New definition of mass

Issues with quantifying (measuring) mass do not mean that nobody knows what mass is.

You might have trouble measuring the length of a bacterium, but that doesn't mean you don't know what length is.

 

arfa brane:

Useful quantities in physics typically have operational definitions. An operational definition says "To measure the X of a thing, follow these steps: 1. blah blah blah; 2. blah blah blah; etc." Note that following the "recipe" is what defines the quantity X; this is different from having some abstract definition of X and then trying to work out ways to determine it after the definition is established.

In the case of mass, one operational definition might look something like this:
1. Apply a known force F to an object.
2. Measure the resulting acceleration of the object.
3. The ratio F/a is the mass, m, of the object.

In light of that...

Yes, I can give you operational definitions of both length and mass. Therefore, I know what they are.

Well, you're wrong again. Or still wrong, as it may be.

You did a bad job of trying to predict what I would say. Maybe give that up. You might learn more.

Er... numbers are numerical. Aren't they?

If you tell me you're 5 feet tall, I'd say that the "5" in there is a number. Wouldn't you?

A simple rule of thumb is: look for the numbers. There is no "5" in the colour "blue", for instance, but there is a "5" in "5 feet tall". It's not very hard to spot numbers.

You think it's flawed? Tell me how its flawed, and what your superior solution is to this hard problem of numbers that you've discovered.

 

Then, can I assume you won't be using that term in future?

You literally wrote "Of course, you will say, everyone knows what distance is. It's that thing between two separate points, eh?"

I'd say my "accusation" is clearly supported by your words. Don't you agree?

That you follow up with an attempted insult is also something I have come to expect from you. You can't help yourself.

"feet", in this context, is a unit of measure.

I have already accepted that many physical quantities have units.

It remains the case that you can't put "5 feet" in a bottle. You can't see "5 feet". You can't eat "5 feet". You can't smell "5 feet". "5 feet" can't talk to you or make you a cup of coffee. "5 feet" is just a number and a unit. It is, of course, typically associated with measuring a distance or length. That has never been a matter of disagreement.

When will you work out that mere assertion is not an argument? What you need, if you're serious, is some kind of reason why you think "5 feet" is something other than a number and a unit. Otherwise, you're just giving us your opinion for the nth time, and that's not worth any more than it was the first time.

Masses and charges don't influence each other.

Two objects can attract each other gravitationally, or electrically if you like. But you can't produce two masses that will attract one another. You can't bottle mass. Mass won't make your coffee.

 

Unevidenced assertion, as usual.

How so? Where? What did Feynman say that's different from what I said? Quotes, please.

Units, just like numbers, are concepts. You can't bottle units. There's no such thing as a bottle of kilograms, or a bottle of Joules.

Sheesh. How hard is this for you? Seriously. Are you really unable to distinguish a concept from a physical object? Or is this just some kind of time-wasting game you're playing?

No bottle of time. Right. And therefore... ?

 

arfa brane:

Are you unable to acknowledge the distinction between a concept or property and a physical object to which that concept or property applies, or just unwilling to acknowledge the distinction?

I notice that you keep skipping over the core of our disagreement, to talk instead about irrelevancies. Mass and length are properties of things, not things in and of themselves. Mass is not a "thing" that does anything of its own accord, or which can cause anything to happen. Mass is a concept in your head. A tennis ball is a thing that you can put in a bottle. We can associate a concept (a number), called mass, with a thing called a tennis ball. But the mass of the tennis ball is not the tennis ball. The tennis ball can fall on your head. Its mass cannot.

Do you disagree with any of this? Do you have any thoughts at all on any of this? Are you able to bring yourself to think about any of this? Are you able to express an opinion that is on topic on any of this?

Now, we can also deal with the irrelevancies, but you should really try to engage with the core rather than insisting on messing about at the periphery all the time.

Not necessarily. Does it matter?

Okay.

Okay.

So what?

Units are signposts, pointing us towards the kind of thing that the number is representing. 5 kilograms tells us that we're dealing with mass. 5 kilometres tells us that we're dealing with distance or length. Also, units always have a reference. To talk meaningfully about 5 kilograms, we have to already have a well-defined concept of what 1 kilogram is. For 5 kilometres to be useful, we need to know what 1 metre is.

Units are concepts. 1 metre, for instance, is defined to be the distance travelled by light in a vacuum in 1/299792458 seconds. That is a conceptual definition. You can't bottle 1 metre. You can't open a jar of metres or have 1 metre hit fall on your head.

Do you accept that objects can attract each other gravitationally or electrically? If you do not, then we have a lot more issues to work through with you than I thought.

No. I have not contradicted myself. Nor have you been coherent enough to even attempt to point out a contradiction.

Charges don't influence each other. How can a number influence another number? Can concepts collide? Can a concept hit you on the head?

You're failing to engage. Try harder. Concentrate on the core issue, which is your confusion between concepts and objects. The two are not the same thing. Once you understand that, everything might become clearer for you.

By "charge" we usually mean electrical charge, and that is what I assumed you meant. I am happy to accept that mass is a kind of charge, that relates to gravity rather than electomagnetism, if you like. It's a nit picky irrelevance to your core confusion.

 

A distance is not an object. Do you agree, or not?

I'm sorry to see you struggling so mightily with what I think is a very simple concept.

Here's what I wrote: "Units are signposts, pointing us towards the kind of thing that the number is representing. 5 kilograms tells us that we're dealing with mass. 5 kilometres tells us that we're dealing with distance or length."

I'm happy to answers specific questions. Tell me what you can't fathom in that statement of mine and perhaps I can put it in simpler language you can understand.

I thought we agreed that you would stop using the term "physically real", because you're unable to define what that means.

If you think you can define it, then tell me what it means to you for a speed to be "physically real"? What is required for a speed to become physically real, as opposed to being conceptual? What is required for an electric field to become physically real, as opposed to conceptual?

Once again, I notice that you completely skipped over the concept/object distinction that I pointed out at the start of my previous post. Why is that? Mental block? Blind spot? Too hard for you?

Tell me what "physically real" means, then I'll try to give you an answer.

They aren't objects. Making a measurement is a process. The result of a quantitative measurement is a number. Numbers are conceptual. (Although, maybe "physically real" includes numbers, for you, which might make numbers "physically real" as well. I can't tell what you think unless you tell me.)