Who is Walt Whitman from On Photography and what is their importance?

Walt Whitman (1819-1892) was an American poet, journalist, and humanist. He was enormously influential in American culture and society and helped drive the transition between Transcendentalist and Realism. The text does not consider Whitman's contribution to poetry, but instead to social philosophy and cultural opinion, summarizing Whitman's stance as seeking unity-within-diversity. In brief, Sontag asserts that Whitman's desire was to weld the human species into a homogeneous whole by noting that the threads of commonality far outnumbered elements of dissent. The early chapters of the text are difficult to comprehend without a basic knowledge of Whitman's philosophy—which is not wholly available within the text itself. Whitman's early Realism is also considered as inspirational for an entire generation of emerging photographers.