The notes are incomplete and are not a substitute for the essay itself. We don't have a definition like that - at least not one that everyone can agree to. That is, according to evidentialists, only those claims which properly rest on F are epistemically justified. Plantinga turns to an explication of classical foundationalism. A thesis of how a system of belief ought to be structured.
Noetic structures contain a index of depth of ingression.
Plantinga proposes a negative and a positive way of addressing this problem. The negative way seeks to demonstrate that the evidentionlist project will not hold up. The positive way seeks to offer a rationale for Reformed Epistmeology. Plantinga's objection is with the evidentialist who claims that only these propositions are properly basic. This is the negative critique of evidentialism.