For the Christian realist, the overwhelming tendency among human beings to act in their perceived self-interest is one but not the only effect of sin. Sin also distorts how human beings perceive themselves in relation to others. This introduces a gap between what people perceive to be in their interest and what is actually in their interest, thereby hampering their ability to gauge self-interest accurately. Human beings are driven by self-interest, but are bad at determining what their self-interest is.
