Three years later in 1844 Emerson published his Essays: Second Series , eight essays and one public lecture, the titles indicating the range of his interests: "The Poet," “Experience,” “Character,” “Manners,” “Gifts,” “Nature,” “Politics,” “Nominalist and Realist," and "New England Reformers.” “The Poet” contains the most comprehensive statement on Emerson's aesthetics and art. This philosophy of art has its premise in the Transcendental notion that the power of nature operates through all being, that it is being: "For we are not pans and barrows . . but children of the fire, made of it, and only the same divinity transmuted." Art and the products of art of every kind—poetry, sculpture, painting, and architecture—flow from the same unity at the root of all human experience. Emerson's aesthetics stress not the object of art but the force that creates the art object, or as he characterizes this process in relation to poetry: "it is not metres, but a metre-making argument that makes a poem." “The Poet” repeats anew the Emersonian dictum that nature is itself a symbol, and thus nature admits of being used symbolically in art. While Emerson does not accept in principle social progress as such, his philosophy emphasizes the progress of spirit, particularly when understood as development. This process he allies with the process of art: "Nature has a higher end . . ascension, or the passage of the soul into higher forms." The realm of art, ultimately for Emerson, is only an intermediary function, not an end itself: "Art is the path of the creator to his work." On this and every subject, Emerson reveals the humanism at the core of his philosophy, his human centric perspective that posits the creative principle above the created thing. "There is a higher work for Art than the arts," he argues in the essay "Art," and that work is the full creative expression of human being. Nature too has this “humanism,” to speak figuratively, in its creative process, as he writes in "The Method of Nature:" “The universe does not attract us until housed in an individual.” Most notable in "The Poet" is Emerson's call for an expressly American poetry and poet to do justice to the fact that “America is a poem in our eyes." What is required is a "genius . . with tyrannous eye, which knew the value of our incomparable materials” and can make use of the "barbarism and materialism of the times." Emerson would not meet Whitman for another decade, only after Whitman had sent him anonymously a copy of the first edition of Leaves of Grass , in which—indicative of Emerson's influence—Whitman self-consciously assumes the role of the required poet of America and asserts, like his unacknowledged mentor, that America herself is indeed a poem.