Say that a proposition p is shifty provided that there are worlds w1 and w2 at which p holds, and a proposition q such that q grounds p at w1 but q does not ground p at w2.
A proposition p is non-shifty provided that either it cannot have a ground or there is some proposition q such that p entails that q grounds p.
The proposition that Obama or McCain is president is shifty: in some worlds it is grounded in Obama being president and in others it is instead grounded in McCain being president.
Propositions of the form of the proposition that N exists are non-shifty, if "N" directly rigidly refers to a substance.
Propositions expressed by typical simple subject-predicate sentences are shifty if trope theory is true. For instance, that I am sitting is grounded by the proposition that I have s1, where s1 is the trope of sitting that I actually have, but could have been equally well grounded by the proposition that I have s2, where s2 is some other trope of sitting. On the other hand, if Platonism is true, then sentences whose subject term directly refers and whose predicate expresses a property are going to be non-shifty, as in every world where they are true, they are grounded by some proposition of the form of the proposition that N exemplifies P.
"For instance, that I am sitting is grounded by the proposition that I have s1, where s1 is the trope of sitting that I actually have".
ReplyDeleteI would like to show that that idea, and the notion of possible worlds, is transcendental realism, to which we need not be committed.
An assumption is that "possibile worlds" describes any worlds whatsoever, and also describes the totality we imagine arises from the sum of any worlds whatsoever. But the term "possible" is insufficient for this task. It cannot describe or refer to worlds that we think we can describe, identify or refer to, but cannot, or describe their totality. I might also suggest that we cannot identify or make a reference to that totality because it is an insignificant proposal a la Kant (cosmological ideas) and Wittgenstein.
In other words, possible worlds and s1 assume that actuality and/or existence is prior to the means of identifying them: and this is transcendental realism. So,in s1, actual sitting describes an ontology where objects are given as existing in such and such a way, in spite of the absence of any conditions for identifying objects as actually sitting or being in such and such a way.
New objects have been introjected into transcendental realism ("worlds"), objects with new behaviours. However, this complication is no saving grace as it still leaves untouched the problems inherent to their transcendentally real ground. How far these problems have resurfaced in your, or any, analysis of a transcendentally real (possible) world(s) I cannot say at this point.