This booklet contains the first two Humanist Manifestos. The first was written in 1933, and the second in 1973. Both documents are based, not surprisingly, on a naturalistic foundation. This is forcefully brought out in the first manifesto which states, "Holding an organic view of life, humanists find that the traditional dualism of mind and body must be rejected." This view recognizes that humans have knowledge of this world, and this world only. Any claim of "knowledge" about another world is simply not knowledge, in that it is based solely on religious authority.
The second manifesto is a bit longer, and a bit more comprehensive. This is to be expected as knowledge advances, and as people have time to ponder events and principles in the intervening years. My favorite quotes are under the section entitled, "Ethics." That section opens with this beautiful statement, "We affirm that moral values derive their source from human experience. Ethics is autonomous and situational, needing no theological or ideological sanction. Ethics stem from human need and interest." A little thought brings to mind how this kind of thinking is conducive to the betterment of the human condition, as opposed to a religious worldview. Even those in religious organizations who sought to make the human condition better, often did so by embracing this principle over their religion's authority claims---or by redefining their faith along humanistic lines.
What is the place of reason and intelligence? Manifesto II states, "Reason and intelligence are the most effective instruments that humankind possesses. There is no substitute: neither faith nor passion suffices in itself." It is hard to argue against this point. Everything that makes life better comes by way of reason and intelligence. Whether it is medicine, psychotherapy, economics, or farming techniques, the driving force toward improvement is reason and intelligence. It is not religion.
In theory, humanism seeks to work all things together for the good of human beings. It seeks to expand individual freedom and foster the common good. It rejects dividing people into groups based on religion. Founded on a respect for the scientific method, it realizes that we are all descended from a common ancestor. It rejects any religion or ideology that seeks to dehumanize individuals. In short, it offers a positive, life-affirming view of humanity based on reason and science.
Both manifestos are obviously short statements of basic principles. It is not reasonable to assume that all possible contradictions are solved. After all, we have the Supreme Court to interpret our short statement of basic principles---the Constitution. The Christian Bible is much longer than the manifestos, and look at the contradictory theologies and principles that document engenders. Such criticism coming from theists is simply not credible.
Atheists and theists should reflect on the principles of both manifestos. Get a copy. It is good reading! In closing, I'll let Humanist Manifesto II speak for itself. "We urge recognition of the common humanity of all people. We further urge the use of reason and compassion to produce the kind of world we want---a world in which peace, prosperity, freedom, and happiness are widely shared."