What in Reinke's case came about almost unperceived, Driesch did with full consciousness and intention, following the necessity laid upon him by his own gradual personal development and by his consistent, tenacious prosecution of the problem. The acuteness of his thinking, the concentration of his endeavours [pg 262] through long years, his comprehensive knowledge and mastery of the material, the deep logicalness and consistent evolution of his “standpoints,” and his philosophical and theoretical grasp of the subject make him probably the most instructive type, indeed, we may almost say, the very incarnation of the whole disputed question. In 1891 he published his “Mathematisch—mechanische Betrachtung morphologischer Probleme der Biologie,” the work in which he first touched the depths of the problem. It is directed chiefly against the merely “historical” methods in biology, used by the current schools in the form of Darwinism. Darwinism and the Theory of Descent have been so far nothing more than “galleries of ancestors,” and the science ranged under their banner is only descriptive, not explanatory. Instead of setting up contingent theories we must form a “conception” of the internal necessity, inherent in the substratum itself, in accordance with which the forms of life have found expression—a necessity corresponding to that which conditions the form-development of the crystal.

Experimental investigations and discoveries, and further reflection, resulted, in 1892, in his “Entwicklungsmechanische Studien,” and led him to insist on the need for what the title of his next year's work calls “Biologie als selbstÄndige Grundwissenschaft.” In this work two important points are emphasised. The first is, that biology must certainly strive after precision, [pg 263] but that this precision consists not in subordination to, but in co-ordination with physics. Biology must rank side by side with physics as an “independent fundamental science,” and that in the form of tectonic. And the second point is, that the teleological point of view must take its place beside the causal. Only by recognising both can biology become a complete science.

In the “Analytische Theorie der organischen Entwicklung” (1894) Driesch picks up the thread where he dropped it in the book before, and spins it farther, “traversing” his previous theoretical and experimental results. In this work the author still strives to remain within the frame of the tectonic and machine-theory, but the edges are already showing signs of giving way. Life, he says, is a mechanism based upon a given structure (it is however a machine which is constantly modifying and developing itself). Ontogenesis98 is a strictly causal nexus, but following “a natural law the workings of which are entirely enigmatical” (with Wigand). Causality fulfils itself through “liberations,” that is to say, cause and effect are not quantitatively equivalent; and all effect is, notwithstanding its causal conditioning, something absolutely new and not to be calculated from the cause, so that there can be no question [pg 264] of mechanism in the strict sense. And the whole is directed by purpose.99 The vital processes compel us to admit that it seems “as if intelligence determined quality and order.” Driesch still tries to reconcile causes and purposes as different “modes of regarding things,” but this device he afterwards abandons. We cannot penetrate to the nature of things either by the causal or by the teleological method. But they are—as Kant maintained—two modes of looking at things, both of which are postulates of our capacity for knowing. Each must stand by itself, and neither can have its sequence disturbed by the interpolation of pieces from the other. In the domain of the causal there can be no teleological explanation, and conversely; one might as well seek for an optical explanation of the synthesis of water; but both are true in their own place. The Madonna della Sedia, looked at microscopically, is a mass of blots, looked at macroscopically it is a picture. And it “is” both of these.

Driesch's conclusions continue to advance, led steadily onwards by his experimental studies. In the “Maschinentheorie des Lebens,”100 he attacks his own earlier theories with praiseworthy determination, and remorselessly pursues them to the monstrous conclusions to which they lead, and shows that they necessarily perish [pg 265] because of these. He had previously declared, at first emphatically, later with hesitation (we have already seen why), that every single vital process is of a physico-chemical kind, on the basis of a given “structure” of living beings. But now he considers the living organism as itself a result of vital processes—that is, of development. If this also is to be explained mechanically (as physico-chemical processes based on material structure), then the ovum must possess in parvo this infinitely fine structure, by virtue of which it fulfils its own physiological processes of maintenance, and also becomes the efficient cause of the subsequent development. It must bear the type of the individual and of the species, as a rudiment (or primordium) within its own structure. Every specific type must, however, according to the theory of descent, be derived through an endless process of evolution, by gradual stages, from some primitive organism. Just as in the mechanical becoming of the individual organism, so the primitive protovum must also be extraordinarily intricate and complex in its organisation if it is to give rise to all the processes of evolution and development involved in the succeeding ontogenies, phylogenies, regenerations, and so forth. This is a necessary conclusion if the machine-theory be correct, and if we refuse to admit that vital phenomena are governed by specific laws. This consequence is monstrous, and the theory of the tectonists therefore false. But if it be false, what then?