Aristotle on genera, species, and ?the more and the less?

Ernst Mayr, Populations, Species, and Evolution (Cambridge, Mass.: Harvard University Press, 1963), p. 4. Similarly Theodosius Dobzhansky comments in Genetics of the Evolutionary Process (New York: Columbia University Press, 1970), p. 351: ?Platonic and Aristotelian doctrines of archetypes or essences have strongly influenced medieval as well as some modern philosophies?; and G. G. Simpson says in Principles of Animal Taxonomy (New York: Columbia University Press, 1961), p. 46: ?Typology stems from Plato and his sources and came into taxonomy along with Aristotelian, Neo-Platonic, Scholastic and Thomist philosophy and logic.? Cf. David Hull, ?The Metaphysics of Evolution?, Brit. J. Hist. Sci., 3, no. 12 (1967), 309?337; and M. T. Ghiselin, The Triumph of the Darwinian Method (Berkeley: University of California Press, 1969), pp. 50?52.

D'Arcy W. Thompson, On Growth and Form, abridged ed. by J. T. Bonner (Cambridge: Cambridge University Press, 1971), p. 274.

Space limitations preclude my here entering into the debate about the chronological relationship between the Metaphysics and the various biological treatises. I disagree with the dominant view of D'Arcy W. Thompson's preface to his translation of the Historia Animalium for Oxford; H. D. P. Lee, ?Place Names and the Date of Aristotle's Biological Works?, Class Quart. 42 (1948), 61?67; John Herman Randall, Jr., Aristotle (New York: Columbia University Press, 1960), chap. 11; H. D. Hantz, The Biological Motivation in Aristotle (New York: published privately, 1939); and Marjorie Grene, A Portrait of Aristotle (Chicago: University of Chicago Press, 1963), Bibliographical Note, pp. 254?255; all of whom maintain that the most mature aspects of Aristotle's Metaphysics must be based on his biological research. My own position (which can be found in my unpublished dissertation, ?The Interaction between Aristotle's Metaphysics and Hist Biological Works, Univeristy of Toronto, 1978, chap. 1) agrees with Geoffrey Lloyd's assessment that while ?the particular answers he gave to those questions show that he paid special attention to the conditions which apply in the natural sphere, these major [metaphysical] doctrines do not presuppose his detailed investigations in natural science, but provide, rather, the framework within which they were carried out? (Aristotle: The Growth and Structure of his Thought [Cambridge: Cambridge University Press, 1968], p. 91); see also W. D. Ross's Comments in his Introduction to the Scribner's edition of Selections from Aristotle's work (New York, 1927), pp. ix?x. Most dating procedures implicitly employ a question-begging evaluative premise about what is ?most important,? or ?most mature,? or ?most Aristotelian? in the corpus.

I have followed the Oxford English translations of the Greek texts with these exceptions: for De Partibus Animalium I, I have used the Balme translation (Aristotle's De Partibus Animalium I and De Generatione Animalium I) [Oxford: Clarendon Press, 1972]; for De Generatione Animalium and Historia Animalium, A. L. Peck's translations for the Loeb Classical Library (Cambridge, University Press, 1963, 1965). Where I believe the translations are questionable, I have included the Greek, or placed angled brackets around the English expressions not mirrored in the Greek. In the notes I have used the following abbreviated forms for Aristotle's works: Cat. (Categories), De An. (De Anima), De Incessu (De Incessu Animalium), DPA (De Partibus Animalium), DGA (De Generatione Animalium), HA (Historia Animalium), Met. (Metaphysica), Pol. (Politicus). The pagination is that of the Bekker edition of the Opera. DK refers to H. Diels and W. Kranz, Die Fragmente der Vorsokratiker, 6th ed. (Berlin 1951).

On distinguishing between the various sorts of unity, see Met. V, 6, 1016b32 ff.; Met. V, 9, 1018a7 ff.; Met. X, 1, 1052a15 ff.; DPA I, 4, 644a15-23, 644b1-16; HA I, 1, 486a15; HA I, 2, 488b31-33.

Met. X, 1, 1052a15-30. There is in addition a ranking of numerical unity based on the assumption that inherent unity is more deserving of the title than that imposed by an external agency. In this ranking natural entities are, of course, one in a superior sense to artificial productions; and unit-heaps ? one only by accident of place ? are even further down the scale of numerical identity.

Met. VII, 8, 1034a1-7.

