Possible World Semantics Research Papers (original) (raw)

Doctoral Dissertation, official submission 25.05.2017. Outline: "Chapter 1: "The Ontology of Possibility" presents Lewis's modal realism (LMR)
and its analysis of possibility. In particular, it discusses Lewis's stance on modal
truth, which he takes to be absolutely literal. For Lewis, if it is true that there
could have been talking donkeys, then it is literally true that there is world
where there are real donkeys that talk. I argue that it is this view on truth
that lies at the heart of Lewis's rejection of representational, so-called ersatz
approaches to modality and possible worlds, as it is only in virtue of the literal
truth at Lewis's worlds that he can reduce modality to non-modal facts.
This has been challenged, of course. Scott Shalkowski in 'The Ontological
Ground of the Alethic Modality' maintains that no such reduction is possible.
According to Shalkowski, also LMR has to presuppose an unanalysed notion of
possibility, since if it doesn't, its ontological foothold for modality---the plurality
of concrete possible worlds proposed by Lewis---is arbitrary. In the section 'On
Bottlecaps in Hackensack', I show that Shalkowski's argument is unsound, as
it fails to appreciate what Divers has called 'extraordinary' modalities. These
extraordinary cases are exactly the point where modal notions reduce to nonmodal
notions in LMR, and this is ultimately why Lewis's reduction succeeds.
Chapter 2 "LMR and Impossibility" embarks on the actual topic of this thesis,
which is, after all, not possibility but its contrary. It first discusses whether
Lewis in his argumentation for concrete possible worlds accidentally committed
himself also to impossible worlds. After debating the (few) strengths and
(manifold) weaknesses of the so-called 'argument from paraphrase' of everyday
language quantifications over 'ways things could, and could not have been', it
turns to a critical evaluation of the most elaborate proposal for concrete worlds
that are not possible: Kiourti's 'Impossibilist Genuine Realism' (IGR). It is argued
that even though LMR's literalness provides the strongest motivation to
introduce concrete impossible objects into ones ontology, IGR fails to elucidate
what the literal truth amounts to in inconsistent descriptions. It falls prey to a
dilemma: either, truth at its non-Lewisian6 worlds is merely assigned, or IGR
itself is literally inconsistent.
But that IGR is unsatisfactory as an extension of LMR does not mean that
LMR has no need to incorporate impossible content. The second half of the
chapter therefore addresses LMR's virtues and drawbacks as a foundation for a
semantics of intentionality. It is argued that one of LMR's biggest virtues as such
a foundation is that its ontology does not distort the intentional content---or, as
I will call it, that it is faithful to the intentional act in question. Nevertheless,
it is unable to do so in many cases of impossible content. Despite Lewis's
ingenious attempts to incorporate impossible content into his possibilist setting,
some impossible content cannot be accounted for. This content includes what I
have called 'extraordinary impossibilities', which are negations of a specific class
of literal ontological truths of LMR, over which already IGR stumbled. Since
IGR cannot fulfil its ambition to provide a literal semantics for impossibility
statements, and it seems that ersatz 'impossible worlds' are in principle unable
to do so, the discussion turns to a very different approach to intentionality which
nevertheless promises the literal truth of impossibilities: Meinong's theory of
objects.
Chapter 3 lays out the foundations of Meinong's Gegenstandstheorie and
the intentional semantics built on them. It elucidates how Meinong's theory,
though very different from Lewis's, is driven by similar considerations on truth
and literal predication. One of Meinong's core principles is the so-called Principle
of the Independence of the Sosein from Being, according to which objects
need not exist in order to literally possess (or instantiate) the properties intentionally
attributed to them---the totality of these properties being what he
calls the object's 'Sosein', its 'being-so'. This principle is similar to Lewis's approach
to truth as explained in the discussion of his rejection of representational
approaches to modality in chapter 1, and, as will be shown at the end of the
chapter, the demand of literalness leads to the demise of object theory.
Furthermore, Meinong's theory stipulates a plenitude principle for objects.
His Intentionality Thesis claims that every intentional act is directed to an
object. However, this object need not exist, and may well have incompatible
properties, i.e. it can be an impossible object. It is this principle that together
with the Principle of Independence of the Sosein from Being leads the theory
of objects into a dilemma it cannot solve without sacrificing its demand of
the literal truth of intentional property ascriptions. This dilemma is in fact
very similar to the problem IGR encounters: IGR had to accept that either, it
cannot claim that every (impossible) statement whatsoever is true at some of
its concrete worlds, or it is an inconsistent theory. In both cases, then, it is the
double burden of literalness and plenitude that leads to a dilemma.
Chapter 4 Plenitude and Faithfulness returns to the question of how LMR
can be amended to account non-trivially for impossible content. It assesses
which of the two demands, literalness or plenitude, ought to be given up. I
argue that plenitude should not be abandoned if the aim is to provide a materially
adequate semantics for intentionality, and I also argue that this should be
our aim. Since literalness is what prevents both IGR and object theory from
providing a sufficient plenitude of impossibilities to do justice to intentional phenomena,
the conclusion that intentionality and impossibility discourse require
a representational semantics is inevitable. However, the sacrifice of literalness
requires some adjustments in the interpretation of intentional content, i.e. what
was called intentional faithfulness in chapter 2. These changes are discussed in
section 4.2.
Chapter 5 Veracity, Mendacity, and Granularity then discusses so-called 'hybrid'
approaches to 'impossible worlds', viz. theories that add abstract representational
world-surrogates to LMR in order to account for impossible content.
Surprisingly, it turns out that a representational interpretation of 'impossible
worlds' on its own is still insufficient for providing plenitudinous impossible content
while maintaining Lewis's analysis of possibility and its literal account of
truth. The proposals by Greg Restall (1997) and Francesco Berto (2010) build
their truth about impossibility on Lewisian literal truth, and thus inherit the
expressive limitations that derive from it. A different approach by Edwin Mares
(1997) is much better equipped to overcome those obstacles, as it provides the
means to systematically misrepresent the Lewisian ontology, or, as I want to call
it, to lie about it. Section 5.2.3 Systematic Mendacity at Work develops a formal
system along the lines of (Mares 1997) and (Priest 2005), which incorporates
these systemic misrepresentations.
As Mares's theory is coached in the framework of Barwise and Perry's theory
of situations, Barwise and Perry's situation semantics is discussed to answer
the ontological questions that Mares leaves open about his approach. Lastly,
I will reply to an objection put forward by Kiourti against Mares's approach,
which claims that its expressive power is too limited to provide an impossibilist
plenitude.
The concluding chapter of this thesis summarizes its most important points
and the advantages of (Mares 1997) over its competitors. The main conclusion
to be drawn is that there is no literal truth to tell about impossibility, but that
this is not all there is to say about it.