Modal Realism/Bigelow/Pargetter: should accept a correspondence theory for modal language.
Possible worlds/Bigelow/Pargetter: Thesis: Possible worlds exist. But we have not yet said anything about what they are made of and what they are. Different kinds of realisms will assume different kinds of possible worlds.
Truthmaker/Bigelow/Pargetter: we have not said anything yet about how modal sentences are made true.
Realism/Possible Worlds/Bigelow/Pargetter: all realisms will say that it is possible that there is a world that represents the actual world as being represented as being in a certain way. ((s) >Stalnaker). Of course, all but one of them represent it wrong.
Possible worlds/Bigelow/Pargetter: are therefore representations of the actual world. "Representation" is only a technical term,...
... and not exploratory.
Possible worlds: represent not only the actual world, but also other possible worlds!
Modal realism/Bigelow/Pargetter: in this way of speaking, we can then differentiate between what they see as possible worlds.
Modal Realism/Possible worlds/Bigelow/Pargetter: three varieties:
1. book theories = maximally consistent sets of truthmakers - "books".
2. replica theories = thesis: worlds are not carriers of truth but replicas ((s) i.e. objects).
Substitutes: David Lewis.
3. property theories: = thesis: worlds cannot be understood as books, they are a multitude of books. This means that there is a multitude of truths ((s) within a possible world.
There are three sets of truthmakers here:
(a) set of sentences
(b) set of propositions
(c) sets of beliefs.
Modal Realism/Bigelow/Pargetter: modal realism must be able to explain possible worlds without using any modal basic concepts. And that is harder than it looks at first glance.
There is a thesis that this is not possible at all: modalism.
Definition Modalism/Bigelow/Pargetter: the thesis that it is not possible to define modal terms in a non-modal way.
Representatives: Lycan 1979, Plantinga 1974,1976,1987, van Inwagen (1984: some modalities do not need to be defined in more fundamental terms.)
Modalism: according to Hume's critique of the naturalistic fallacy (avant la lettre) one could express it with the slogan thesis "No must from the is". That is to say, moral desires cannot be deduced logically and entirely from outer-moral facts.
Bigelow/Pargetter: from this we can gain two attitudes:
a) there are no moral truths, (moral nihilism) or
b) some moral truths we must take as undefined basic facts.
Modal logic/Bigelow/Pargetter: Problems with the moral "must" are reflected in the metaphysical "must".
Correspondence theory: is the theory which brings the problems, because without it modal basic concepts would be no problem. But since we want to keep the correspondence theory, we need better access to possible worlds.
Possible solution: cannot we just say that some things cannot be described without modal terms? Analogue:
For example, name: a fantasy name like "Gough" could refer to something non-linguistic that is not a carrier of truth. In any case, we have to assume an individual. We are assuming correspondence with this. If we tried a description instead, it would reintroduce a name again. Therefore, we would have to accept some names as undefined basic terms. But that would not yet be a threat to the correspondence theory.
(Question/s): many basic terms would make a correspondence relationship superfluous, because something undefined does not have to be shown?)
Modal Basic Term/Correspondence/Bigelow/Pargetter: analogously, we can assume that modal basic terms are not a threat to correspondence: e.g.
Conchita can play guitar
is true by correspondence between this statement and things in the world.
The property of being able to play the guitar is assumed. (Bigelow/Pargetter pro).
Modal terms/Bigelow/Pargetter: their threat comes not only from the correspondence theory, but also from their supervenience of non-modal properties.
Supervenience/Definability/Definition/Bigelow/Pargetter: a supervenience would guarantee the definition of modal properties in non-modal terms!
Problem: to do so, we would have to allow an infinite number of complex definitions. This would at least allow a characterization of modal terms.
Possible worlds/Bigelow/Pargetter: in the following we will consider attempts to characterize possible worlds in non-modal terms.
Characterization/Bigelow/Pargetter/(s): less than a definition, from many individual cases.
Method/Bigelow/Bigelow/Pargetter: whenever a theory leads to modal basic concepts, we will put this theory aside. This is because it cannot then play an explanatory role within the Humean Supervenience. Not because the corresponding possible worlds did not exist.
Modal Realism/Lewis/Bigelow/Pargetter: his extremely concrete modal realism has the advantage that it would explain many things if it were true. And most people agree on that. Then why has the unbelieving gaze not disappeared? His theory has nothing irrational either.
VsLewis: to disprove him, you would have to adopt one of two strategies:
1. the initial probability is 0 (instead of something above)
2. even if the probability increases in the course of time, the increase would be infinitesimal.
Ad 1.: the probability cannot increase from zero. Nevertheless, the question remains whether it is ever rational to attribute a probability of 0. Especially not Lewis' theory.
LewisVsVs: that would lead to a trilemma:
(1) the opponents might realize that a greater intelligence has thought longer about it than they did and therefore the probability is > 0 and that he means what he says.
(2) they could assume that he does not mean what he says
(3) they could say that sometimes it is rational,...
... to assign a chance of zero to something, which a serious and intelligent authority has said.
Rationality/Bigelow/Pargetter: from Lewis' Trilemma there would only be (3) left, and thus the question of rationality. Rationality should not lead us to the acceptance of (3). But it also remains, however, even if Lewis's position is only considered to be very unlikely.
Problem: to deny someone rationality in an area to which, in principle, one has no better epistemic access than the critizised.
Ad 2. (the probability remains infinitesimal): i.e. it does not matter how much evidence we teach.
BayesVs: this could only happen after the Bayes-theorem,...
...if the required probability for each future document should be practically 1. And that is unacceptable._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
J. Bigelow, R. Pargetter
Science and Necessity Cambridge 1990