Paul Kurtz, who has died aged 86, was an American secular humanist and philosopher who devoted his life to debunking psychics and homoeopathic quacks, mystics, mediums, men of the cloth and other promoters of superstitions and religion; in their place he promoted “eupraxophy” — a science-based alternative that would provide moral and social structure without the need for God.
A prolific author, Kurtz in 1973 drafted what came to be known as Humanist Manifesto II, in which he updated a 1933 document by addressing issues that the earlier tract, which was largely a critique of religion, had failed to address, among them nuclear arms, population control, racism and sexism. The document was signed by 120 intellectuals including Andrei Sakharov, Francis Crick and the novelist Isaac Asimov. In its best-known dictum, it declared: “No deity will save us; we must save ourselves.”
In 1980, in response to the rise of the religious Right, Kurtz founded the journal Free Inquiry. In its first issue he warned that “the reappearance of dogmatic authoritarian religions’’ had become a threat to intellectual freedom, human rights and scientific progress. Most traditional religions, he observed, have their origins in pre-urban nomadic and agricultural societies of the past and are not appropriate to the modern age.
In Eupraxophy: Living Without Religion (1989) Kurtz envisioned a secular moral alternative that met some of the social needs served by religions without the supernaturalism or authoritarianism of traditional faiths.
He maintained that it was not only possible but easy to live a good life without religion . In a revised Humanist Manifesto 2000, endorsed by, among others, nine Nobel Prize winning scientists, Kurtz called on humankind to form a planetary system of government, including a World Parliament elected on the basis of population, a transnational environmental monitoring agency and a transnational system of taxation.
Ironically, though, secular humanism has proved just as disputatious and faction-prone as the religions it seeks to debunk, and Kurtz’s career was marked by a series of fallings-out with his fellow non-believers.
In 1978 he parted company, amid some acrimony, with the American Humanist Association, whose journal, Humanist, he had edited, and went on to found a series of organisations of his own, including the Committee for the Scientific Investigation of Claims of the Paranormal (which became the Committee for Skeptical Inquiry), the Council for Secular Humanism, and the Centre for Inquiry.
But in 2010, after a series of disagreements, Kurtz resigned from the organisations he had founded saying that he disapproved of their “angry atheism”.
Paul Winter Kurtz was born in Newark, New Jersey, on December 21 1925 into a Jewish family of “intellectual freethinkers”. His father was a restaurateur. Paul left New York University to enlist in the US Army during the Second World War, fought in the Battle of the Bulge and entered the concentration camps at Buchenwald and Dachau shortly after their liberation.
Returning to New York University, after graduation he took a doctorate in Philosophy at Columbia University, then taught the subject at several universities before moving, in 1965, to the State University of New York at Buffalo, where he became a Professor of Philosophy, remaining until his retirement.
Active in the Humanist movement from the 1950s, in 1969 Kurtz created Prometheus Books, a publishing house that released works critical of religion that other publishers would not touch. His Committee for Skeptical Inquiry published the Skeptical Inquirer to combat “pseudoscience”, including UFO sightings, the paranormal and homoeopathy. In 2010 Kurtz founded a new Institute for Science and Human Values and the journal The Human Prospect.
His first marriage ended in divorce. He is survived by his second wife, Claudine, and by a son and three daughters.

Paul Kurtz, born December 21 1925, died October 20 2012