 All these views agree that there is something that it takes for us to persist—that there are informative, nontrivial necessary and sufficient conditions for a person existing at one time to exist at another time. A fourth view, anticriterialism, denies this. Psychological and physical continuity are evidence for persistence, it says, but do not always guarantee it and may not be required. The clearest advocate of this view is Merricks (1998; see also Swinburne 1984, Lowe 1996: 41ff., 2012; Langford 2017; for criticism see Zimmerman 1998, Shoemaker 2012). There are anticriterialist views about things other than people as well. And there is debate about how anticriterialism should be understood (Olson 2012, Noonan 2011, 2019).