As I often tell you, we all live in our own movies inside our heads. Humans did not evolve with the capability to understand their reality because it was not important to survival. Any illusion that keeps us alive long enough to procreate is good enough.
Adams is telling us either directly or by implication that
a. The ability to understand reality is not important to survival.
b. We don't have this ability because we cannot transcend the "movies inside our heads."
c. Knowledge of truth (understanding of reality) is not necessary for procreation; illusions are good enough for procreation.
d. The foregoing propositions are all true.
I will leave it as an exercise for the reader to show that this is an inconsistent tetrad.