 However, simply rejecting C2D in favor of E2D does not yet provide any positive account of what it is to entertain an epistemic scenario W, and how we should update our beliefs in the light of the supposition that W is actual. Without these details, it’s impossible to determine whether the Core Thesis is true. Perhaps it’s impossible to consider a scenario as actual without presupposing one’s own existence, or perhaps our best epistemic methods for updating our beliefs presupposes the existence of those very beliefs; or perhaps there is no way of thinking about the world that doesn’t rely on some further empirical assumptions about the world.