The second person, since his presuppositions do not allow him to find the cause of the murder inherent within the murderer, must look elsewhere for the cause. Another example would be the scientist who believes in an ordered universe created and sustained by a knowable, reasonable God. This scientist can study his particular field with the understanding that he can discover the laws that God uses to govern the cosmos. Another scientist, who believes that the universe was created by chaotic event called the Big Bang and maintained by chance, has no assurance that if he discovers that two plus two equals four today, it will not change tomorrow or that a constant in an equation today will not become a variable tomorrow. Presuppositions are ideas accepted and believed beforehand that affect how we interpret information we are currently receiving.
Integrity is the next important aspect of a world-view.
The second part of integrity deals with flaws created by a conflict between a world-view and the substance of reality. While the first lie may stand, or be non-disprovable, all of the subsequent lies that are stacked on top of the first to cover it up eventually collapse the first. The crux of any world-view, any presupposition, is faith. A Christian cannot prove empirically to anyone that God exists. An evolutionist cannot prove that similar genetic structure means common ancestry.