 But what determines relevance exactly? A popular answer comes from the epistemic contextualists (DeRose 1995; 2009, Lewis 1998; see also the entry on  epistemic contextualism).  Contextualism in the first instance is a view about knowledge, yet it implies that whether an alternative is relevant is determined by the evidential standards in the context. Consider that in order to know whether it is raining, normally one can just take a look out the window. When engaging a Cartesian skeptic, however, that is insufficient. For the skeptic “raises the bar” on the evidence needed to know by imagining bizarre alternatives that he wants ruled out, e.g., the possibility that you are dreaming. Similarly, some compatibilists regard slow switching as a bizarre skeptical possibility which makes exceedingly high the evidential standards for knowledge (Hohwy 2002; Neta 2003 is also pertinent). So if context makes that possibility relevant, one may lose the ability to self-know from the armchair. Still, if switching possibilities are irrelevant, contextualism says that even an externalist can know her own thoughts from the armchair.