 The process problem, in contrast, arises because subjects engage not only in episodic remembering but also in episodic future thinking and episodic counterfactual thinking and because (as we will see) these forms of episodic imagining closely resemble remembering. For example, one might imagine a future event or a counterfactual event by drawing on information deriving from similar past events. Hence, when one engages in episodic thought, one is faced with the problem of determining whether one is remembering a past event or imagining a future or counterfactual event. Subjects may cope with this problem by relying on a form of metamemory which might be called “process monitoring”; whereas source monitoring relies primarily on content-based markers, process monitoring may rely additionally on phenomenological markers, such as the feelings of familiarity and pastness discussed above, and formal markers, such as the subject’s intention to remember or imagine (Hoerl 2014; Urmson 1967).