Such a view would attempt to formulate haecceitism as the following thesis: World Indiscernibility: There are distinct possible worlds that are qualitatively indiscernible.
As for sensitive consumer sectors such as retailing and transport, the authors conclude that the impact ranged "between indiscernible and modest".
With regard to two visually indiscernible paintings, an original and a copy, Goodman addresses the question whether there is any aesthetic difference between the two pictures (1976, 99 102).
For modal realists who would reject Qualitative Supervenience, qualitatively indiscernible possible worlds can differ with respect to which de re possibilities they represent.
For example, if one holds that all propositions are qualitatively indiscernible, an unrestricted application of PII will cause broad problems for such a view e.g., by ruling out the existence of more than a single possible world.
For, if some worlds differ haecceitistically but are alike with respect to the distribution of physical properties, then, contrary to physicalism, possible worlds or maximal possibilities can be physically indiscernible yet fail to be indiscernible simpliciter.
According to some proponents of the Simple View, it seems possible that that the pre-fission individual be identical to one of the post-fission individuals while, in other physically and psychologically indiscernible worlds, the pre-fission individual is identical to an apparently different post-fission individual.
This has immediate implications for the Principle of the Identity of Indiscernibles which, expressed crudely, insists that two things which are indiscernible, must be, in fact, identical.
Doubts about the intelligibility of such a plurality arise because of perplexities concerning the individuation and separation of any pair of necessarily indiscernible objects, and because positing the existence of a plurality of such objects is metaphysically extravagant and gratuitous.
This is significant for Clarke's Newtonianism, because if space is real and absolute, then the identity of indiscernibles must be false because regions of space are indiscernible with respect to their intrinsic and (prior to the creation of the world) their extrinsic properties.
Leibniz thinks that the PSR rules out the possibility that there could be two or more indistinguishable, that is, indiscernible, things (A VI, iv, 1541/AG 42).
