 The next distinction we will need, or more accurately, family of distinctions, is between internal and external relations. What makes them members of a single family is that a relation is internal if its holding between things is somehow fixed by the things themselves or how those things are; external relations are relations whose holding between things isn’t fixed this way. Different versions of the internal-external distinction correspond to different explanations of how internal relations are fixed (Ewing 1934: 118–36; Dunn 1990: 188–192; Hakkarainen, Keinänen &amp; Keskinen, 2019). We don’t need to describe every version of the distinction but here are three that are essential to understanding the contemporary debate.