Question
Counterexamples to this statement can be resolved by finding an irreflexive symmetric relation, which is Quine's “weak” form of a related property. This statement is invoked in a passage that argues the universe would be no different if God moved it “forward in a right line,” contra substantivalism. Interlocutor B rejects this statement by imagining a perfectly symmetrical universe consisting of two iron, mile-wide spheres in a paper by Max Black. The application of this statement to intensional contexts is called the (*) “masked man” fallacy. This statement can be expressed in symbolic logic as (read slowly:) if for all properties F, Fx if and only if Fy, then x equals y. In letters to Samuel Clarke, this statement was derived from its formulator's Principle of Sufficient Reason. For 10 points, name this principle that states that any two objects with all the same properties are the same. ■END■
ANSWER: the identity of indiscernibles [or Leibniz's Law; accept the indiscernibility of identicals] (The first clue refers to weak discernibility, also called weak discriminability. The second clue draws from the Leibniz-Clarke correspondence about the nature of space.)
<VD, Philosophy (Early Modern)>
= Average correct buzz position
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