Published online by Cambridge University Press: 14 March 2022
Prior to the advent of evolutionary theory the Natural System was generally conceived as based on “distinctions of kind, not consisting in a given number of definite properties” (J.S. Mill). It was considered final and unique, to be arrived at by more than one approach. Evolutionary theory has shifted emphasis to different characters, yet explicitly or implicitly the belief in a final natural system in biology persists in many textbooks and taints research. Allegedly natural systems are shown to be fundamentally arbitrary and artificial, dependent on numerous value judgments and intrinsically conflicting to varying degrees. Because of this and because it has turned into a bar to clear thinking, the adjective “natural” should be abolished.
1 Guyenot, E. Les sciences de la vie aux XVII et XVIII siècles. L'idée d'évolution. Paris, 1941, p. 29-35.
2 Incidentally, Adanson is said to have first used “family” to denote a natural group of plants (Nordenskiöld, E. The History of Biology, transi. L. B. Eyre, London 1929, p. 436).
3 “Adanson's claims of priority over Bernard de Jussieu may be passed over as unimportant” (Sachs, J. von. History of Botany (1530-1860). Transi. H. Garnsey. Oxford 1906, p. 116).
4 Raven, C. E. John Ray, Naturalist. Cambridge 1950, p. 187-191.
5 Linnaeus, C. Philosophia botanica, Stockholmiae 1751, p. 31. “Methodus” as used here should properly be translated “System”. Earlier, Ray and others had used it in the same sense.
6 Linnaeus, C. Classes plantarum, Leyden, 1738, p. 484.
7 Linnaeus, C. Genera plantarum, Holmiae, 1764, p. 177.
8 Linnaeus, C. Classes plantarum, l.c., p. 487.
9 Linnaeus, C. Philosophia botanica, l.c., p. 31.
10 “Omnia genera naturalia sunt”. Genera plantarum.
11 “Plantae quae genera conveniunt etiam virtute conveniunt, quae ordine naturali continentur etiam virtute proprius accedunt, quaeque classe naturali congruunt etiam viribum quodam modo congruunt”. Philosophia botanica, l.c, p. 282.
12 Cuvier, G. La règne animal, Paris, 1817.
13 Published in Paris, 1819; the first edition published 1813.
14 Théorie élémentaire, p. 73.
15 Théorie élémentaire, p. 23.
16 l.c., p. 35.
17 l.c., p. 37-8.
18 l.c., p. 52-3.
19 l.c., p. 76.
20 l.c., p. 79.
21 l.c., p. 56.
22 l.c., p. 83.
23 Schleiden, M. J. Handbuch der medizinisch-pharmaceutischen Botanik, Leipzig, 1852 (p. 116).
24 Cassirer, E. The Problem of Knowledge. Transi. Woglom and Hendel. New Haven 1950, p. 124-125. See also the very interesting study by Roretz, K. (Zur Analyse von Kants Philosophie des Organischen. Wien 1922), p. 128-137, ‘Kants Rassentheorie’. Kant explicitly distinguishes “Naturgattung” (“Realgattung”) and “Schulgattng” (“Nominalgattung”), corresponding to what he terms “Natureinteilung” and “Schuleinteilung”.
24a Such pre-established harmony was not always accepted. Thus in 1700 Fontenelle, discussing Tournefort's views, wrote “. . . cet ordre si nécessaire n'a point été établi par la Nature, qui a préféré une confusion magnifique à la commodité des physiciens. Et c'est à eux à mettre presque malgré elle de l'arrangement et un système dans les plantes”. (Quoted by Leroy in “ Tournefort,” Paris 1957, p. 202. Leroy considers this an unfair representation of Tournefort's views). Also Goethe: “Natürlich System, ein widersprechender Ausdruck” — Problem und Erwiederung, Saemmtliche Werke, Stuttgart 1875 (Cotta), vol. 9, p. 685-691.
25 The later editions of the System of Logic were published after The Origin of Species, yet Mill's approach to the problems of Natural System was not influenced by this. (See also M. St. Packe, The Life of John Stuart Mill, London, 1954).
26 This belief in the pre-established system of plants provides a possible explanation for the peculiar grammatical treatment of generic descriptions in “Die natürlichen Pflanzenfamilien”. For these descriptions are consistently given in either the singular or the plural, according to whether the genus concerned is recognized as including one or more species. This implies, as it were, the existence of two kinds of genera—genera with one and genera with more than one species. (Inconsistencies in this treatment in the second edition could be shown to be due to faulty adaptation of the first-edition text to the increase in number of species).
