  The last distinction is especially controversial, as there are philosophers—from Whitehead (1919), Broad (1923), and Russell (1927) to Quine (1950), Lewis (1986c), Heller (1990), Sider (2001) and many others—who conceive of objects as four-dimensional entities that extend across time just as they extend across space. Some such philosophers would accordingly draw no metaphysically significant distinction between objects and events, treating both as entities of the same kind: an object would simply be a “monotonous” event; an event would be an “unstable” object (Goodman 1951). More generally, the relevant distinction would be one of degree, and while ‘event’ is standardly applied to things that develop and change fast in time, ‘object’ would apply to those things that strike us as “firm and internally coherent” (Quine 1970). On the other hand, there are also philosophers who reject the distinction on the side of events, by construing at least some such entities—e.g., processes—as continuants: what is happening at any moment when an apple is decaying or a person is walking down the street is the whole process, not just part of it (Stout 1997, 2003, 2016; Galton 2006, 2008; Galton &amp; Mizoguchi 2009). This view, in turn, admits of several variants and alternatives, e.g. based on different ways of understanding the notion of a continuant (Steward 2013, 2015) or its relation to the stuff of which a continuant is composed (Crowther 2011, 2018).