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Re: [ontolog-forum] The Relation Between Logic and Ontology in Metaphysi

To: Pat Hayes <phayes@xxxxxxx>
Cc: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Ingvar Johansson <ingvar.johansson@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sat, 17 Mar 2007 16:32:49 +0100
Message-id: <45FC0A21.2060002@xxxxxxxxxxxxxxxxxxxxxx>
Pat Hayes schrieb:
> So for example, Ingvar Johansson wrote:
> " I happen to think that the dominance of first-order
> predicate logic in the brains of many analytic metaphysiciains mislead
> them into false ontologies. They take away the difference between
> natural kinds and properties (since it is not visible in 'Fa'), and they
> do not allow different modes of existence (since these cannot be seen by
> means of the existential quantifier)."
>
> Well, maybe: but even if this phenomenon (a) does indeed sometimes 
> happen, and (b) really is an error - which of course is open to 
> endless debate, as it has been for the last two millennia -  it is not 
> *impossible* to make these distinctions in FOL. 
I agree, but as long as this has not been done, the risk is there. 
That's all I wanted to say.
> As for "modes of existence", I confess to being one of those with a 
> misled brain, not understanding what is meant by this phrase; but I am 
> sure that if it were to be explained more thoroughly, I could find a 
> way to render it into FOL reasonably briskly.
Here are two examples:
(1) If two philosophers are discussing whether entities of a certain 
kind, F, exist necessarily or contingently, then they are not discussing 
whether what is regarded as F really is of the kind F or not. They are 
discussing in what *way* or *mode* Fs exist.
(2) David Lewis' makes a distinction between endurants and perdurants. 
In my opinion, the natural way to understand this distinction is to 
understand it as a distinction between different *ways* or *modes* of 
spatiotemporal existence; not as a distinction between two 
kinds/properties in the world.    (01)

Let me see your FOL-formalization before I make any further comments 
apart from this one: I have assumed that FOL is understood in such a way 
that existence cannot be part of a predicate. That is, on my assumption, 
you are not allowed to introduce predicates such as 'exists 
necessarily', 'exists contingently', and 'exists by unfolding temporal 
parts'.    (02)

Best wishes,
Ingvar J    (03)


-- 
Ingvar Johansson
IFOMIS, Saarland University
     home site: http://ifomis.org/
     personal home site:
     http://hem.passagen.se/ijohansson/index.html      (04)



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