Re: Counting propositions

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> > > > > > > > > Ok. But why there is a need to know this number ?
> > > > > > > > > It is like saying "today I made 100 affirmations".
> > > > > > > >
> > > > > > > > Have you never wanted to know how many of something you had?
> Can
> you
> > > > > > > > not envisage a large business wanting to know, for example,
> how
> many
> > > > > > > > employees it has?
> > > > > > >
> > > > > > > Employees yes. Propositions no.
> > > > > >
> > > > > > Very droll ;-)
> > > > > >
> > > > > > But the fact is that from the N propositions we have that say "We
> have
> > > > > > an employee named xxx with salary yyy ...", we can deduce the
> useful
> > > > > > fact that we have N employees - simply by counting the
> propositions.
> > > > >
> > > > > What made you so sure.
> > > >
> > > > What makes you so unsure? Are you making some kind of philosophical
> > > > point that I'm not getting?
> > >
> > > Well, because you don't directly count employees, but you count
> propositions
> > > about employees instead, it is a legitimate question to ask if the
> result is
> > > accurate and why.
> > >
> > > Other reasons:
> > > - the database may contain propositions about past, current and future
> > > employees
> > > - the database may contain propositions about employees in different
> > > relations (or relvars)
> > > - it might be hard to distinguish propositions about employees from
> other
> > > propositons in the database
> >
> > Well, you ceertainly have to know what the propositions mean before
> > you can get a meaningful answer by counting them. If the propositions
> > include past and future employees then you should ensure that you only
> > count the propositions about current employees by adding the
> > appropriate WHERE clause.
> >
> > It shouldn't be at all hard to distinguish propositions about
> > employess from other propositions in the database, because a
> > relation/table must only hold propositions of one type.
>
> So you say that the employees are in *one-to-one correspondence* with the
> propositions about employees, or something like that and this is the reason
> you can count propositions to determine the number of employees ?

I do, though I sense I may be walking into a trap ...

I guess the term "external predicate" comes in here, i.e. the knowledge that these propositions each assert the employment of 1 employee is implicit. From that, one can deduce that the existence of N propositions implies the existence of N employees. Whether these "propositions" are stored in a DBMS or written down in biro in a spiral-bound notebook, it is obvious that one can count the (known) employees by counting the number of entries (provided we disallow duplicates). Received on Thu Jun 17 2004 - 16:09:30 CEST