Across their different decades and drafting committees, the humanist manifestos and the Amsterdam Declaration converge on a small set of recurring commitments: that claims about the world should be grounded in observation, reason and science rather than revelation, that ethical values arise from human experience and need rather than from divine command, that human dignity and human rights hold regardless of religious belief, and that religious and secular institutions should remain constitutionally separate so that no single creed governs public life. Later revisions, particularly Humanist Manifesto III, tend to state these commitments more briefly and with fewer specific policy positions than Humanist Manifesto II, which had ventured detailed stances on nuclear disarmament, population control and economic planning that dated quickly.
Not every organization in the wider humanist and secular movement has adopted a manifesto of this kind. The Ethical Culture movement, founded by Felix Adler in New York in 1876, predates the manifesto tradition by decades and has generally declined to state its position as a fixed creedal document at all, holding instead to Adler's own formula, deed before creed, that right ethical action matters more than agreement on a stated philosophical position, and that Ethical Culture societies should remain open to theists and nontheists alike who share a commitment to ethical practice. Where the American Humanist Association and Humanists International each anchor their identity partly in a signed statement of belief, Ethical Culture's founding move was to decline exactly that kind of statement, a difference of method that runs deeper than any single clause either side might dispute.