 Condition (iii) relates a particular instance of causation, \(c\) is a cause of \(e\), to the class of all like cases, the types of \(c\) and \(e\). Hume takes causation to be primarily a relation between particular matters of fact. Yet the causal relation between these actual particulars holds in virtue of a certain regularity. Any causal relation thus supervenes on a regularity in the sense that there can be no change in the causal relation without a change in the regularity. Any regularity, in turn, supervenes on particular matters of fact: there can be no change in the regularity without a change of particular matters of fact. Whether a regularity is true is thus determined by which particular matters of fact obtain. Likewise, whether a causal relation obtains is determined by which regularity obtains. In the end, only the particular matters of fact determine whether or not a causal relation obtains, since the relation of supervenience is transitive. (For details, see the entries on  supervenience  and  David Lewis, section on Humean supervenience.)