The distinctive New Thought practice, usually called treatment or affirmative prayer, is not petition in the ordinary sense, asking God for an outcome, but a disciplined redirection of the practitioner's own thought toward the truth the tradition holds already to be the case: that the person treated is, in Unity's phrasing, already whole, complete and perfect as an expression of the one Mind, whatever their symptoms currently suggest. A practitioner or minister trained in this method holds a specific mental and spoken affirmation for a set period, on the premise that thought operating in line with divine Mind produces a corresponding change in physical or material condition.
The claim that thought and prayer can resolve physical illness has drawn sustained theological and medical criticism, the latter from clinicians concerned that reliance on affirmation in place of treatment can delay necessary care. New Thought bodies have responded differently: Unity, Religious Science and Divine Science all now generally present treatment as a complement to medical care rather than a substitute for it, a shift from the movement's earlier decades when Christian Science's harder line against medicine cast a shadow over New Thought's own, generally milder, position.
The teaching's wider cultural reach outran its founding denominations. Popular self-help and prosperity literature from the twentieth century onward, including material with no denominational tie at all, draws directly on the New Thought claim that consciousness determines circumstance, making the doctrine one of the few pieces of specifically American religious metaphysics to pass into secular self-improvement culture largely intact.