>Dear Chris, Matthew, John, Adrian, and Florian,
>I thought that all those issues had been settled decades ago (01)
They have been being discussed that long, but they never get settled. (02)
>CP> Would there be a single object (John), who is an instance
> > of both employee and person, in your scheme of things?
> > I think you need this to get your sub-type relation.
>CP> This enables me to allocate responsibility to the employee
> > but not to the person.
>We don't have two individuals here. There is only one.
>If I'm assigned a task as an employee, it's my task, not
>the task of some virtual employee.
>MW> This is also what we now do with a 4-dimensionalist
> > approach. However, it is this approach that also demonstrates,
> > as I explained to Duane that employee is not a subtype of
> > person, taking person as the person-for-the-whole-of-their-life.
>Subtype has a very clear and simple definition: X < Y
>means that every instance of X is an instance of Y. (03)
I would prefer to say that it implies this, but subtype is actually
somewhat stronger. Not every occassion of one category being included
in another need be viewed as a subtyping. BTW, this 'intensional'
perspective gives more efficient reasoning, as well as being more
>This is true in a 3-D version and in a 4-D version. When a
>person stops being an employee, there is no employee. But
>as long as a person is an employee, that employee is one
>and the same individual as that person. (05)
That doesn't make sense in a 4-d framework, or else its false. You
are using the 3-d (continuant, temporal) notion of 'same' here (shown
by the weasel phrase "as long as"). In the 4-d way of talking,
identity is timeless and holds between temporally extended entities.
A temporal part of an instance is not usually an instance. (06)
>MW> Let us look at a couple of possibilities here:
>This definition covers every case. It is true in a 3-D
>version and in a 4-D version. It implies that the entire
>spatiotemporal extent of Employee is included in the
>spatiotemporal extent of Person. (07)
Not unless you conflate class membership with temporal parthood. I
think Matthew is keeping these ideas separate. (08)
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