Parallelism
"Man stands, by virtue of his powers, a solitary ego within a universe of energy; a witness, a participant; and, by virtue of his powers a co-creator, -- his creations are but parallels of himself."
-Louis Sullivan
Sullivan believed that the artist is a force that draws inspiration from nature and gives formless things a form. This process transforms rigid geometries into awakened shapes that bring the vitality of nature into human environments.
This awakening process is based on the growth of a plant. Sullivan referenced books like Gray's School and Field Book of Botany, which described plant growth as a linear process beginning at the sprouting of a seed. The image to the left shows Sullivan's drawing of the seed germ motif. This sprouting motion became the basis for how Sullivan drew the awakening motion of shape.
For Sullivan, Parallelism is about both parallel shapes in a composition and the parallels between art and science, natural instinct and human intellect. He believed that art and science should support each other with art humanizing science and science energizing art. In his essay Study on Inspiration, Sullivan says "When the soul of nature and the soul of man sing in cadence they give voice to ravishing expressions, unforgettable ecstasies.... Creative force is born of this alliance of two infinites, nature's boundless reality, the heart's boundless illusion."
In composition, parallel forms are useful for Sullivan because they allow him to repeat organic forms so that they form a pattern with recognizable order, marrying the inorganic to the organic. The image to the left is a plate from A System of Architectural Ornament and it shows how parallel axes can create a unified composition.
The degree to which Sullivan uses parallel forms varies between his compositions. Sometimes he opts to use only awakened geometric shapes to order his compositions and a few compositions only use layered axes. The example to the left even uses what Sullivan calls "non-euclidian" symmetry, or a rhythm of similar elements. The vast majority, however, use some combination of both awakened shapes and axial organization to create the entire form.
The reason for this diversity seems to not be rooted in Sullivan's theories of design but rather the practical need for different methods of organization for different types of ornamentation. However, in all of Sullivan's compositions the underlying principle of geometric organization still remains whether it is through geometric shapes or axes.