Von Baer and Naturphilosophie: What Is the
Universal Direction of Development?

Was von Baer a Naturphilosoph? How shall we view his debate with Meckel and Oken over recapitulation? Did it represent a clash of two philosophies or a disagreement over the interpretation of a common framework? The subject has been discussed often and has given rise to a curious difference of opinion. Humanists (Cohen and Lovejoy) have detected an a prioristic Naturphilosoph where scientists (Oppenheimer, Meyer, and Severtsov) note a circumspect analyst of careful observations.22 The disagreement has an easy explanation (as facile as its simplistic categories but, perhaps, basically sound nonetheless). I doubt that many historians or philosophers have paid much attention to von Baer's descriptive embryology of the chick; they have concentrated on the scholia (especially the sixth, with all its cosmic pronouncements) and some popular essays on development. On the other hand, it is hard for scientists to ignore (though they should) the anachronistic influence of von Baer's triumph; for his laws, in refurbished evolutionary dress, are now more widely accepted than ever before, and his descriptions mark the beginning of modern embryology. It is then tempting to reason: if von Baer led us away from the fantasies of Oken's school, he must have opposed its philosophy, and, in the inductivist bias that most scientists impose upon their own history, he must have substituted the careful objective study of facts for the priority of speculation.

I doubt that such a controversy could have arisen unless both posi- tions were valid (though incomplete). Raikov has recently tried to re- solve this dilemma by arguing that von Baer's thinking moved "in two different planes . . . each with its own inner logic: the plane of the Naturphilosoph's conception of reality that rests on intuitions . . . and does not ask for proof, and the plane of scientific thought . . . that bases itself strongly upon facts and demands tangible proof" (1968, pp. 397–402). This complexity, indeed this inconsistency, surely exists in von Baer's thought, but I would prefer to render it as an internal clash of two biological philosophies.

Von Baer's empirical work unmistakably bears the stamp of Cuvier's thought. No one argued more incessantly than Cuvier that science should move from observation to theory, and shun the excesses of unsupported speculation. No one insisted more strongly than Cuvier that organs should be studied functionally as shapes designed for performance, not as ideal series distributed to meet the requirements of philosophical visions. (A laudatory biography of Cuvier, written by von Baer, was published posthumously in 1897.)