Minimal.

@Zetherin,

Zetherin;137331 wrote:

You must have some concept of a square circle to know it cannot be instantiated. Otherwise, what do you think cannot be instantiated?

You must only have a concept of a square and a concept of a circle to know that a combination of the two concepts cannot be instantiated.

Samm

@Minimal,

Minimal;137435 wrote:

I am not trying to debate with you here. Your original description read more like a hypothesis than a theory to me, that is all.

Okay, but the statement that you responded to was part of a dialogue, and for the purposes of that dialogue I only needed to mention the feature of scientific theories relevant to the argument.

@ughaibu,

ughaibu;137438 wrote:

Okay, but the statement that you responded to was part of a dialogue, and for the purposes of that dialogue I only needed to mention the feature of scientific theories relevant to the argument.

My apologies for the interjection in that dialogue - I was actually just trying to clarify a point for potential readers who may question the definition. I have nothing to say with regards to your argument in that dialogue, just wanted to clarify a point I thought was ambiguous :-)

- Minimal.

@Minimal,

Minimal;137439 wrote:

My apologies for the interjection in that dialogue - I was actually just trying to clarify a point for potential readers who may question the definition. I have nothing to say with regards to your argument in that dialogue, just wanted to clarify a point I thought was ambiguous.

Well, that's fair enough and no need for an apology.

@ughaibu,

Maybe it's like this:

Imagine that a group makes the claim that the Second Coming of Christ is happening and they point to an event where the Holy Spirit descended on a church and the holy water froze. It was 70 degrees Farenheit at 1 atmosphere of pressure in the church (they have a temperature/barometer that continuously records)

Imagine this happens at a time when large numbers of really intelligent people are so in love with the notion of the Coming, that they trip over themselves to join in and eventually they're stating from their scholarliness that the Coming is scientifically verified.

This is when we all drop whatever angst we might have had about analytical philosophy and thank our luck that we have it. We don't have to start from scratch to sort out how to approach the question of what we really know.

I'm saying it changes things when we're confronted with the hardcore passion and poetry of human experience. Passion talks. Analysis doesn't say anything... it helps us navigate through what we've already said.

@Night Ripper,

Night Ripper;137403 wrote:

Sure, why couldn't it be an accident?

If what looked like molten metal suddenly froze at 32, and on analysis turned out to be H20, then after we got over our shock wouldn't we say, "well, no wonder it froze. It is water"? How would we explain it otherwise?

@kennethamy,

kennethamy;137493 wrote:

If what looked like molten metal suddenly froze at 32, and on analysis turned out to be H20, then after we got over our shock wouldn't we say, "well, no wonder it froze. It is water"? How would we explain it otherwise?

If you're noticing that we have assumptions, I agree; we do.

If something that looked like water suddenly froze at 32 F, and it turned out to be metal, would we say: "Bow your heads, my friends... we've seen a miracle." Or would we say "Hmmm.... It appears that our assumptions were wrong. I think there might have been something we overlooked!"

@hue-man,

ughaibu wrote:

In order for a theory to be scientific, that theory must make predictions that might fail, and if the prediction fails, then the theory is false. It is implicit in the nature of scientific theories that they can be empirically refuted. So, it is not the case that a contravention of any scientific theory is impossible, in anything other than an informal folk sense.

If you refer to the meaning of the term, like I've suggested, you would know that that isn't what is being purported. Of course there is no absolute certainty, as humans are fallible.

Quote:

2) for the third time; what law of physics dictates that water freeze at 0c? I doubt very much that there is such a law, as the freezing points of liquids are not only temperature dependent.

Refer to the example found in the dictionary, "It is a physical impossibility that man can fly like a bird". What exact law do you think this would violate? I don't think there is a law named for this specific thing, but the point is that it would go against our understanding of the physical world, as humans cannot fly. It would violate a law of nature as we know it because of the things in the description here. We call it a law because it is a scientific generalization of empirical oberservation. No one is claiming they cannot be wrong!

I have clarified what the term means. You and others are ignoring it, still believing that when we say physical impossibility we mean logical impossibility. But no one has ever stated this.

@Zetherin,

Zetherin;137503 wrote:

We call it a law because it is a scientific generalization of empirical oberservation. No one is claiming they cannot be wrong!

So you're agreeing that we can't know that something doesn't exist.

@Arjuna,

Arjuna;137511 wrote:

So you're agreeing that we can't know that something doesn't exist.

No, I didn't say that. We can know that some things do not exist, such as the Loch Ness monster. Why do you think I said we can't?

I am merely making the point that we are fallible. But our fallibility does not mean we can't know that things don't exist.

But has that to do with what I said?

@Arjuna,

Arjuna;137497 wrote:

If you're noticing that we have assumptions, I agree; we do.

If something that looked like water suddenly froze at 32 F, and it turned out to be metal, would we say: "Bow your heads, my friends... we've seen a miracle." Or would we say "Hmmm.... It appears that our assumptions were wrong. I think there might have been something we overlooked!"

Sorry, what is your point?

---------- Post added 03-08-2010 at 10:39 AM ----------

Arjuna;137511 wrote:

So you're agreeing that we can't know that something doesn't exist.

The fact that we could be wrong doesn't show that we are wrong, and if we are not wrong, then we do know. Therefore that fact that we could be wrong (fallible) does not show we do not know we are right.

@Zetherin,

Zetherin;137503 wrote:

We call it a law because it is a scientific generalization of empirical oberservation. No one is claiming they cannot be wrong!

First of all, you're talking about the laws of science again. Secondly, I've already explained that this has nothing to do with fallibility or skepticism. Regardless of what we can or cannot know, the following statement is either true or false, "nothing ever has or ever will travel faster than the speed of light". I'm already granting for the sake of argument that this statement is true and no mistake has been made. Discussion of fallibility is irrelevant. I'm saying that even with this true statement, it still doesn't imply that going faster than the speed of light is physically impossible.

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Can we know that something doesn't exist?

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