The expressions 323-1 and 323-2 are generally interchangeable in Aristotle, though on some occasions one or the other seems to possess greater generality in Aristotle's mind. At Physics I, 4, 187a15-20, and Met. VIII, 2, 1042b32-36, the former expression seems to be the more general, while the opening lines of DPA IV, 12, suggest that the latter expression is so.

Two examples of analogues relationships mentioned by Aristotle are, lungs: air-dwellers:: gills : water-dwellers (DPA I, 5, 645b8); bone : land dwellers :: spine or cartilage : water-dwellers (DPA II, 8, 653b32 ff. and Post. An. II, 14, 980a20?23). Aristotle's concept of analogy is as close to contemporary biology's as it could be, given its nonevolutionary perspective, as the following quotation makes clear: ?when the element of an ultimate ancestral structure in common is lacking ... the structures developed for the function in question are not homologous but only analogous. Insect wings, as compared with the wings of flying vertebrates, are a good example? (G. G. Simpson, The Meaning of Evolution [New York: Bantam Books, 1971], p. 163).

I will discuss Metaphysics VIII, 2, later in this paper. Aristotle never explicitly applies what he says there to organisms (which I take it are paradigmatic Aristotelian substances), but he does imply that an ?analogous? account could be given; and makes one suggestive comment on how organs are differentiated.

I should here indicate that the Aristotelian concepts of 324-1 and 324-2 do not coincide with our notions of genus and species. Most organisms now referred to as species would not be so designated by Aristotle, and most of his greatest 324-3 (Fish, Bird, Cetacea, Testacea, Crustacea, Cephalopods, Insects, Viviparous Quadrupeds, and Oviparous Quadrapeds) appear at roughly our level of classes. I will be using ?genus? (as Aristotle tends to) to refer to such groups and ?species? to refer to distinguishable types within these groupings. While I cannot argue the point here, I do not find quite the chaos in Aristotle's biological use of 324-4 and 324-5 that Balme does; see ?324-6 and 324-7 in Aristotle's Biology,? Class. Quart., xii (1962), 81 ff. The clue to sorting this issue out is Met. V, 28 (on 324-8), where Aristotle claims that one legitimate meaning of this term is in reference to genetically related series, not in reference to the underlying subject of differentiation. (1024b6?9). The reference class of the term so used would include ?species.?

Thompson, On Growth and Form, abridged ed., 1971. This edition is an abridgment of Thompson's 1942 revision of the 1917 original, and thus contains a footnote (p. 274 n. 1) to ?Excess and Defect: Or the Little More and the Little Less,? Mind, 38 (1928), 43 ff. This does not alter the fact that the two accounts are essentially polar opposites.

Ibid., p. 274. That the relationships between qualities which differ by ?excess and defect? can be expressed quantitatively is clearly implied at De Sensu 3, 439b19?440a6, esp. 439b28?33. On his passage and its implications, see R. Sorabji, ?Aristotle, Mathematics, and Colour,? Class. Quart., 22 (1972), 293?308.

In backing up this claim one might be inclined to invoke Aristotle's various remarks about ?dualizing? creatures (e.g., seals and bats) at DPA 681b5, 697a15 ff., DGA 731b8, etc.; see Stephen Clark, Aristotle's Man: Speculations upon Aristotelian Anthropology (Oxford: Oxford University Press, 1975), pp. 31?32. These claims are invariably about species which cannot be easily classified into one ?greatest kind? or another, however. Aristotle does not normally refer to a ?variety? as being difficult to classify as a member of one species rather than another. He does countenance some hybridization (see DGA II, 7, 746a29?746b13), but (see DGA II, 4, 738b26?36) claims the result, after an indeterminate number of generations, will be an offspring like the original female in form (326?1). Thus neither of these ideas speaks directly to the issue of the relationship between species of a genus, though they are further evidence against viewing Aristotle as a rigid typologist.

E.g., Met. VII, 12, 1037b18?20, 1038a5?25, and Met. X, 9, and 10. There is at least one passage where Aristotle states quite clearly that members of different species do not differ by the more and the less, Pol. I, 5, 1259b36: ?Nor can [the ruler and the ruled] differ by the more and the less, for ruler and ruled differ in form (326-2), but the more and the less do not.? Cf. Physics IV, 9, 217b5.

Here I follow Balme's translation of DPA I, 3, 624b25.

For specific applications of this notion of differentiation by the more and the less, I recommend DPA IV, 11 and 12, and my discussion below.

