As a spokesman for "free religion", he asserted that Christianity, understood as based on the lordship of Christ, is no longer tenable. He rejected all dogma and reliance on Scriptures or creeds, teaching the truth is open to every individual. Abbot graduated from Harvard University and the Meadville Theological School. He served Unitarian churches in Dover, New Hampshire, and Toledo, Ohio, but his ministry proved controversial, and in 1868 New Hampshire's highest court ruled that the Dover, New Hampshire, First Unitarian Society of Christians' chosen minister was insufficiently "Christian" to serve his congregation. See Hale v. Everett, 53 N.H. 9. The Rev. Abbot had, it said, once preached that: In another sermon, the court noted, Rev. Abbot had even declared that "If Protestantism would include Mr. Abbot in this case," New Hampshire's highest court concluded, Hale v. Everett, 53 N.H. 9, 87-88. But opinions concerning Abbot diverged widely. Frederick Douglass, for example, praised Frank Abbot for doing "much to break the fetters of religious superstition, for which he is entitled to gratitude." Letter from Hon. Frederick Douglass to Rev. M.J. Savage, published in Farewell Dinner to Francis Ellingwood Abbot, on Retiring from the Editorship of "The Index" 48. Following the controversy in New Hampshire, Abbot left the ministry in 1868 to write, edit, and teach. Abbot's theological position was stated in Scientific Theism and The Way Out of Agnosticism. On the latter book Josiah Royce wrote an article so scathing that Abbot took it as an unfair attempt to destroy his reputation, and eventually responded publicly with Mr. Royce's Libel in which he sought redress from Royce's employer Harvard University. The debate moved to the pages of The Nation, where Charles Sanders Peirce took Abbot's side; William James and Joseph Bangs Warner, less so. In his 1903 obituary of Abbot, Peirce praised Abbot's philosophical work and love of truth, and wrote that, in the introduction to Scientific Theism, Abbot "put his finger unerringly upon the one great blunder of all modern philosophy." Abbot committed suicide in 1903 by taking sleeping pills at his wife's gravesite in Central Cemetery, Beverly, Massachusetts, on the 10th anniversary of her death.
