Oken's Classification of Animals by
Linear Addition of Organs

Oken renders all of nature with the aid of his philosophical principles. The unity of law and structure dictates that the entire mineral kingdom assume the same form: the crystal. The earth itself is a giant crystal, a rhomboidal dodecahedron. Its strata are cleavages, its mountains are edges: "The land cannot therefore have an equal elevation everywhere above the water, because the crystal consists of edges, angles, and surfaces or sides. The mountain tops are probably the angles, the mountain ridges or chains the edges, and plains the lateral surfaces of the crystal" (1847, p. 123).

Yet Oken's most pervasive principle is his own version of the single developmental tendency: all development begins with a primal zero and progresses to complexity by the successive addition of organs in a determined sequence. This law holds for all developmental processes: human ontogeny, the historical sequence of species, the evolution of the earth itself: "If we take a retrospective glance at the development of the planet, we find that it commenced with the simplest actions, and then assumed a more elevated character by gradually drawing together several actions and letting them work in common" (p. 178).

The sequence of additions follows Oken's ordering of the four Greek elements. Translated into the organs of animals, this sequence includes:

1. Earth processes—nutrition.
2. Water processes—digestion.
3. Air processes—respiration.
4. Aether (fire) processes—motion.

Man contains all organs within himself; thus he represents the entire world; "in the profoundest, truest sense . . . a microcosm" (p. 202). "Man is the summit, the crown of nature's development, and must comprehend everything that has preceded him . . . In a word, Man must represent the whole world in miniature" (p. 12). All lower animals, as imperfect or incomplete humans, contain fewer than the total set of organs. "The animal kingdom," wrote Oken in his most famous pronouncement, "is only a dismemberment of the highest animal, i.e. of Man" (p. 494). The position of any animal upon the single chain of classification depends upon the number of organs it possesses: "Animals are gradually perfected, entirely like the single animal body, by adding organ unto organ . . . An animal, which e.g. lived only as an intestine, would be, doubtless inferior to one which with the intestine were to combine a skin" (p. 494).

From this simple (if fanciful) premise, Oken's system of classifica-