DPA I, 3, 643a1: ?it is not possible for some form of being which is single and indivisible to belong to things different in form, but it will always be different?; 643a7?9: ?But if the kinds of animals are indivisible, and so are the differentiae, and no differentia is common, then the differentiae will be equal to the indivisible kinds of animals.? The stress throughout chaps.2?3 is on the unity of each species, its distinctness from all others, and on the one-to-one correspondence between complete differentiation and speciation.

A. E. Taylor, ?Forms and Numbers: A Study in Platonic Metaphysics,? Mind, 35 (1927), 419?440, and 36 (1927), 12?33.

Met. XIII, 7, 1081a15. Thompson argues that 327-1 had a technical sense in Greek mathematics which it carries in this passage, referring to irrationals (p. 43). I can find no such meaning mentioned in Heath's Greek Mathematics (New York: Dover Books, 1963), and Thompson cites no texts to support this claim. At any rate, this is not at issue for the purposes of my discussion.

Thompson, ?Excess and Defect,? p. 55.

This has not prevented translators such as A. L. Peck from referring to Thompson's paper as a standard discussion of the subject (Aristotle, Parts of Animals [Cambridge, Mass.: Harvard University Press, 1968], Introduction, p. 20. n. b).

Met. V, 16, 1021b15ff.; Met. VIII, 4, 1044a33-1044b2; Met. IX, 8, 1050a15?19; De An. II, 1, 412a20 ff.

Met. VII, 12, 1038a5, and Met. VII, 13, 1038b10 ff.

See De Incessu 704b15?18; DPA IV, 12, 694a15; and further see Name Hermann Bonitz, Index Aristotelicus, vol. 15 of Aristotelius Opera (Berlin: De Gruyter et Socias, 1961), 836b28?46.

Empedocles' ?painter? fragment (DK 31B, frag. 23) notes that the pigments are harmoniously mixed 329-1, but the cosmological significance of this passage is unclear. DGA II, 6, 743b20?25, may be a conscious echo of this fragment. Cf. Anaxagoras, DK 59, B6, for a use of ?the great and small? as differentiae.

Physics I, 4, 187a15?20; Physics I, 6, 189b8?10.

Cat. 3b33 ff. But see note 31 below.

The claim that is made here goes entirely unjustified: and on the basis of DGA IV, 3, one might want to raise the issue of the status of ?monstrous creations?, which seem to be treated as less fully human than perfect developments.

The modern, evolutionary, answer is also no. What makes it possible for the eventual isolation of a new species to occur is a certain degree of constant variation (and variability) within the populations of ancestor species. See Dobzhansky, Genetics of the Evolutionary Process, pp. 30, 311?313.

In fact, in the Met. (VIII, 3, 1044a10 ff.), Aristotle allows that 330-1 will ?admit the more or less.?.

Cat. 10b26?28.

Cat. 11a11 ff.

Physics V, 2, 226b3?4.

De Sensu 5, 448a13?16.

Cf. Aristotle's remarks about the ambiguity of such terms as ?sharp,? ?flat,? ?clear,? or ?obscure,? due to their having application to more than one variety of perception (Topics I, 15, 106a9?36).

Physics V, 2, 226a26?29.

This distinction is made clearly in Aristotle's discussion of the concept of quality in chap. 14 of Met. V.

Aristotle has various expressions for such nonessential qualities, e.g., 332-1 (DPA I, 4, 644b14), 332-2 (Met. VIII, 2, 1042b22), 332-3 (DPA II, 1, 646a20). DGA V is entirely devoted to discussing the variations within a species of these qualities, which are taken to be allowable variations of the differentiae of a given species. It is of importance, as well shall see, that Aristotle's primary criterion for distinguishing these qualities from those essential to a species is whether or not they are for the sake of anything; they are not distinguished on morphological or taxonomic grounds.

Met. VIII, 2, 1042b30?34.

Met. VIII, 2, 1043a3?8, 1042b33.

Met. VIII, 2, 1042b21?25.

Met. VIII, 2, 1042b32?34.

Met. VIII, 2, 1042b28?31.

Cf. Met. VII, 16, 1034a5?8; DPA I, 4, 644b9.

The central texts for the theory that genus is matter are Met. V, 6, 1016a27; Met. V, 28, 1024b8; Met. VII, 12, 1038a6?7; Met. VIII, 6, 1045a35; Met. X, 3, 1054b30; Met. X, 8, 1058a23?24; and DPA I, 3, 643a24.