27 Hartmann, M. Gesammelte Vortraege II, Jena 1956, p. 57.
28 Remane, A. Die Grundlagen des Natürlichen Systems, der vergleichenden Anatomie und der Phylogenetik, 2nd ed., Leipzig, 1956, p. 97.
29 Joshi, A. C. Some salient points in the evolution of the secondary vascular cylinder of Amaranthaceae and Chenopodiaceae. Am. J. Bot. 26, 3-9, 1937.
30 Others may take the opposite view, i.e., “Problem taxa such as Krameria make present-day taxonomy the exciting field it is. One never knows how new evidence will affect the taxonomic scales”. (Turner, B. L. Chromosome numbers in the genus Krameria: Evidence for familial status. Rhodora 60, 101-106, 1958).
31 Gemeroy, D.C. in Abstracts of papers presented to the 15th International Congress of Zoology, section ii paper 4, London, 1958.
32 Even though some authors measure both the amount of precipitate and the degree of turbidity, as far as evaluation of relationships is concerned, the same criticism holds.
33 Leone, C. A. Further serological data on the relationships of some decapod Crustacea. Evolution, 8, 192-205, 1954.
34 e.g., Merker, E. Chromatographische Artbestimmung von Tannenlausen der Gattung Dreyfusia. Die Naturwiss. 45, 118-9, 1958. Also next item, and many others.
35 Roberts, E. A. H., Wight, D. and Wood, D. J. Paper chromatography as an aid to the taxonomy of Thea Camellias. New Phytol. 57, 211-226, 1958 (my italics).
36 Dittrich, M. Zum Problem der Tierwerdung der Pflanze. Wiss. Z. d. Martin Luther Universität, Halle-Wittenberg, 4, 429-470, 1955.
37 Hutchinson, J. Contribution towards a phylogenetic classification of flowering plants iii. Kew Bull., 49-66, 1924.
38 Gams, H. Die Protochlorinae als autotrophe Vorfahren von Pilzen und Tieren ? Mikroskopie 11, 383-387, 1948. See also: Moreau, M, Les champignons sont-ils des vegetaux ou des animaux. Bull. Res. Counc. Israel, 10 D, 1961.
39 Rollins, R. The genetic evaluation of a taxonomic character in Dithyrea (Cruciferae). Rhodora 60, 145-152, 1958.
40 This passage is strikingly reminiscent of Rivinus' discussion of the status of the genus Onobrychis: “And why indeed are Glycirrhiza medica and G. scorpioides, with a spiny fruit, not referred to Onobrychis if in the same genus are to be united leguminous plants with spiny or hispid plants?” Rivinus, A. Q. Ordo Plantarum —Flore Irregulari Tetrapetala. Lipsieae. 1691.
41 Sporne, K. R. Statistics and the evolution of dicotyledons. Evolution 8, 55-64, 1954. See also Michener, C. D. and R. S. Sokal: A quantitative approach to a problem in classification. Evolution 11, 13-162, 1957.
42 Cain, A. J. The post-Linnean development of taxonomy. Proc. Linn. Soc. London 170, 234-244, 1959. Earlier, Cain has discussed ways to compute the M.C.D. (Mean Character Difference) of species (Cain, A. J. and G. A. Harrison. An analysis of the taxonomist's judgment of affinity. Proc. Zool. Soc. London, 131, 85-98, 1958). Since then, programs have been prepared for the IBM 650 digital computer to carry out an analysis resembling the weighted variable group method in a few minutes (Sokal, R. R. Comments on quantitative systematics. Evolution 13, 420-430, 1959).
43 International code of botanical nomenclature, adopted by the 8th International Botanical Congress, Utrecht, 1956. Incidentally, this has led to a peculiar situation, in that the time spent on the discovery of the proper name for classes of plants may exceed the time spent on the study of the plants themselves.
44 The pleiotropic action of a single gene may be such that the same gene responsible for a certain resistance pattern to one or several insecticides may at the same time be responsible for susceptibility to some other compound. “In Drosophila ... greater susceptibility to phenylthiocarbamide derives from the gene allele at 11-67 which is responsible for resistance to DDT and other insecticides”. (Brown, A. W. A., in Abstracts of Papers presented to the XV International Congress of Zoology, Sect. VI, Paper 62, London 1958).
45 Not always, though, as the young stages may show characters which are completely obliterated upon further development.
46 Celarier, R. R. and K. L. Mehra. Determination of polyploidy from herbarium specimens. Rhodora 60, 89-97, 1958.