Secular Humanism is the most prominent branch of Humanism and being that it is grounded in secularphilosophy by rejecting supernaturalism, it fundamentally conflicts with religious belief. Secularism may or may not be opposed to religion per se, but as a social movement it is especially concerned with religious law, whereby a strict doctrine is imposed upon the citizenry dismissing the concept and practice of freedom of religion. Regarding political matters, Secular Humanism seeks to keep the government separate from the influence of any particular religion in order that rules developed under secularism may be universally applied.
Secular Humanism can be (over) simplified thus:
Humans matter and can solve human problems
Science, free speech, rational thought, democracy and freedom in the arts go together
There is no supernatural
There are now nine Humanist Manifestos and Declarations:
The two individuals who have done the most to promote Secular Humanism in the 20th Century are Dr. Paul Kurtz and Gene Roddenberry. Secular Humanism often finds itself in conflict with Christian fundamentalism, especially over the issue of state involvement in religion. Secular Humanists tend to see Christian fundamentalists as superstitious and regressive, while Christian fundamentalists tend to see Secular Humanists as the work of Satan as a means to direct society away from God. Secular Humanists counter that religious factionism will never be a solution to human problems, and claim Humanist principles are adequate to address the same issues as religious principles (for example, ethics and morals).