The concept of genus as matter has been the subject of a recent exchange between Richard Rorty (?Genus as Matter: A Reading of Metaphysics Z-H,? in Exegesis and Arguments, ed. E. N. Lee, A. P. D. Mourelatos, R. M. Rorty, Phronesis supplementary vol. 1 [Assen: Vangorcum, 1973], pp. 393?420; ?Matter as Goo: Comments on Grene's paper,? Syntheses, 28 [1874], 71?77) and Marjorie Grene (?Is Genus to Species as Matter to Form? Aristotle and Taxonomy,? Synthese, 28 [1974], 51?69). In my account I have attempted to retain the Rorty reading for natural substances (my primary concern) while widening the equation of genus and matter to include those counterexamples raised by Grene to Rorty's reading.

They are many. For a good summary see J. H. Lesher, ?Aristotle on Form, Substance, and Universals: A Dilemma,? Phronesis, 17 (1972), 169?179.

The debate goes on, of course. In recent years taxonomists and systematists have debated the ?reality? of taxa above the species level, arguing that only at the species level is there an actual organizational bond (potential interbreeding) among individuals. See Ernst Mayr, Populations, Species, and Evolution (Cambridge, Mass.: Harvard University Press, 1963), pp. 12-20; G. G. Simpson, Principles of Animal Taxonomy (New York: Columbia University Press, 1961), chap. 6; Ghiselin, The Triumph of the Darwinian Method, chap. 4, J. R. Gregg, The Language of Taxonomy (New York: Columbia University Press, 1954). A useful survey of the issues is found in the papers by Mayr, Pratt, and Hull in Topics in the Philosophy of Biology, ed. Marjorie Grene and Everett Mendelsohn, Boston Studies in the Philosophy of Science, vol. 27 (Boston: Reidel, 1976).

Cf. Met. VII, 13, 1038b10?18.

Met. V, 28, 1024b6?9. The first two meanings are the standard Greek usage from Homer on, and the phylogenetic content of this meaning is implicit in Aristotle's use of the term in his biology. This goes a long way toward explaining the apparently ?rough and ready? use of 335-1 and 335-2 (see note 11 above). The referents of meanings 1 and 2 will sometimes be species members.

Met. X, 8, 1058a23?25.

Met. VII, 12, 1038a6.

Met. VII, 12, 1038a7?8.

Met. X, 8, 1057b37-1058a5.

DPA I, 3, 643a1?5. Balme translation, but translating 336-1 in 643a2 as ?kind? rather than ?species.?

DGA II, 6, 743b20?25.

DGA II, 3, 736b2?5.

DGA IV, 3, 768b13?15.

See Bonitz, Index Aristotelicus, 26a25?61.

DPA I, 3, 642b25?29.

DPA I, 3, 644a6?10.

DPA I, 3, 643b10?13.

DPA I, 3, 643a23?24.

On the notion of phylogenesis as tending to progress from more generalized to more specialized forms, see the discussions in Simpson, Principles of Animal Taxonomy, pp. 93?101; Bernhard Rensch, Evolution above the Species Level (New York: Columbia University Press, 1959), chap. 6; W. E. LeGros Clark, The Fossil Evidence for Human Evolution (Chicago: University of Chicago Press, 1964), pp. 41?47; and cf. Darwin's guarded discussion in On the Origin of Species (pp. 120?132 of the Collier edition).

DPA I, 3, 643a24?27.

Balme, 643a24n, p. 114.

DPA IV, 12, 694b15?20.

Met. VIII, 3, 1044a10?12.

DPA I, 1, 639b15, 20, 641a2, 641a28, 641b11?12.

71.DPA IV, 12, 692b3?5.

De Incessu 704b15?18, and note 25, above.

DPA IV, 12, 694b6?8.

DGA II, 1, 734b21?735a4; De An. II, 4, 416a17.

De An. II, 1, 412a28?413a10.

De An. II, 2, 413a30; and this approach is echoed in the opening chapter of DPA. ?If, then, the form of living things is soul or some aspect of soul ... then the natural scientist ought to speak of and understand the soul? (641a18?22).

DGA V, 1, 779b26?27.

DGA V, 1, 779b33?34.

Much of what I say here is, I believe, supported by David Balme's unpublished paper ?Forms and Species in Aristotle's Biology,? read at the 1976 Princeton Colloquium on Aristotle's biology. I have benefited a great deal from Balme's comments on an earlier draft of this paper.

On Growth and Form, p. 9. On Thompson's attitude toward natural selection as the cause of adaptation, see the comments of J. T. Bonner in his introduction, p. x.