Phineas Parkhurst Quimby (1802-66), American mental healer, who founded the New Thought movement, a religio-metaphysical healing group. Originally a student of mesmerism and practitioner of hypnosis, Quimby subsequently claimed that he could heal by mere suggestion. Quimby believed that illness originated in the mind and was a consequence of erroneous beliefs. He taught that the receptive mind, open to God's wisdom, could conquer any sickness. One of his patients and, for a time, a disciple was Mary Baker Eddy, the founder of Christian Science. Quimby became a controversial figure when Eddy rejected his healing method on the grounds that healing came through the power of God, not the human mind.