Metaphysics: An Overview
Identity And Existence.
Questions of identity are about what an individual is,
what makes it that makes it that individual (or that kind of thing) and
not something else. Questions of existence are concerned
with whether there is something having that identity, whether
that identity is instantiated.
We can now say that a real individual is an identity+an existence.
Properties And Level.
The identity of an individual can be conceptually decomposed
into its properties. The existence of an individual can also
be thought of as a property, but a property of a different
kind, a higher level property. To say that an identity
exists is to say that it (that is, the bundle of properties
which make it up) have the property of existence -- but
in this case existence is a property had by other
properties, so it is a meta-property, or higher-level property.
For present purposes, 'property' excludes higher-level
properties.
Intrinsic And Relational.
An intrinsic property is a fact about the identity of a
single individual, which can be discerned by
examining that individual alone. Relational
facts concern two or more individuals. Some
relations are 'internal', meaning that they
can be deduced from the intrinsic properties of
the indivuals concerned. 'Laurel is lighter than Harvey'
is an example of the internal relation '__ is lighter than__'.
We will only be interested in external relations, which
cannot be deduced from any facts about intrinsic properties.
Spatial relations such as ('__ is to the left of__')
are examples of external properties.
Modes Of Existence
We have so far treated existence as a yes-no thing. But we
can say more about an identity than that is exists or not.
Consider something which exists at time A, is destroyed during time
B, and re-appears at time C. What we can say about it during time B is that it
was possible, since it existed before, and will exist again.
These sorts of complex facts about existence will be called 'modes'.
Relational Modes.
So far we have treated modes as being intrinsic. But there are
also relational modes, which are more commonly known as
causal relation. To say that two events or things are causally related is
to say that one owes its existence in some sense to the other; if A had
not occured, B would not have occured. The difference between
a causal relation as a relation of existence, and a raltionship of identity
is underlined by Hume's famous argument to the effect only succession,
and not causality, can be oberved.
Space And Time
The causal relation is the distinguishing characteristic of time.
Events separated by purely spatial intervals -- that
is simultaneous events -- cannot influence one another.
Spatially separated events can influence each other
so long as there is a time interval as well. To put
the same point another way, there can be no instantaneous
transmission of causal influences, a corollary of which is
that there must be a maximum velocity in the universe.