Forms, Souls, and Embryos

Neoplatonists on Human Reproduction

James Wilberding

• Publisher: Routledge
• Year: 2016
• ISBN:
  9781317355243
• Edition: 1
• Topic: History
• Subtopic: Ancient History
• Index: History

Forms, Souls, and Embryos allows readers coming from different backgrounds to appreciate the depth and originality with which the Neoplatonists engaged with and responded to a number of philosophical questions central to human reproduction, including: What is the causal explanation of the embryo's formation? How and to what extent are Platonic Forms involved? In what sense is a fetus 'alive, ' and when does it become a human being? Where does the embryo's soul come from, and how is it connected to its body? This is the first full-length study in English of this fascinating subject, and is a must-read for anyone interested in Neoplatonism or the history of medicine and embryology.

1
The Embryological Background

The aim of this chapter is to examine Plato’s remarks pertaining to embryology, which are almost entirely contained in the Timaeus, and to set out his views in as much detail as the texts permit. In this way, when we turn to the Neoplatonists we will be in a better position to evaluate to what extent their theories are fair representations, or at least fair developments, of Plato’s theory. This examination of Plato will be facilitated by a brief overview of four key issues in ancient embryology, namely the three major issues in spermatogenesis¹ – the number of seeds involved in reproduction, the corporeal origin of the seed, the manner in which the offspring is present in the seed – along with the moment of animation of the offspring. As we shall see, these are all issues that were widely discussed by both philosophers and physicians in antiquity, and so we can reasonably expect Plato to have been familiar with them and to be addressing them in the Timaeus (or else to be consciously avoiding them). To be sure, these four issues are far from exhausting the scope of ancient embryology. The list of embryological questions collected by Aëtius gives a sense of some of the issues being left out of this overview, e.g. how twins are formed, how the offspring’s sex is determined, and how to account for deformities and (lack of) resemblance.² Although we shall see that Neoplatonists did concern themselves with some of these other issues, their interest in them was limited and Plato does not incorporate them into his account at all. We can therefore leave these other questions aside for now. In the next chapter we shall have the opportunity to explore a further key issue in ancient embryology, namely the causal factors involved in embryogenesis, but since this is again a topic on which Plato has little to offer its discussion may be postponed.

General Background: Four Key Issues in Ancient Embryology

The first issue concerns the number of seeds involved in normal biological reproduction. On one theory the male is the sole supplier of seed. References to such a theory in Aeschylus and Euripides suggest that it was widespread among early Greeks, and we have evidence that it was advanced by a number of philosophers, including Anaxagoras, Diogenes of Apollonia, Aristotle, and the Stoics.³ An obvious difficulty connected to the one-seed theory is how to account for maternal resemblance, which the alternative two-seed theory could easily explain. The view that both the male and the female emitted seed found a wide-ranging scope of acceptance among philosophers – Alcmaeon, Hippon, and other Pythagoreans, Parmenides, Empedocles, Democritus, Epicurus – and especially among ancient physicians: the Hippocratics, Diocles, Herophilus, Soranus, and Galen.⁴ One difficulty of the two-seed theory that its proponents must address is why the male is required for reproduction, seeing as the female already has a seed at hand. A common (but not universal) response to this difficulty was to posit that the female seed is either inferior or else completely inactive.⁵

The second issue relates to the corporeal origin of the seed, and there were three standard responses to this issue. The oldest was the so-called encephalo-myelogenic theory, which states that the seed comes from the brain and/or the marrow.⁶ This was held by Pythagoreans such as Alcmaeon and Hippon, and traces of this theory can still be found in the Hippocratic corpus and in Diocles.⁷ This theory eventually gave way to the theory of pangenesis, which has the seed being drawn from the entire body in order to better account for the family resemblances, as was advanced by Anaxagoras, Democritus, Hippocratic authors, and Epicurus.⁸ The third and final position to emerge was the hematogenous theory, which derives seed from the concoction of blood. This appears to be advanced by Parmenides and Diogenes of Apollonia and is taken up and developed in much greater detail by Aristotle and later physicians such as Erasistratus, Herophilus, and Galen.⁹

The next issue that was commonly discussed concerned the manner of the offspring’s physical presence in the seed. Preformationists held that the body of the offspring exists pre-formed in the seed, whereas epigenesists (e.g. Aristotle and Galen¹⁰) argued that the parts are formed successively after conception. Some form of preformationism necessarily follows from pangenesis, where the exact type of preformationism to follow will depend on the kind of parts being supplied and whether they are pre-arranged into an organic unity (though preformationism would seem to be at least conceptually possible even in the absence of pangenesis). It is helpful to distinguish between three varieties of preformationism, which I shall call homoiomerous preformationism, anhomoiomerous preformationism and homuncular preformationism. The first two maintain respectively that the homoiomerous parts such as the humors or flesh and bone and the anhomoiomerous parts such as the head, hands and organs pre-exist in the seed but are not yet organized into a unified whole, while according to homuncular preformationism the seed already contains a unified organic living thing. It is not clear that anyone in antiquity actually intended to defend homuncular preformationism, though some remarks come close to suggesting it.¹¹

