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Re: [uom-ontology-std] A measure (or magnitude) is not a quantity

To: <uom-ontology-std@xxxxxxxxxxxxxxxx>
From: "Rijgersberg, Hajo" <Hajo.Rijgersberg@xxxxxx>
Date: Thu, 24 Sep 2009 16:47:00 +0200
Message-id: <81FED4D03D7F594E8CB22C6F42E6DA85015F9CE9@xxxxxxxxxxxxxxxxxxx>
>>>> Please allow me to make a remark about measures (or mangnitudes) and
>>>> quantities. I have seen several times that a measure (or magnitude),
>>>> such as "3 kg", is regarded as a quantity. However, a quantity is a
>>>> metrological aspect of a phenomenon, such as "the mass of my table"
>>>> ("mass" is a metrological aspect
>>>
>>> Whoa. Mass is an 'aspect'? Surely not. Mass is, after all, one of the
>>> fundamental physical quantities. The particular mass that an object has
>>> might be considered to be a property of that thing, but mass *itself* is
>>> surely something beyond that. And in any case, why do you consider 
>>> it to be 'metrological'? (Or does this simply mean, capable of being
>>> measured?)
>>
>> Yes, mass is one of the fundamental physical quantities. But is also a
>> metrological property of an object or an event at the same time. (With
>> "aspect", I meant "property".)
>
> Then please use the normal word, to avoid confusion.    (01)

That's a good idea. I'll do that.    (02)


> BTW, in idiomatic English I think it would be more natural to say that an 
>object *has* a 
> mass, rather than using 'mass' directly as a property.    (03)

"has" is very general property. If this is specified to "hasMass", one in fact 
arrives at "mass".    (04)


>> What do you mean with the *particular* mass of an object or event? Do
>> you mean the *value* that the quantity may have?
> 
> I meant the particular mass, considered as a unique entity; if "the 
> mass of my table" is considered to be a referring phrase, then it is 
> whatever that phrase refers to. If mass is a property, then this would 
> be a trope.
> 
> We now have aspects, properties, quantities and values. The vocabulary is 
>becoming confusing.     (05)

We shouldn't use the word "aspect", as I agree with you. I regret to have used 
this word.    (06)


> If my table weighs 3 kg, then massOf is a 
> property which relates the table to something. I call that thing a 
> particular mass, in this case the mass 3kg.    (07)

Then you call a measure/magnitude a particular mass. To my opinion that is 
confusing. But if it is only a name thing I can live with that. Problem: will 
other people understand?    (08)


> It in turn is related by another relation (or maybe a function) called 
>'kilograms' to the 
> (pure) number 3. So, in your terminology, is the 'value' here 3kg, or 
> 3? And what is the 'quantity'?    (09)

I can't imagine kilogram as a function. I think the value is "3 kg", which is a 
measure/magnitude. And the quantity is "mass of my table".    (010)


>> (It is important to distinguish the quantity from the measure/magnitude (the 
>value) that 
>> it may have.)
> 
> By 'quantity' here, do you mean the aspect/property? Or are values 
> distinct from properties?    (011)

Regardless of properties, a quantity is a concept like "the mass of my table", 
a reference to a metrological property of my object/event. A value, here, can 
be a measure/magnitude, such as "3 kg". How we should model all this, what's a 
class, what's a property is in fact a next step.    (012)


>> "Metrological" is an important property of the kind of concepts that 
>> we
>> are talking about. Indeed, it means capable of being measured or
>> something like that.
> 
> Can you give an example of a non-metrological property?    (013)

If you mean a non-metrological *concept*: something that can be observed.  What 
about the color of an object?    (014)


>>> A table is a phenomenon? What on earth does that mean? Surely a table
>>> is an object, if indeed one believes that there are objects at all.
>>> But to not believe that is quite a stretch for most, er, ontologies.
>>
>> Is this perhaps the kind of philosophy that we should not be doing?
> 
> This is not philosophy, just me trying to understand your intended 
> meaning.    (015)

OK.    (016)


>>>> There can exist a statement about the mass of my table, such as
>>>> "the mass of my table = 3 kg".
>>>
>>> That the *statement* can exist is proved by the fact that you just
>>> wrote it. Do you mean to say, that such a statement is incorrectly
>>> phrased, or something like that?
>>
>> I only meant to say that with relation to a quantity a statement can 
>> be formulated.
> 
> Um... OK, but that is so obvious that it does not need saying. I was 
> wondering if there was some other, deeper, meaning which you meant to 
> imply.    (017)

I was trying to emphasize that there are different ways to formulate a 
statement about a quantity. One way is fomulating a statement like "the mass of 
my table =  3 kg", and another way is specifying the particular mass's value. 
Like below.    (018)


>>>> What we also often see is that a measure (or magnitude) is the value
>>>> of a quanitty, such as "the mass of my table" --->> value---> "3 kg".
>>>
>>> So, which is the proper formulation, on your view? (I am genuinely
>>> confused at this point.)
>>
>> I think both are proper formulations. Both are often used in practice.
>
> If they are both correct, then it follows that the relation called 
> 'value' is reflexive. Is this really what  people who use the second 
> formulation intend?    (019)

You mean every element is related to itself? I wouldn't think so; "the mass of 
my table" is a quantity, and "3 kg" is a measure/magnitude. It is possible that 
a quantity has another quantity as its value, but not necessarily (namely, a 
measure/magnitude).    (020)


> Pat    (021)

Hajo    (022)



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