Secular humanism, often simply called humanism, is a philosophy or life stance that embraces human reason, secular ethics, and philosophical naturalism while specifically rejecting religious dogma, supernaturalism, and superstition as the basis of morality and decision making.
Secular humanists believe human beings are capable of being ethical and moral without religion or belief in a deity. It does not, however, assume that humans are either inherently good or evil, nor does it present humans as being superior to nature. Humanist do not believe that a supernatural exists. They believe it is a myth. There is only the natural realm (no angels, Satan, God etc.)
Secular humanism is basically an atheistic approach to live. It stands polar opposite to a Christian worldview and has become the dominant influence in American culture. Christians need to understand its holistic nature and why it poses such a menacing threat to the Christian faith. Francis Schaeffer clearly seen the direction it would take the world and tried to warn the Christian community of the dangers it posed to the faith.