From Wikipedia (can you tell I find myself here a lot):
Secular Humanism is a secular philosophy that espouses reason, ethics, and justice, and specifically rejects supernatural and religious dogma as the basis of morality and decision-making. Secular Humanism is a life stance that focuses on the way human beings can lead good, happy and functional lives.
Secular Humanism (capital “H”) is distinguished from various other humanisms. Though Secular Humanism posits that human beings are capable of being ethical and moral without religion, or God, that is not to say it assumes humans to be inherently or innately good. Nor does it present humans as “above nature” or superior to it; by contrast, the Humanist life stance emphasises the unique responsibility facing humanity and the consequences of our ethical decisions.
The term “Secular Humanism” was coined in the 20th century, and was adopted by non-religious humanists in order to make a clear distinction from “religious humanism”. Secular Humanism is also called “scientific humanism”. Biologist E. O. Wilson called it “the only worldview compatible with science’s growing knowledge of the real world and the laws of nature”.
Fundamental to the concept of Secular Humanism is the strongly held belief that ideology–be it religious or political–must be examined by each individual and not simply accepted on faith. Along with this belief, an essential part of Secular Humanism is an ongoing search for objective truth, which is seen to be continually adapting and changing.
Secular Humanism describes a world view with the following elements and principles:
Need to test beliefs – A conviction that dogmas, ideologies and traditions, whether religious, political or social, must be weighed and tested by each individual and not simply accepted by faith.
Reason, evidence, scientific method – A commitment to the use of critical reason, factual evidence and scientific methods of inquiry in seeking solutions to human problems and answers to important human questions.
Fulfillment, growth, creativity – A primary concern with fulfillment, growth and creativity for both the individual and humankind in general.
Search for truth – A constant search for objective truth, with the understanding that new knowledge and experience constantly alter our imperfect perception of it.
This life – A concern for this life (as opposed to an afterlife) and a commitment to making it meaningful through better understanding of ourselves, our history, our intellectual and artistic achievements, and the outlooks of those who differ from us.
Ethics – A search for viable individual, social and political principles of ethical conduct, judging them on their ability to enhance human well-being and individual responsibility.
Building a better world – A conviction that with reason, an open exchange of ideas, good will, and tolerance, progress can be made in building a better world for ourselves and our children.
A Secular Humanist Declaration was issued in 1980 by The Council for Democratic and Secular Humanism (CODESH), now the Council for Secular Humanism (CSH). It lays out ten ideals: Free inquiry as opposed to censorship and imposition of belief; separation of church and state; the ideal of freedom from religious control and from jingoistic government control; ethics based on critical intelligence rather than that deduced from religious belief; moral education; religious skepticism; reason; a belief in science and technology as the best way of understanding the world; evolution; and education as the essential method of building humane, free, and democratic societies.