Karen Detlefsen

This paper has two parts: In the first part, I give a general survey of the various reasons 17th and 18th century life scientists and metaphysicians endorsed the theory of pre-existence according to which God created all living beings at the creation of the universe, and no living beings are ever naturally generated anew. These reasons generally fall into three categories. The first category is theological. For example, many had the desire to account for how all humans are stained by original sin (we were all there). As another example of a theological motivation, some take the organism as an obvious starting point for a teleological argument for God’s existence, and this staring point is sometimes developed into a full-blown theory of pre-existence. The second category could be thought of as non-theological metaphysical, and paramount here is the desire to deal with the metaphysical problem of individuation. So, for example, Leibniz embraces a version of hylomorphism in order to overcome difficulties with Descartes’ theory of material substance, including the difficulty of how to account for enduring material individuals, and Leibniz’s hylomorphism is closely linked with his embrace of pre-existence. The third category might be termed “biological”, and one example of such a concern is how to explain the organic unity of living beings where the whole seems to ontologically precede the parts. This is frequently translated into a temporal priority of whole to parts, and thus pre-existence is posited. Of course, many natural philosophers of the early modern period embrace pre-existence for more than one reason, but in general, these are the three classes of motivations one might have for embracing the theory. In the second part of the paper I examine in detail one argument that appears in the work of Malebranche. On the face of it, this argument seems to be a biological one, specifically the biological or organic holism argument mentioned above. But upon closer examination, I shall argue, Malebranche’s reasons for endorsing pre-existence bring together several of the arguments discussed in the first part of the paper. I conclude with some considerations about what we can learn about Malebranche as a natural philosopher from his motivations for holding the pre-existence doctrine of generation.

In this paper, I consider Descartes’ Sixth Meditation dropsy passage on the difference between the human body considered in itself and the human composite of mind and body. I do so as a way of illuminating some features of Descartes’ broader thinking about teleology, including the role of teleological explanations in physiology. I use the writings on teleology of some ancient authors for the conceptual (but not historical) help they can provide in helping us to think about the Sixth Meditation passage. From this, I draw several points, most notably that the Sixth Meditation passage is primarily concerned with the natures of body and composites, and that the issue of teleological explanation is derivative of this primary interest. So, we – and Descartes – must come to terms with what he takes the nature of the composite to be such that it has an intrinsic end-referred nature which grounds teleological explanations. I consider three possibilities: the human composite is a third type of substance – a hylomorphic substance; there is a sort of “satisfaction” relationship between mind and body (each of which retains its own distinct nature in the composite) such that the mind confers teleological value on the body; and there is a sort of “satisfaction” relationship between mind and body (each of which retains its own distinct nature in the composite) such that the mind recognizes teleological value in the body. None of these interpretations is without problems. So in the concluding section, I sketch a program for future research, specifically, trying to render Descartes’ teleological thinking consistent by distinguishing between the metaphysical natures of things (the concern of his Sixth Meditation passage) and the physical natures of things (his concern in his physiological writings).

According to Margaret Cavendish the entire natural world is essentially rational such that everything thinks in some way or another. In this paper, I examine why Cavendish would believe that the natural world is ubiquitously rational, arguing against the usual account, which holds that she does so in order to account for the orderly production of very complex phenomena (e.g. living beings) given the limits of the mechanical philosophy. Rather, I argue, she attributes ubiquitous rationality to the natural world in order to ground a theory of the ubiquitous freedom of nature, which in turn accounts for both the world's orderly and disorderly behavior.

The theories of pre-existence and epigenesis are typically taken to be opposing theories of generation in the seventeenth and eighteenth centuries. One can be a pre-existence theorist only if one does not espouse epigenesis and vice versa. It has also been recognized, however, that the line between pre-existence and epigenesis in the nineteenth century, at least, is considerably less sharp and clear than it was in earlier centuries. The debate (1759-1777) between Albrecht von Haller and Caspar Friedrich Wolff on their theories of generation is usually taken to be a debate between a pre-existence theorist and an epigeneticist, and the supposed fact that these two theories of generation are mutually exclusive explains (so the story goes) the divide between Haller and Wolff. However, it’s not clear that Haller endorsed an especially robust form of pre-existence, and nor is it clear that Wolff’s theory of generation -- once he considered it carefully -- is clear epigenetic. Rather, Haller’s theory of generation is marked by traces of epigensis and Wolff’s theory has elements of pre-existence theory. This is not to say that their theories of generation are basically the same, but the debate between the two ought not to be framed in terms of pre-existence versus epigenesis. Their points of difference must be explained in some other way. In this way, their controversy bears characteristics of similar disputes over generation in the nineteenth century more than it resembles those in the seventeenth century. In this paper, I argue that (a) Haller’s and Wolff’s theories both blend elements from pre-existence and epigenesis; (b) but there are still deeply-rooted differences between the two generation theories; (c) one source of these differences is that Haller and Wolff have divergent conceptions of what an adequate explanation is; (d) we can see that they have different conceptions of what constitutes an adequate explanation by paying heed to their evaluations of Descartes’ epistemology and methodology in his theory of generation (such as it is); and (e) this shows that one of the main differences between Haller’s generation theory and that of Wolff is the degree to which each thinks we need to (and indeed can) explain the nature of the causes -- both efficient and final -- at play during the formation of organic beings.