 A few quick notes before moving on. Following most of the literature, the term “higher-order evidence” is used here, although it would be more accurate to speak of higher-order evidential effects or higher-order evidential import (since one piece of evidence may be relevant to a person’s beliefs about many different subject matters, in a number of different ways). And like most of the literature, the focus is on higher-order defeat, rather than higher-order confirmation, even though these possibilities go hand in hand. Some of the issues discussed in this article are discussed in more detail in the entry on  epistemic self-doubt.  Finally, although the higher-order evidence debate has its roots in the literature on disagreement, this entry focuses on the simpler, single-person case introduced above and mostly omits disagreement.