Dear Ed, (01)
You describe my example as "simply wrong", but I think you misunderstood
what I was attempting to achieve with it, and probably I was insufficiently
clear about this. (02)
I was seeking to illustrate why there are four different objects within the
discussion of Pat's example about the length of a rod. In order to shine
some light on this I created an example OUTSIDE the scope of units of
measure, and without a 3D/4D issue, which is conceptually very simple - a
widget which may or may not be a member of an enumerated set of widgets (a
batch). (03)
I attempted to show that we can define four ANALOGOUS objects for this
example. I did not intend to suggest that "batch of X-1234" is a "particular
quantity", but it is similar to a "particular quantity" in being a type of
object which is not obviously necessary in an ontology. In this way I hope
that the example is relevant. (04)
>> A different example
>> -------------------
>> My initial feeling was in line with Pat's - that there is little need for
>> reified instances of "particular quantity". Worrying about this, I
>> considered an example:
>>
>> Consider the supply of widgets. Widgets are supplied in identified batches
>> containing a finite number of identified widgets. If I have widget with
>> serial number X-1234, I can request an "observation" to determine its source
>> batch. I can define this observation as "determine the batch of widget
>> X-1234". When the observation has been carried out, the answer can be "the
>> batch of X-1234 is B-28". Naively we could say that we have the following
>> objects:
>>
>> - physical object: X-1234
>> - particular quantity: batch of X-1234
>> - magnitude of quantity: the batch that is identified as "B-28"
>> - quantity value: "B-28"
>
>This is simply wrong. I don't believe that B-28 is a quantity value.
>And it is not clear from the description that 'batch of X-1234' is a
>particular quantity. This "batch" is not an amount that can be
>referenced to a unit; it is rather a specific grouping of things.
>
>> The object "batch of X-1234" is a very useful one - it is specified as the
>> objective of an observation, and it can be reported that its value known or
>> unknown. However B-28 is a finite set and X-1234 is a member of it - this is
>> something very simple.
>
>And unrelated to the issue. (05)
Best regards,
David (06)
============================================================
David Leal
CAESAR Systems Limited
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