Re: Extending my question. Was: The relational model and relational

In message <7Ik5a.164$8e.17186852_at_mantis.golden.net>, Bob Badour <bbadour_at_golden.net> writes

>> You and Date insist that cardinality can only be determined by counting,
>> which
>> requires distinguishability. I have a scale that allows me to determine
>> the cardinality
>> of a multiset of tuna cans by their collective weight.
>
>If you cannot identify the cans of tuna, how do you place them on the scale?

You pick one of them up (any one will do) and put it on the scale. You don't need to identify which can you are choosing (given the assumption that all of the cans have the same weight).

>And before you can calculate a count from a weight, you must first count
>identifiable cans then weigh them.

No, you have to count cans. You do not have to count identifiable cans.

-- 
Bernard Peek
bap_at_shrdlu.com
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