There is no clergy in Islam in the sacramental sense: no one is ordained, no one confers grace, and no rite requires a specialist. Any adult who knows the words can lead prayer, marry a couple, wash a corpse, or accept a conversion. What Islam has instead is expertise — the ulama, who are consulted the way one consults a lawyer, and who have no power to bind anyone's conscience. In practice, of course, state religious ministries, licensing regimes and prayer-leader appointments have reintroduced hierarchy through the back door, and Shia Islam, with its ranked jurists and its requirement to follow a living marja', has a good deal more structure than the theory suggests. But the theory is doing real work: it is why there is no Muslim confession and no Muslim excommunication that anyone is obliged to accept.