 We should expect absolute borderline cases to arise for unfamiliar cases. Where there is no perceived need for a decision, criteria are left undeveloped. Since philosophical thought experiments often involve unfamiliar cases, there is apt to be intrinsic uncertainty. W. V. O. Quine was especially suspicious of the far-out hypotheticals popular in the literature on personal identity. He globalizes his doubts about determinate answers in his thesis of radical translation: for any language, there are indefinitely many, equally adequate rival translation manuals. 