*****
Some say that an object x may be the same lump of matter as an object y,
even though x is not the same statue as y.  Others say this is incoherent. 
Why does this debate matter?  What can be said for and against the view in
question?

Gibbard, Perry 97+, Loux(?)

Lump x is not the same as statue y because y has form, might have a
different time of creation, and is necessarily a statue where is the lump is
only contingently a statue.  That is, x and y have different (essential,
temporaral, and modal) properties so by Leibniz's law they are discernible
and not identical.

But aren't they identical in some sense?  There are two kinds of identity:
qualitative and numerical.  And certainly they are numerically (and/or
spacially) identical.  They may not be qualitatively identical, but there is
a very important relation between the lump and the statue, namely material
constituency, which makes them identical in a non-qualitative way.  Or, put
another way, the statue is the lump + form.  And this is why it seems right
to say (informally) that the lump and the statue are the same.

(Aside: Maybe what we don't want is strict identity, but sameness (where
sameness only makes sense with respect to a sortal).  x and y are not the
same, but they are the same lump, the same material.  x-qua-lump is the same
as y-qua-lump, but x-qua-lump is not the same as y-qua-statue.  Essences are
funny things; to be a statue is different than to be a lump. Consider two
copies of the same book.  They are the same content-wise but not the same
materially.  Or, book1-qua-text is the same as book2-qua-text, but
book1-qua-matter is not the same as book2-qua-matter.  This kind of thing
crops up all the time in comparision operators in programming.  It seems
that in neither case do we have real identity; we have equivalence.  book1
and book2 are both members of the equivalence class of things which have a
certain text (they are both instances of the class); but book1 and book2 are
not in the same class when classes are sorted by matter.)


*****
Does having a property require existing?

Anthology?

Not if Sherlock Holmes doesn't exist because Sherlock Holmes has the
property of being a detective (among others).  It might be that having a
property requires reference.  Sherlock Holmes names a character that we all
know about.

Do numbers exist?  Not physically.  But 3 has the property of being prime
(or more simply "3 is prime").

What about round squares (impossible objects)?  Do they have the property of
being impossible?


*****
If Wittgenstein could have fathered somebody, does this mean that there is
somebody Wittgenstein could have fathered?  If so, who or what?

Quine, Plantinga(?), Lewis(?)

Not really.  This is one of those silly de re/de dicto problems.  The claim 
"Possibly (Wittgenstein had a son)" does not imply "Wittgenstein had a
possible son".  There's no such physical thing as a possible son anymore
than there are Quine's possible men in the doorway (If there's a possible
man in the doorway, there is a possibly-bald man in the doorway, and a
possibly-dark-haired man, and an infinite number of possible men.)  There
aren't possible sons, there's the possibility of a son.  And possibilities
aren't real things.

Now, Plantinga (actualist) and Lewis (possibilist) offer different accounts
of Kripke's possible world semantics.  According to Plantinga, to say
possibly there is a son is to say there is (in the abstract non-physical
sense of is) a non-actual possible world in which there is a son.  For
Plantinga (if I recall correctly) worlds are just semantic tools; they are
sets of propositions.  So this means there is at least one set of
propositions in which "Wittgenstein has a son" obtains (is true).  This is
in no way a claim about objects (sons) but about propositions (statements). 
Now according to Lewis, possible worlds are more or less real things.  But
Wittgenstein only exists in this world.  In other worlds there may be
counterparts of Wittgenstein.  Then in one of these worlds there is a
counterpart of Wittgenstein who has a son.  So there is a counterpart son;
and that's not the same as saying there is a son.


*****
Are there any good arguments in favor of a four-dimensional ontology?

Loux 237, anthology(?)

There are two typical views of persistence, endurantism and perdurantism. 
The most familiar is endurantism - for a concrete particular to persist
through time is for it to exist wholly at different times.  The particular
is a 3D object.  Perdurantism holds that endurantism is false; particulars
are made up of temproral parts (or stages or slices) each of which exists at
its own time.  A particular tree, for instance, isn't at this moment wholly
existent; the now-stage of it is.  The tree itself is actually the sum of
all the trees it was, is, and will be.  "This tree" refers to this tree last
month (with leaves), yesterday (several tree cells different), today, and
tomorrow (with a branch chopped off of it).

