The first Humanist Manifesto appeared in 1933, drafted mainly by a small group of philosophers, educators and Unitarian ministers, Roy Wood Sellars and Raymond Bragg chief among them, who wanted organized humanism to state plainly what it actually believed rather than let outsiders define it by what it rejected. Thirty four people signed that first document, describing the universe as self existing rather than created and treating traditional theism as an idea whose time, in their judgment, had passed. Even some of its own signers later questioned whether calling the document religious was accurate, since it explicitly set aside belief in a personal God.
Forty years of history separated the first Manifesto from the second, published in 1973, and the gap shows in the text. The earlier document's confident predictions about human progress had not all held up, and the 1973 statement dropped several of them while adding explicit commitments to human rights, reproductive freedom and international cooperation that the original had never addressed. It also drew a far larger list of signers, spanning philosophers, scientists and writers well beyond the small circle that had produced the first version.
Humanism and Its Aspirations, the third Manifesto, followed in 2003, considerably shorter than either predecessor and restating humanism's core commitments to reason, scientific inquiry and human flourishing in roughly a single page. Read together, the three documents trace not a fixed creed but an organization revising its own public statement of belief every few decades as its membership and its historical moment changed.