 Two final comments. Nagel (1971) argues that there can be indeterminacy in synchronic unity, too (see  Section 6). One can sympathize with Parfit about diachronic unity and yet have reservations about Nagel on synchronic unity. Likewise, one should distinguish the question of whether diachronic unity can be intransitive from the question discussed in  Section 6  of whether synchronic unity can be intransitive.