Re: [ontolog-forum] Thing and Class

[Pat Hayes <phayes@xxxxxxx>]

At 8:48 AM -0400 9/9/08, John F. Sowa wrote:

> Dear Matthew,
>
> Whether you have a 3D or a 4D perspective, change still exists,
> and the distinction between extension and intension is still
> significant.

Of course. But the key point is that to assert existence in the 4d framework an assertion itself is not temporal. Assertions stand outside time and speak about it, rather than being embedded in it and having to speak about other times indirectly, for example by using tenses. Moreover, it frees one from the confusion that relates intensionality to existence over time.

> JFS>> But even for a fixed design, the set changes with every
> instance
>  >> that rolls off the assembly line.
>
> [MW] Only if you take a 3D perspective which sees what exists as
> What exists NOW.
>
> In any perspective, you must be able to plan for the future, talk
> about what exists NOW, or what exists in some hypothetical time
> or place that might never exist anywhere in the 4D
> universe.

Not true. There is no 'now' in a 4-d universe.

> You must also be able to talk about hypotheticals that could have
> existed in the past when you're carrying out a forensic
> investigation
> about how some situation at some point in time and place happened
> to evolve out of some other situation at some other time and
> place.

All of which is a lot easier in a 4-d framework.

> JFS>> You can't use extensional terms such as 'set' and 'class',
> which
>  >> change with every instance that rolls off the assembly
> line.
>  >> It's essential to use intensional terms, such as
> 'category' or
>  >> 'type'.  Since 'type' takes one syllable instead
> of four, that
>  >> is a good choice.
>
> [MW] But you can if you are a 4-dimensionalist.
>
> A 4D world view does not preclude change.

Of course not, but it does enable one to distinguish between a description of change, and a changing description. JFS seems to be embedded in a framework which conflates these so badly that the difference is invisible, which is MW's point.

>  The fundamental laws of
> physics are stated as partial differential equations that vary
> in the spatial coordinates and the time coordinate.
>
> So you can and must be able to think, talk, and plan for change
> in our actual universe.  You must also be able to talk about
> the
> hypothetical aspects of the universe that might or might not exist
> in any region of the actual universe.
>
> Bottom line:  The distinction between extensions and intensions
> is
> independent of any coordinate system or point of view.  It is
> fundamental to any theory, language, or logic for
> ontology.

Bottom line: don't get intension/extension confused with temporal criteria of identity, and don't get either of them confused with set/individual. JFAS thinks that sets change, which is wrong. Sets are like numbers, they are Platonic individuals. To lose this point is to become hopelessly confused. If we speak of a set of widgets, and then a new widget is made, the SET has not changed. There are two sets, one having one more element than the other. Sets aren't the kind of thing that can possibly change.

Pat

> John
>
>
>  
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