Art historian Traci Lee Costa has argued that a "reductive" emphasis on Bannister's biography has taken attention away from scholarly analysis of his artwork. In the lecture "The Artist and His Critics" given to the Ann Eliza Club on April 15, 1886, and published afterward, Bannister spelled out his belief that making art is a highly spiritual practice—the pinnacle of human achievement. In its nearly religious approach and focus on subjective representations of nature, Bannister's philosophy has been compared to both German Idealism and American Transcendentalism. In his lecture, Bannister made explicit reference to the works of American Transcendentalist Washington Allston. Bannister's friend George W. Whitaker even referred to him as "The Idealist" in a 1914 article "Reminiscences of Providence Artists."