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TIME

*****
Mark Heller, Things Change:

Heller is a four dimensionalist (perdurantist).

Common motivation for and objection to 4D is its account of persistence
through change.

Matter fills up not just space but spacetime.

An understanding of temporary parts is no more or less basic than of the
whole they compose.

The problem:  inconsistency of the claim that we survive changes and the
indiscernibility of identicals (if x and y differ in any properties, then
they are not identical).  Example: Dr Mark has a beard but little Markie
does not, but we want to say that they are mathematically identical (one
and the same object).

4D Solution: objects have temporal parts.  Heller is composed of Dr Mark,
little Markie, etc.  To say Heller has survived change is to say that he is
composed of temporal parts with different properties.  Heller changes; not
his parts (which are different).  

Against 4D:  (1) there are other ways to get around persistence without 4D;
or (2) this does not adequately explain change. 

According to (1) the having of properties can be relativized to time. 
(Heller has a beard in 1991 is to say there is a true 3-place relation
R(Heller, beard, 1991)=1.

According to (2) 4D does not allow for real change (Lawrence Lombard). 
Instead, there is a static conception in change in which one object is
replaced by another distinct object (as in a motion picture).  The problem
here is that this misunderstands 4D by taking the instantaneous parts to be
more ontologically real than the whole composed of them.  Under 4D these
instantaneous parts aren't objects, but only parts of the one single object. 

Also, according to (2) one can argue that the thing itself isn't really
changing since it has the same properties at all times; only it's parts
differ.  A certain highway which is flat in Illinois and hilly in NY doesn't
change; it has two different parts.

But time not really analogous to space:  temporary direction, unlike spatial
direction, is not a matter of human perspective.


*****

Peter van Inwagen, Four-Dimensional Objects

Representations of Descartes made out of wires and three theories:

(1)  "Descartes was hungry at t1" means hunger is ascribed to an object that
occupies a particular spacetime region; "D was thirsty at t2" refers to a
distinct object.  (Sounds to me like the 3D critic's view of 4D with no
persistence.)

(2) "Descartes" always refers to the whole Descartes (at all times), so
"D was hungry at t1" means the whole D has the property of having a t1-part
that is hungry.  (Sounds to me like 4D with persistence.)

(3) All regions are occupied by the very same object, so "D was hungry at
t1" means D satisfies a three-place relation (D, hungry, t1).  (Sounds to me
like 3D; this is Inwagen's view, it's really 3D with a union operation.)

Replies to arguments against theory 3; I outline some:

(A) Arg: What exactly fills one region of spacetime cannot be what exactly
fills another.  Re: Not so; this is true of space but not via analogy of
time.

(C) Arg: Must have three-place relations or time-indexed properties.  How
are these to be understood as two-place relations (as theory two defines "x
has F at t" as "the t-part of x has F")?  Re: "x has F at t" may be
primitive and "x has F" derived.

(D) Arg: D1 is shaven and D2 is bearded, so they are not identical.  Re:
This is to misunderstand; there is no D1 and D2, only D who is shaven at t1
and D who is bearded at t2.  "D was born on day n" is always, timelessly
true; "D was bearded at t2" is similarly timelessly true.

(E) Arg: if D is fully there at every moment, what occupies the entire
spacetime region and what properties does it have?  Re: still D.  The union
of D and D is D.  The properties it has are precisely those that D had at
every point in time.

Argument against theory 2:
How can theory 2 with sum of temporal parts account for the claim that D
might have lived for a different length of time?  Believers of theory 2 will
have to maintain that temporal parts are modally inductile, and as the sum
Descartes is also a large temporal part he is modally inductile and could
have have lived for a different amount of time.  Etc.


*****
Michael Rea, Temporal Parts Unmotivated

perdurantism has been the challenger to endurantism.  Perdurantism has been
recommended on the grounds that (1) it solves problems of material
constitution, (2) is suggested by relativity, (3) is the only view that
makes sense of change, (4) is the only view consistent with Humean
supervenience, and (5) makes better sense with regard to fission. 
Ultimately, Rea does not believe that perdurantism succeeds on any of these
grounds.

I want to know more about (1) but it's not in this article; and should
perhaps review (5), but here I will only consider (3): the problem of
temporary intrinsics, as according to David Lewis.  Lewis-bent is bend and
Lewis-straight is straight so it seems that Lewis-bent is not equal to
Lewis-straight by ind of id.  Lewis claims the only ways to solve this
problem without temporal parts are to claim that these are not intrinsic
properties but disguised relations or to deny the reality of past and future
times, and neither of these are acceptable to Lewis. Johnston's adverbial
solution is to say not that "Lewis-best has the property of being bent" but
that "Lewis has-at-t the property of being bent".

 
*****
Theodore Sider, Four-Dimensionalism

Persistence through time is like extension through space.  A road has
spatial subregions, and an object has temporal parts.  Sider is in favor of
4D via an argument from vagueness.  He also considers unrestricted
mereological composition (see pp 19-27).



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CYCLIST

*****

Richard Cartwright, Some Remarks on Essentialism

essentialism is the doctrine that among the attributes of a thing some are
essential (necessary, could not have lacked), others merely accidental
(contingent, could have been otherwise).

Quine: Mathematicians may be said to be necesarily rational and not
necessarily two-legged (bipedal); and cyclists necessarily two-legged and
not necessarily rational?  So what about an individual who is both a
mathematician and a cyclist?

de dicto: 'M-are-r' is a nec truth and 'C-are-b' is a nec truth.
de re: 'Every M is such that he is nec r and not nec b' and 'Every C is such
that he is nec b and not nec r'.
The de dicto presents no problem, but the de re seems to. Say Wilson is a
mathematician and a cyclist.  Is Wilson (he himself) necessarily rational? 
To say so seems to put emphasis on him as an M rather than as a C.  (My
thought: W-qua-M vs W-qua-C.)

One interpretation:  M is nec c if and only if it is necessarily false that
M lacks c.  This allows us to get from de re to de dicto.


*****
Rome Clark, On What Is Naturally Necessary

Necessity in Quine's example is relative.  Tautological predicates aside, it
is never the case that a concerete individual is necessarily anything; only
that it is necessarily something relative to the kind of thing it is. 
Relative to being a cyclist, this man must have a pair of legs.  Relative to
being a mathematician, he must be rational.

*****

Ruth Barcan Marcus, Essential Attribution

Quine argues against a genuine mode of essentialism.  Consider Winston, the
mathematician cyclist.  According to a colleague, "unlike the rest of us, he
is essentially a cyclist, not a mathematician."

Two kinds of essentialism:  Aristotelian and individuating.

*****

Alvin Plantinga, De Re et De Dicto

Plantinga takes the real depth of Quine's objection to be: "As are nec Bs"
must if it means anything mean "It is nec that all As are Bs"; nec resides
in the way we talk about things, not in the things we talk about.  de re
only makes sense in terms of de dicto.

An object has a given property essentially just in case it couldn't
conceivably have lacked it.