The appeal of this approach is that it allows for us to explain persistence
through change without contradiction Leibniz's law (which says that if A and
B have different properties than they are not the same).  That is, it allows
us to say "The tree without leaves is the same (tree) as the tree with
leaves." Which is something we want to say (otherwise we get into a horrible
muddle talking about anything; example: "I went to the store yesterday" "No
you didn't, that wasn't you, so someone else went to the store" "No, *I*
went to the store yesterday" ...).  The problem with endurantism is that if
in order to persist an object must exist wholly at different times, then (it
seems) we have to say that the tree without leaves is not the same tree as
the tree with leaves.  And this is crazy.

Now, there may be a way to save endurantism without resorting to 4D
(space-time) objects.  We can time-index all properties; for example "This
tree which has the property of having-no-leaves-now also has the property of
having-had-leaves-last-month." Is there still then a good reason to think
about 4D particulars?


*****
Is there a problem assuming that something exists in more than one possible
world?  Is transworld identity just analogous to identity over time? 
Explain and discuss some possibilities.

Loux 224+,234+, Lewis/Plantinga


*****
When we consider Bob as a cyclist, he seems to be essentially two-legged and
only accidentally rational; but when we consider the same man as a
mathematician, he seems to be essentially rational and only accidentally
two-legged.  What are we to conclude from this concerning the status of de
re modal properties?

Plantinga 145+, Yablo(?), Loux(?)

This can be read (most naturally) not at all as a question about essences
and de re modality (Cyclists are necessarily two-legged) but as modality de
dicto: Necessarily(cyclists have two legs) and Possibly(cyclists are
rational).  That is, all cyclists have two legs but only some are rational. 
We also have, all mathematicians are rational but only some have two legs. 
Knowing as we do that Bob is both a cyclist and a mathematicians, we can see
he falls into the intersection of the sets of Cs and Ms so he is necessarily
both two-legged and rational.  This is not about properties that Bob
necessarily or accidentally has, but about claims of necessity and
contingency that pertain to Bob and his properties.

Might be: Bob qua cyclist is not really the same as Bob qua mathematician,
so there is no conflict in saying:  Cyclist-Bob has A and not-B; Math-Bob has
not-A and B; Math-Cyclist-Bob has A and B.  But then we're never able to
really say anything about Bob qua Bob (as he is).

To try and make a case for de re:  Bob is an individual who is a member both
of the set of cyclists (and so inherits properties from the cyclist
class/kind) and of the set of mathematicans (and so inherits from the
mathematician kind).  Essential properties can be inherited in this way, but
accidential ones can't be used to build up an essence.  That is, accidental
properties are not cumulative.


*****
Do fictional objects exist?  Why or why not?

Parsons, Aune, Plantinga (book), Companion

Fictional objects do exist, but in any physical, material way.  They exist
only within the fictional world in which they have been defined.


*****
What is or might be Leibniz's principle of the identity of indiscernibles? 
Is any such principle true?  What, of philosophical import, hangs on whether
some such principle is true?

Companion

Leibniz: If for all properties P, P(x) is true (that is, x has property P)
if and only if P(y) is true, then x = y.  (This is the same as saying that
if x and y are distinct, they must differ in some property.)

This is a principle that few in metaphysics are willing to give up, but it
seems suspicious to me.  It's not clear what we mean by identity and I think
Leibniz, as often applied, tends to confuse two very different notions of
identity:  numerical and qualitative.  Can't two objects share all of their
properties in common without being the same?  (Consider replicas of each
other, or any number of comparison operators in programming.  We often want
to say that A is the same as B when A and B are numerically distinct.  For
example, "I have that book" meaning "I have another copy of that book".)  Or,
can't the same object persist through change and be numerically identical
while having different properties?  ("This is the same tree it was last month
even though last month it had leaves").

Leibniz as applied to formal systems probably holds, but when we try to
apply it to English sentences things can get too easily muddled.


*****
"If we take away a small part of this house, we shall be left with a house. 
And what we would be left with would surely have been here before we took
away the part.  But since it hasn't the parts this house has, it isn't this
house.  So there are at least two houses here."  Discuss the problems raised
by this argument.

Anthology?

I think this is similar to what I have said above.  This confuses numerical
and qualitative identity.  Qualitatively (with respect to properties) of
course there are two houses.  Numerically, there is only one; it is a house
that has undergone change.