Are there certain moral absolutes that we should live by?
Well the answer to this is yes. Even those who claim that there are no moral absolutes believe in absolutes. I once heard a debate where two philosophers were debating this exact question. The one said, "There is no such thing as absolute truth!" The other man turned to him and asked, "Do you believe that absolutely?" In other words by adamantly insisting that there are no absolutes he was proving the point that he himself believed in at least one absolute. Those who deny God's existence for example sometimes claim that all things are relative...except when it comes to God then they are willing to declare that He absolutely cannot exist.