 Another formalism closely related to default logic is Moore’s Autoepistemic Logic  (Moore 1985).  It models the reasoning of an ideal agent reflecting on her own beliefs. For instance, sometimes the absence of a belief in \(\phi\) may give an agent a reason to infer \(\neg\phi\). Moore gives the following example: If I had an older brother, I would know about it. Since I don’t, I believe not to have an older brother. 