Re: Objects and Relations

On Feb 16, 2:30 pm, "Keith H Duggar" <dug..._at_alum.mit.edu> wrote:
> David BL wrote:
> > JOG wrote:
> > > Yes exactly, if you so wished. Or a surrogate could
> > > represent its path over time, whatever gets the job
> > > done.
>
> > So you're saying a surrogate id can represent an
> > "untrackable attribute", standing for the complete world
> > line of a particle through space and time, without
> > actually acknowledging that the particle exists!
>
> As I pointed out before, 'exists' is a semantic vacuum. Your
> final phrase is equivalent to "without actually acknowledging
> that the particle is ... !" The '...' is empty, meaningless
> filler just as "exists". Until that void is replaced with
> facts, it remains meaningless.
>
> > How do you explain the surrogate id in the relation
>
> > Position(*id,*t,x,y,z)
>
> > used to record the world lines of multiple particles that
> > are otherwise indistinguishable?
>
> You are so close; so very close to an epiphany. If they are
> otherwise indistinguishable then don't distinguish them!

I have no problem with that, except that if we drop the id attribute we can't for example, easily display connected world lines on a spacetime  diagram.

> Not
> knowing the context I can't say for sure but it seems either
> (t x y z) or (t x y z count) would be more appropriate for
> configuration and ((t x y z) (t x y z)) for transitions.

What is count?

I can see that ((t x y z) (t x y z)) allows for the connectivity of space-time points of a world line to be established. Interesting!

> > > > I am struggling with your assertion that relations
> > > > only are about roles and values, not entities.
>
> > > A relation is a subset of the cross-product of n
> > > domains. Those domains do not contain 'entities' they
> > > contain values. I hope that clarifies it.
>
> > Far from it. Let me explain my pov, by describing what
> > various terms mean to me. Perhaps you may see something I
> > have wrong. If that is the case I would appreciate
> > something more specific and useful than merely "nonsense"
> > (as Bob would typically say).
>
> > The word "exists" appears a lot in mathematics. For
> > example consider
>
> > P = there exists nonzero integers x,y,z
> > such that x^2 + y^2 = z^2
>
> That is a specific, well defined use of the word "exists"
> (quantification) attached to a predicate (x^2 + y^2 = z^2).
> And the predicate is crucial. In contradistinction, informal
> use of "exists" (certainly as you have used it attached to
> "entity") map to meaningless statements such as:
>
> P = there exists x y z ...
>
> that amount to nothing until ... is filled in.

Good point. I like that.

> > Generally speaking mathematicians don't waste time arguing
> > about whether the integers exist. Instead they assume it
>
> No they don't. They assume integer values satisfy properties
> or axioms, not that they "exist" in your metaphysical sense.
>
> [summarize hyperbolic metaphysical rant]
>
> > ... tenable ... No! ... Platonic view ... admit it ...
> > fuzzy ... mockery ... do you really want ... pretending
> > ... you'll get stuck ... infinite regress ... you'r own
> > sentences ... are not allowed ... No! ... Platonic realm
> > ... forces us ... to agree ... to have any hope ...
> > but it is *you*

Yes it is metaphysical rant. Received on Fri Feb 16 2007 - 08:34:03 CET