Suppose that one thinks, as I am inclined to, that principles of composition—of the sort of: whenever there are some things, there is something that is a sum of them—are necessary if true as the result of being ‘analytical,’ at least in a certain sense (which I won’t pause to explicitly state ;-)).
“Existence claims are, seemingly, never analytic; so it seems that a conditional whose consequent was an existence claim could be analytic only if the antecedent asserted the existence of the thing in question. But if the sentence ‘If some objects are in conditions C, then there exists something that is composed of those objects’ is informative then the antecedent does not assert the existence of the thing in question (namely, the sum of the objects in conditions C). The sentence is synthetic, then; there is nothing in the concept of certain things meeting certain conditions that there is a fusion of those objects.”
This seems puzzling to me. Consider the following:
Whenever something is a proper part of another, there is something that is part of the latter but not of the former.
I take it that this has a good claim to be necessary if true as a result of analyticity. And it has the relevant considered form: a conditional whose consequent is an existence claim. In a certain sense, such existence is not “asserted” in the antecedent—hence the “informativeness”—; in another sense, it is (“implicitly”) so asserted—hence the analiticity—.
Mutatis mutandis, Ross’ opponent contends, for the envisaged principles of composition.