The potential for a single form to assume a number of different identities is an assumption underlying all of Arp's art. It corresponds to his working method, in which new shapes are "discovered" out of essential biomorphic forms. This assumption also corresponds to a philosophy which holds that all natural shapes are modifications of a few basic forms. This doctrine originated with Johann Wolfgang von Goethe, the eighteenth-century naturalist and artist who was one of the first to theorize about the nature of cellular growth. Goethe developed a view of the world based on dynamic change, in which process, growth, and development determine the identity of living organisms. Arp would have found a kinship of ideas with Goethe in, for example, the following passage:
“the organic parts of a plant—leaves and flowers, stamens and pistils, the great variety of covering tissues and whatever else strikes the senses—they are all identical organs which a succession of vegetative operations modifies and transforms beyond recognition.
The same organ can fan out into a compound leaf of the utmost complexity and contract to form the simplest stalk. Depending on circumstances, the same organ can develop into a flower bud or an infertile twig. The calyx, forcing its development, can become a corolla; and the corolla can undergo a regression in the direction of the calyx.”