What do its own followers disagree about?

About law, not creed: details of dress, rulings across the schools, historical questions. The six beliefs and the five pillars are not up for debate.

Whether to confront religion or coexist with it (the New Atheists against gentler humanists); whether morality is objective; whether free will exists; and politics — atheists span the spectrum from Marxists to libertarians, sharing only the one negative conclusion.

Chiefly three things: whether the God question is unanswerable in principle or merely unanswered; whether an agnostic may still practice a religion 'as if' — attending, praying tentatively, raising children in a tradition; and whether agnosticism really differs from atheism or is atheism being polite. Russell himself answered that last question both ways for different audiences.

Authority (pope, tradition, or Scripture alone); how the sacraments work; infant versus believer's baptism; predestination versus free will; women's ordination; sexuality and marriage; and how literally to read Genesis. The divisions of 1054 and 1517 remain unhealed, though the 20th-century ecumenical movement narrowed some gaps.

Who counts as a Jew (Orthodox and Conservative: matrilineal descent or conversion; Reform since 1983: either parent plus Jewish upbringing); women's place in ritual; how binding halakha is; conversion standards; and the religious meaning of the State of Israel. These disputes are open and recorded in each movement's own rulings.

Whether the Mahayana sutras are the Buddha's word; how essential rebirth and the unseen realms are (secular Buddhists set them aside, traditionalists object); whether full ordination for women should be restored in Theravada lands; and how far monks should engage in politics.

Whether ultimate reality is personal or beyond attributes; whether image worship is essential (most practice) or a corruption (the Arya Samaj); whether caste is dharma or a disease; which path — knowledge, devotion, or action — is highest; and today, whether Hindu identity should be political (Hindutva) or must not be.

Real disputes: the authority of the Dasam Granth; whether meat may be eaten; caste's stubborn survival in gurdwara and marriage patterns despite the Gurus' teaching; who counts as a Sikh; and the politics of a separate Sikh state (Khalistan).

Their disputes: funding religious schools, exemptions from general laws, religious symbols on public employees and in public buildings, and the deepest one — whether neutrality means keeping religion out of public space or admitting all religions even-handedly.

Whether morality is objective without God; how confrontational to be toward religion; whether humanism needs congregational forms; the movement’s politics and economics; and whether transhumanism is humanism’s future or a departure from it.

Markets versus redistribution (Hayek against Rawls); where free speech ends; religion's place in the public square; whether groups as well as individuals can hold rights; how much economic inequality liberty can tolerate; and abortion, immigration, and identity politics — all argued among liberals, loudly.

A great deal: pornography and sex work split the movement in the 1980s 'sex wars'; today feminists dispute quotas, the place of men in the movement, the priority of class versus sex, and — most sharply — how the category 'woman' relates to transgender identity.

Who belongs — citizenship or blood; the place of minorities and immigrants; whether the nation needs its own state or only autonomy; the role of religion; and whether pooling sovereignty, as in the European Union, betrays the nation or serves it. Tamir and Hazony, both defenders, disagree sharply on where its limits lie.