In addition to accounting for the formation of the body, the manner and source of the offspring’s soul became an increasingly important topic of philosophical embryology, a topic that was often broached by asking the question of when the seed (or embryo or offspring) becomes a living thing (ζῷον).¹² The moment of animation was commonly identified either as conception, in which case the soul was often seen as being provided in some way by the seed(s),¹³ or birth, in which case the soul was generally held to come from outside,¹⁴ though there are exceptions in both cases – the middle Platonist Numenius, for example, is reported to have thought that the soul comes in from outside at the moment of conception,¹⁵ and the Stoics pointed to birth as the moment of animation but would not agree that this animation involves a soul coming in from outside.¹⁶ The development of more refined psychological theories permitted a more gradualist approach to animation. Thus, it is Aristotle who first gives a clear and nuanced exposition of these issues. On his account, the male seed provides for the vegetative and sensitive soul, which successively comes to exist in the embryo, with the rational soul coming in from the outside at some undetermined point.¹⁷ Likewise, Galen advances a similarly gradualist account of animation in which the various powers of soul emerge as the relevant organs are formed.¹⁸

Embryology in Plato

Plato’s views on these issues have been the subject of various interpretations over the years. Remarks that give some indications on Plato’s embryological views can be found scattered throughout the dialogues, but it is in the Timaeus that we find Plato’s most considered views on the issue, with the two most critical passages appearing at 73b1–e1 and at the end of the dialogue in 91a4–d5.

The first passage is concerned with the nature of the seed and its origin in the body:

As for flesh and bones and things of that nature, this is how it is. The starting point for all these was the formation of marrow. For life’s chains, as long the soul remains bound to the body, are bound within the marrow, giving roots for the mortal race. The marrow itself came to be out of other things. For the god isolated from their respective kinds those primary triangles which were undistorted and smooth and hence, owing to their exactness, were particularly well suited to make up fire, water, air and earth. He mixed them together in the right proportions, and from them made the marrow, a πανσπερμíα contrived for every mortal kind. Next, he implanted in the marrow the various types of soul and bound them fast in it. And in making his initial distribution, he proceeded immediately to divide the marrow into the number and kinds of shapes that matched the number and kinds of shapes that the types of soul were to possess, type by type. He then proceeded to mold the ‘field,’ as it were, that was to receive the divine seed, making it round, and called this portion of the marrow, ‘brain.’ Each living thing was at its completion to have a head to function as a container for this marrow. That, however, which was to hold fast the remaining, mortal part of the soul, he divided into shapes that were at once round and elongated, all of which he named ‘marrow.’ And from these as from anchors he put out bonds to secure the whole soul and so he proceeded to construct our bodies all around this marrow, beginning with the formation of solid bone as a covering for the whole of it.

(Plato Timaeus, Zeyl translation slightly revised, 73b1–e1)

This passage has been pointed to as evidence that Plato is an encephalo-myelogenic theorist,¹⁹ and there is certainly a good deal of truth in this attribution. For here Plato describes the marrow, which is constituted of the most perfect triangles, as the starting point of the formation of all the other parts. More importantly, he labels the marrow a πανσπερμíα, which usually gets translated as a kind of seed.²⁰ But a closer look at the details of this passage reveals that Plato appears to be employing the term πανσπερμíα in the sense of a receptacle or a seedbed rather than a seed itself.²¹ For he goes on to say that the Demiurge ‘implants’ (φυτεύων) the various types of soul in the marrow. Moreover, the concentration of marrow that constitutes the brain is called a ‘field’ (ἄρoυραν), and this field is again said not to be a seed but to ‘receive the divine seed,’ which is the immortal (rational) soul.²² In short, the marrow appears to be introduced not as a universal seed but as a universal seedbed; that is, a receptacle for all kinds of seeds. The true seed appears to be the soul, though Plato does not explain here or elsewhere in the Timaeus how exactly the soul is supposed to execute the essential seminal function of forming the embryo. Moreover, Plato explicitly refers only to the rational soul as a seed, but the larger implication of the passage appears to be that all three kinds of soul are in fact seeds, since otherwise the marrow could not be called a universal seedbed ‘for every mortal kind.’²³ To be sure, Plato does subsequently refer to the marrow as a ‘seed’ (σπέρμα), which would seem to be in tension with what he says here, but the tension is easily alleviated by acknowledging that in the remaining part of the Timaeus Plato is conceiving of marrow that is already in possession of soul.²⁴ As we shall see below, Neoplatonists and commentators picked up on and drew their own conclusions from this terminological discrepancy.²⁵

The second and third issues explored in our overview are best approached by considering the second and the major embryological passage in the Timaeus:

For the fluids we consume there is a channel, and where it receives the fluids going through the lungs over the kidneys to the bladder and expels them under pressure from air, they bored a channel to the compacted marrow that runs from the head down the neck and over the spine – the marrow, that is, that we called ‘seed’ above. This marrow, seeing that it is ensouled and has be...

Table of contents

• Cover
• Title
• Copyright
• Dedication
• CONTENTS
• Acknowledgments
• Introduction
• 1 The Embryological Background
• 2 The Metaphysical Background
• 3 Neoplatonic Embryology: The Core Theory
• 4 The Formation and Animation of the Embryo
• 5 The Problem of Teratogenesis
• Epilogue
• Bibliography
• Index locorum
• Subject index