Primitive Directionality and Diachronic Grounding

Eternalists believe that there is no ontological difference between the past, present and future. Thus, a challenge arises: in virtue of what does time have a direction? Some eternalists (including Maudlin (2007), Oaklander (2012) and Tegtmeier (1996, 2009, 2014, 2016)) argue that the direction of time is primitive. A natural response to positing primitive directionality is the suspicion that said posit is too mysterious to do any explanatory work. The aim of this paper is to relieve primitive directionality of some of its mystery by offering a novel way to understand the phenomenon in terms of the recently popularised notion of grounding.