Dear All, (01)
I fear that reaching an understanding of what mass is, is going to be difficult. (02)
There seems to be agreement that there is an object denoted "1.3 kg". In
Ed's synthesis, this is:
- an equivalence class of members of Q1 ("particular quantity");
- a member of Q3 ("magnitude of quantity"). (03)
There are at least two ideas of what the members of "1.3 kg" are, including:
a) the members are mass tropes of different individual quantities of matter;
b) the members are different individual quantities of matter. (04)
To me approach (b) seems simpler. Using this approach, "1.3 kg" is merely a
class of individual quantities of matter which is defined by a single
necessary and sufficient condition - equilibrium with the 1 kg in Paris
using a 1:1.3 ratio balance (or some practical equivalent). (05)
There may be arguments in favour of approach (a). Do we have to choose, or
can we support both? (06)
Similarly for length
--------------------
There is a similar discussion for length (and maybe for all quantities). Two
ideas of what the members of "1.3 m" are, include:
a) the members are length tropes of different individual physical objects;
b) the members are point pairs. (07)
With approach (a), the length of my_table is a member of "1.3 m". With
approach (b), my_point_pair is a member of "1.3 m". There may be a separate
statement that the points in my_point_pair are at opposite ends of my_table. (08)
A question for the ontology experts
-----------------------------------
Can we agree a definition of the object Q3 ("magnitude of quantity"), whilst
at the same time having different understandings of Q1 ("particular quantity")? (09)
Best regards,
David (010)
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David Leal
CAESAR Systems Limited
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