Final answer:
Different philosophical perspectives contribute to the understanding of justification and truth values in logic and epistemology.
Step-by-step explanation:
In the study of justification and truth values in logic and epistemology, different philosophical perspectives contribute to the understanding of these concepts. For example, Artemov and Fitting, Shramko and Wansing, Moschovakis, Halbach and Leigh, and Hasan and Fumerton provide various insights and challenges to the notion that the truth set of an axiom is the empty set, particularly in the context of foundationalist and intuitionistic theories.