  The use of the term ‘essential’ in weak and strong AKI is important. Imagine that one's knowledge basis for proposition p is quite complex, including a number of different elements. Perhaps one has amassed a good bit of evidence concerning p, and the cumulative effect is to make up one's knowledge basis for p. It may be that some element in this evidence base is inessential, in the sense that even if one were to delete that element, the remaining evidence would still constitute a knowledge basis for p. A case like this might well arise when one has amassed an over-abundance of evidence, perhaps with the aim of being especially careful and diligent. Without the use of the term ‘essential’ in the above definitions, we would allow for cases in which a person was capable of becoming aware of what was in fact an inessential part of her knowledge basis for p. This would unfairly saddle the internalist with an unnecessarily implausible position, and the use of the term ‘essential’ is designed to avoid that consequence.