Classical morphology concentrates more on the relations between forms than on the processes that might give rise to them. (eg. morphogenesis) (see also adaptation) Morphology studies the forms of organisms by juxtaposing them and evolving, from this juxtaposition, a standard of comparison. Since the work of Aristotle, who described variation according to "excess or defect," the most obvious standard of comparison has been that of homology.
Goethe seemed to be satisfied that his morphology was both a descriptive one and a causal one. (see explain / describe) For Goethe form -- at least in the sense of archetypal form -- is itself causal, so that form and law can be thought of as identical. It is in this sense that style, for Goethe, rests in the deepest foundations of knowledge, in the very essence of things, insofar as we are permitted to have knowledge of it through visible and tangible gestalts.
In his descriptions of his experience of the Urpflanze, Goethe set the tone for accounts of natural form as a meeting of the subjective and the objective in a sensuous intellectual intuition. (Ronald H. Brady, "Form and Cause in Goethe's Morphology," in Amrine, F. and Zucker, F. J. eds, Goethe and the Sciences: A Reappraisal, Boston Studies in the Philosophy of Science, vol 97, Dordrecht, 1987.)
But Goethe's concept of "genesis" is not a proto-Darwinian account. It is dynamic, not historical. The transformations by which the various parts of the plant, its sepals, petals, stamens, and so on, originated from the one common archetype, the leaf, is an ideal, not a real genesis. (E. Cassirer, The Problem of Knowledge, p149)
The comparative anatomist, if one part of the skeleton af an animal is given to him, claims to be able to reconstruct the whole animal, since every part is related to every other part and all are in a relation of constant interdependence. Systematic biology, as understood by Cuvier, was no mere device of classification. It presupposed a systematic correlation between the parts of an organism as well as a systematic relation between the single organism and the whole living world. The famous debate between Geoffroy St. Hilaire and Georges Cuvier was described as a debate between "morphology" and comparative anatomy, between and " abstract and transcendental" view and a commonsense teleology. (Russell, Form and Function.) It was also described as a debate between form determining function and function determining form.
According to Ernst Cassirer, the argument was a model of what Kant had described half a century before as two different modes of thought, two "interests" of reason. One of these had to do with unity and "homogeneity," (Geoffroy?) the other with multiplicity and "specification." (Cuvier?) According to Kant, controversies of this sort are incapable of being decided in such a way that one side is proved right or wrong. For Kant, there is no real opposition, for "When merely regulative principles are regarded as constitutive they can, as objective principles, well be in conflict with each other; but when they are taken simply as maxims there is no real opposition, only a different interest on the part of reason." (see Ernst Cassirer, The Problem of Knowledge, p.133)
In the nineteenth century, with the development of embryology, idealistic morphology began to pass into experimental morphology. While Goethe had been convinced that nature's secrets could never be wrung from her "with levers and screws," the ideal of the manipulation of nature (encheiresis naturae ) became central to a modern causal morphology, in which the researcher became an engineer of the organic whose aim was "to produce at will, through a knowledge of circumstances, as many as possible of the formative processes of plants." (Cassirer, p.159) (see mechanism / vitalism.)