Can we know that something doesn't exist?

@kennethamy,

kennethamy;137363 wrote:

It doesn't. It just shows the difference between laws of nature and regularities.

Then your premise is unsupported. You haven't shown that anything is physically impossible.

@Night Ripper,

Night Ripper;137366 wrote:

Then your premise is unsupported. You haven't shown that anything is physically impossible.

He has shown how it would be physically impossible - it would violate a law of physics! The fact that you don't believe physical impossibility exists or you're not accepting the term, doesn't mean the premise is unsupported.

@Zetherin,

Zetherin;137368 wrote:

He has shown how it would be physically impossible - it would violate a law of physics! The fact that you don't believe physical impossibility exists or you're not accepting the term, doesn't mean the premise is unsupported.

His conclusion...

Quote:

Therefore, 3. It is physically impossible for water to freeze at 70 degrees.

...rests on an unsupported premise, "it is a law of nature that water does not freeze at a temperature greater then 32 degrees". The truth of that premise is not established.

@Night Ripper,

Night Ripper;137369 wrote:

His conclusion...

...rests on an unsupported premise, "it is a law of nature that water does not freeze at a temperature greater then 32 degrees". The truth of that premise is not established.

You ought to look it up. Any elementary science book will tell you that water freezes at 32 degrees. And will explain why that is true. Hint: it has to do with how the water molecules act when the water is brought down to that temperature. It is not, I assure you, an accident. For example, if the molecules of aluminum were water molecules, they would freeze if brought down to that temperature, too.

By the way, a premise can be unsupported but true, nevertheless. So, the fact (if it is one) that the conclusion rests on an unsupported premise does not mean that the conclusion is not true, nor does it mean it has not been proved to be true.

@kennethamy,

kennethamy;137378 wrote:

You ought to look it up. Any elementary science book will tell you that water freezes at 32 degrees.

The problem is that "water freezes at 32 degrees" is not the same as "water must freeze at 32 degrees" nor does it imply it. The true statement "water freezes at 32 degrees" does not mean that it's "physically impossible for it to freeze at 70 degrees".

@Night Ripper,

Night Ripper;137379 wrote:

The problem is that "water freezes at 32 degrees" is not the same as "water must freeze at 32 degrees" nor does it imply it.

Who ever said it does? You don't understand that that was never said. I told you this.

@Zetherin,

Zetherin;137380 wrote:

Who ever said it does?

kennethamy said this:

Quote:

Therefore, 3. It is physically impossible for water to freeze at 70 degrees.

@Night Ripper,

Night Ripper;137382 wrote:

kennethamy said this:

That's not what that sentence means. I have explained what it means countless times. Man, you really must just be ignoring my posts.

@Zetherin,

Zetherin;137383 wrote:

That's not what that sentence means. I have explained what it means countless times. Man, you really must just be ignoring my posts.

Are you telling me that "physically impossible" doesn't mean "can't happen"? Maybe you should let kennethamy argue for himself because you aren't making much sense to me.

@Night Ripper,

Night Ripper;137384 wrote:

Are you telling me that "physically impossible" doesn't mean "can't happen"? Maybe you should let kennethamy argue for himself because you aren't making much sense to me.

I am not arguing for kennethamy. I am arguing for my own sanity at this point. I can't understand how you don't understand this. A violation of a law of physics is what a physical impossibility is. A violation of a law of physics is that water freezes at 70 degrees. Therefore, water freezing at 70 degrees is a physical impossibility! What about that can you just not seem to grasp?!

I have repeated this countless times throughout the day, as many ways as I could. There is something you're not understanding, but I just can't put my finger on it.

@Zetherin,

Zetherin;137385 wrote:

A violation of a law of physics is what a physical impossibility is.

In that case, "impossibility" is not an ontological claim, because laws of physics are not exact descriptions of reality.

Zetherin;137385 wrote:

A violation of a law of physics is that water freezes at 70 degrees.

I have asked you to specify the law violated. The freezing point of water, at STP, is an empirical matter, as far as I know.

@Zetherin,

Zetherin;137385 wrote:

A violation of a law of physics is what a physical impossibility is. A violation of a law of physics is that water freezes at 70 degrees. Therefore, water freezing at 70 degrees is a physical impossibility! What about that can you just not seem to grasp?!

I can't grasp the same unsupported premise in your reworded version -> "A violation of a law of physics is that water freezes at 70 degrees."

Where's the argument for this? The same criticism applies. You have added nothing.

@Night Ripper,

Night Ripper;137379 wrote:

The problem is that "water freezes at 32 degrees" is not the same as "water must freeze at 32 degrees" nor does it imply it. The true statement "water freezes at 32 degrees" does not mean that it's "physically impossible for it to freeze at 70 degrees".

Yes, I agree. But what has that to do with it?

Suppose a piece of gold were water, then that piece of gold would freeze at 32. Now, gold does not freeze at 32, but if it were water it would. Why would we know that unless it is physically necessary for gold (and any other substance) to to freeze at 32 if it were water? After all, if that piece of gold happened to be copper, it would not freeze at 32. So why would it freeze at 32 if it were water? Is it an accident?

@kennethamy,

kennethamy;137400 wrote:

Is it an accident?

Sure, why couldn't it be an accident?

@Night Ripper,

Night Ripper;137403 wrote:

Sure, why couldn't it be an accident?

Because we know the reason why it would happen...

@Zetherin,

Zetherin;137404 wrote:

Because we know the reason why it would happen...

Can you elaborate? What's your entire argument that anything at all is physically impossible, without breaking it up into multiple posts?

@Night Ripper,

Night Ripper;137405 wrote:

Can you elaborate? What's your entire argument that anything at all is physically impossible, without breaking it up into multiple posts?

See, you've been stringing me along the entire time. It isn't that you don't understand the argument or what physical impossibility means, it is that you want proof that laws of physics even exist. Is that correct? If so, this is where I stop.

@hue-man,

This is getting quite silly. The only support given for physical impossibility has been Hempel's theory of explanation or vague appeals to either laws of nature or laws of physics. I have given counter examples and a general refutation of the deductive nomological theory of possibility, laws of physics obviously dont decide what's possible and laws of nature are quite contentious. I conclude that physical possibility is a folk notion and needs stipulative definition if it's appealed to.

@ughaibu,

ughaibu;137409 wrote:

This is getting quite silly. The only support given for physical impossibility has been Hempel's theory of explanation or vague appeals to either laws of nature or laws of physics. I have given counter examples and a general refutation of the deductive nomological theory of possibility, laws of physics obviously dont decide what's possible and laws of nature are quite contentious. I conclude that physical possibility is a folk notion and needs stipulative definition if it's appealed to.

Even if that's so, you should understand the argument. It seemed as though the both of you didn't. If you do, and your main concern is that laws of physics do not exist, then that is another matter entirely. Just know there is a term "physical impossibility" and it was correctly used here.

Thanks,

Zeth

@Zetherin,

Zetherin;137410 wrote:

Even if that's so, you should understand the argument. It seemed as though the both of you didn't. If you do, and your main concern is that laws of physics do not exist, then that is another matter entirely. Just know there is a term "physical impossibility" and it was correctly used here.

Of course I understood the argument! I've replied to it here:

ughaibu;137250 wrote:

It fails to do what was requested, and that is to distinguish what does happen from what can happen. Your argument amounts to an assertion that what doesn't happen is impossible.

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.

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Can we know that something doesn't exist?

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