
I wish to submit the following abstract.  I am sorry that I am two days 
late with it, but with the university closed and so much to do this time of 
year, you know how it is.  Anyway, here is the abstract: (Please put a 
LaTeX preamble on it.)

Title: Disjunctive Information
Author: Edwin D. Mares
        Victoria University of Wellington


Some situations carry the information that a disjunction $A\vee B$ obtains, 
but do not carry the information that $A$ obtains nor the information that 
$B$ obtains. In such cases, I call $A\vee B$ an {\it unresolved 
disjunction}. Any theory which postulates that denies Laplacian determinism 
will, by virtue of this, postulate situations in which there are unresolved 
disjunctions. Quantum physics, for example, postulates cases in which there 
is disjunctive information. In addition, in order to deal adequately with 
what Barwise and Perry call {\it resource situations} we need to treat 
unresolved disjunctions. In some circumstances we have available to us the 
information that $A\vee B$ without having the information that $A$ or the 
information that $B$. 

The purpose of this paper is to give a semantics for disjunction that takes 
seriously the problem of disjunctive information.  I postulate a relation 
of {\it Possibly determining} ($D$) between an abstract situation, $s$, and 
sets of abstract situations.  These sets of situations represent 
possible extensions, given the information in $s$. Limiting ourselves to 
temporal cases, for the moment, we can think of these sets of situations as 
representing possible futures for $s$. I utilize the relation $D$ 
to give a truth condition for disjunction. That is, $s\models A\vee B$ if 
and only if, for each set of situations $X$ such that $DsX$, there is a 
situation $s\prime$ for which $s\prime\models A$ or $s\prime\models B$.  
Thus, for example, a sea battle will occur on the following day or it will 
not, according to $s$, if and only if, for each future possibly determined 
by $s$, there is a situation in which the sea battle occurs or a situation 
in which the sea battle does not occur.

The formal sections of the paper are concerned with showing that the 
desired properties of disjunction hold in the model theory.  Having 
developed this model theory formally, we apply it to the problems of the 
interpretation of quantum physics -- drawing on a comparison between it and 
Storres McCall's recent work -- and more generally on the problem of 
formally representing indeterminism.  Moreover, we suggest ways in which 
this way of thinking about disjunction suits verificationism better than 
the intuitionistic treatment of disjunction, according to which all 
disjuncts are resolved in all evidential situations.
Ed Mares
Department of Philosophy
Victoria University of Wellington
PO Box 600
Wellington, New Zealand
TEL. [04] 471 5368   FAX [04] 495 5130

