In the Poison of Subjectivism C.S. Lewis discusses how our perception of good and evil can be skewed. We are fallen beings by nature and even though we have a knowledge of good and evil we cannot clearly define what is right and wrong.
One of man's greatest sins is pride. It is because of this sin that we believe we can classify all acts into a scale of good and evil. We all know that gossip and murder are both sins, but for some reason we have decided that murder is a more serious sin than gossip. We do not have the perspective to judge these sins. The reason that we might determin that sins like gossip are lesser sins is probably because we perform this sin more often.
All of our logic is based on facts that are not valid. There is nothing in this world that we can base any hypothesis on. We get all our information from our six senses which can never be fully trusted. Only God can judge, because he is the only one that sees everything.