 Is causation in the world, as expressed by HRT, extensionally equivalent to causation in the mind? The difference between the two definitions seems to be that condition (iii) of HRT is replaced by the following condition: \(c\) of type \(C\) makes us infer \(e\) of type \(E\). While HRT does not require the presence of an epistemic agent, the other definition seems to require such an agent and is thus mind-dependent. And an epistemic agent may infer an event from another event, even though there is no regularity connecting the two events. Having said that the two definitions are not extensionally equivalent, the definitions can be read in ways which make them coextensive. The epistemic agent of the second definition, for example, can be seen as a hypothetical omniscient observer who always and only infers in accordance with all and only true regularities (for details, see Garrett 1997: Ch. 5).