Francis Ellingwood Abbot (November 6, 1836 – October 23, 1903)[1] was an American philosopher[2] and theologian who sought to reconstruct theology in accordance with the scientific method.

[3] His lifelong romance with his wife, Katharine Fearing Loring, forms the subject of If Ever Two Were One, a collection of his correspondence and diary entries.

M.J. Savage (June 15, 1880), published in Farewell Dinner to Francis Ellingwood Abbot, on Retiring from the Editorship of "The Index" 48 (George H. Ellis, 1880).

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.

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.