The test of congruence under total evidence as used in systematics has been tied to a Popperian philosophy of science, but is here shown to be related to the coherence theory of truth in metaphysics and thus to coherentism in epistemology. Since the test of congruence is coherentist, the contextual (theoretical) background of initial character conceptualization cannot be ignored as is suggested by some proponents of the total evidence approach. The relative merits of a total evidence approach versus conditional data set partitioning are considered, and whereas both have their merits and drawbacks, either approach requires causal grounding of character statements (statements of homology), at least approximately and defeasibly. The conclusion is that character congruence is a necessary, but not also a sufficient, condition for phylogeny reconstruction.
Systematics; total evidence; test of congruence; Popper