Plato’s Embryology


In: Early Science and Medicine

Embryology was a subject that inspired great cross-disciplinary discussion in antiquity, and Plato’s Timaeus made an important contribution to this discussion, though Plato’s precise views have remained a matter of controversy, especially regarding three key questions pertaining to the generation and nature of the seed: whether there is a female seed; what the nature of seed is; and whether the seed contains a preformed human being. In this paper I argue that Plato’s positions on these three issues can be adequately determined, even if some other aspects of his theory cannot. In particular, it is argued that (i) Plato subscribes to the encephalo-myelogenic theory of seed, though he places particular emphasis on the soul being the true seed; (ii) Plato is a two-seed theorist, yet the female seed appears to make no contribution to reproduction; and (iii) Plato cannot be an advocate of preformationism.


  • 4

    For Alcmaeon, see Censorinus, De dei nat., 5.4 (= 24A13 DK) and 6.4 (= 24A14 DK). Hippon is sometimes described as having advanced a one-seed theory on the basis of 38A14 DK and Censorinus, De dei nat., 5.4, but Aëtius, Plac. phil. 5.5.3 (= 38A13 DK) attributes a theory of female seed to Hippon, though this seed does not contribute to the embryo as it is not conducted to the uterus, as in Herophilus. See Lesky, Zeugung, 28, and below on the female seed in Plato. For other references to the Pythagoreans, see Diogenes Laertius, Vit. phil.,8.28 (= 58B1 DK); Aëtius, Plac. phil.,5.5.1; and L. Zhmud, Pythagoras and the Early Pythagoreans (Oxford, 2012), 374–80. For Parmenides, see 28B18 DK; Aëtius, Plac. phil., 5.11.2 (= 28A54 DK); Censorinus, De dei nat., 5.4; 6.5; and 6.8 (the latter two passages are included in 28A54 DK). For Empedocles, see 31B63 DK. Cf. 31A81 DK. For Democritus, see Aëtius, Plac. phil., 5.5.1 (= 68A142 DK); Aristotle, GA, 764a6–11 Drossaart Lulofs (= 68A143 DK), and P.-M. Morel, “Aristote contra Démocrite. Sur l’embryon,” in L. Brisson, M.-H. Congourdeau and J.-L. Solère, eds., Porphyre. Sur la manière dont l’embryon reçoit l’âme (Paris, 2008), 43–57, at 46ff. For Epicurus, see Aëtius, Plac. phil., 5.5.1. For the Hippocratics, see especially Genit. and Nat. Puer. and Lonie, Hippocratic Treatises, 119–122. Also Mul. i, 8 (8.34,9f.; 8.56,21f.; and 8.62,20f. Littré) and Vict. i, 27 (144,4–5 Joly = 6.500,8f. Littré). For Diocles, see Fr. 42a/b in P.J. van der Eijk, Diocles of Carystus. A Collection of the Fragments with Translation and Commentary, 2 vols (Leiden, 2000–2001) = Fr. 172 in M. Wellmann, Die Fragmente der sikelischen Ärzte Akron, Philistion and des Diokles von Karystos (Berlin, 1901). Cf. Lesky, Zeugung, 30. For Herophilus, see Galen, De sem., 146,20–148,24 De Lacy (= 4.596,4- 598,7 Kühn and T60 von Staden) but also note 5 below. For Soranus, see Gyn., 1.4.93–98 Burguière et al. Regarding Galen, see especially De sem., 2.1 (144,4 - 160,23 De Lacy = 4.593,1–610,10 Kühn) and D. Nickel, Untersuchungen zur Embryologie Galens (Berlin, 1989), 40–49.

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  • 7

    Regarding Alcmaeon, see Aëtius, Plac. phil., 5.5.3, and Censorinus, De dei nat., 5.2 (both are included in 24A13 DK). Censorinus testifies that Alcmaeon actually opposed the encephalo-myelogenic theory, but as Lesky, Zeugung, 12, points out, this is simply due to his “ungenaue Sammelberichterstattung.” For Hippon, see Censorinus, De dei nat., 5.2 (= 38A12 DK); Aëtius, Plac. phil., 5.3.3 (= 38A13 DK). For more general evidence of Pythagoreans holding this view, see Diogenes Laertius, Vit. phil., 8.28 (= 58B1 DK) and the note ad loc (905A) in Lachenaud, Plutarque. There are traces of this view in the Hippocratic corpus at, e.g., Genit.,1.2 (44,10–20 Joly = 7.470,8–16 Littré). In general, see Lesky, Zeugung, 13–18; Lonie, Hippocratic Treatises, 101–3; von Staden, Herophilus, 288–96. For Diocles, see Fr. 41a-b van der Eijk.

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  • 13

    E.g., Lesky, Zeugung, 18–20; E. Lesky and J.H. Waszink, “Embryologie,” Reallexikon für Antike und Christentum 4 (1959), 1228–1244 at 1228; F.M. Cornford, Plato’s Cosmology: The Timaeus of Plato translated with a running Commentary (London, 1937), 295; van der Eijk, Diocles of Carystus, vol. 2, 92; M.-H. Congourdeau, L’embryon et son âme dans les sources grecques (Paris, 2007), 197.

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  • 16

    Cf. Theophilus Protospatharius, De corp. hum. fabr., 5.3.1 (189,5–8 Greenhill), where the brain is described as a “field” in which the rational soul is planted, either directly or by means of the spinal marrow.

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  • 21

    K. Praechter, “Platon Präformist?,” Philologus 83 (1928), 18–3 at 29n23.

  • 37

    Cf. Taylor, Commentary, 639.

  • 40

    Aetius, Plac. phil., 5.5.3 (= 38A13 DK) and see above note 5. According to Aetius, Plac. phil., 5.7.7 (= 38A14 DK) Hippon viewed the female contribution to consist only in τροφή. See Lesky, Zeugung, 27–28.

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  • 42

    For Hippon, see Aetius, Plac. phil., 5.7.7 (= 38A14 DK) with Lesky, Zeugung, 27–28.

  • 55

    Aëtius, Plac. phil. 5.3.6 (= 68A141 DK): Δημόκριτος ἀφ’ ὅλων τῶν σωμάτων καὶ τῶν κυριωτάτων μερῶν οἷον ὀστῶν σαρκῶν καὶ ἰνῶν [τὸ σπέρμα εἶναι]. There is some disagreement about whether the first καί is meant to be epexegetic (thus Perilli, “Democritus,” 171) or co-ordinative (H. De Ley, “Pangenesis versus panspermia. Democritean Notes on Aristotle’s Generation of Animals,” Hermes 108 [1980], 130–153 at 135–6). In the former case we have homoiomerous pangenesis, the results for the latter interpretation will depend on how one understands ἀφ’ ὅλων τῶν σωμάτων (which De Ley takes to refer to the organs).

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