 A question that has received increasing attention in recent years is whether causation is an ‘invariant’ relation or whether, instead, the truth of a given causal claim varies according to the context within which it is under discussion. (Note that ‘invariant’ is often used to describe a causal relationship that is stable across a wide range of different circumstances; this is not the meaning of ‘invariant’ as it is being used here.) There is a wealth of evidence that people’s causal judgements are sensitive to contextual factors (Hilton &amp; Slugoski 1986; Cheng &amp; Novick 1991; Knobe &amp; Fraser 2008; Hitchcock &amp; Knobe 2009; Clarke et al. 2015; Kominsky et al. 2015; Icard et al. 2017); however, in principle one might hold the invariantist line and insist that what varies with context is not truth but merely assertibility.