Abstract
The species problem is often described as the abundance of conflicting definitions of species, such as the biological species concept and phylogenetic species concepts. But biologists understand the notion of species in a non-definitional as well as a definitional way. In this article I argue that when they understand species without a definition in their mind, their understanding is often mediated by the notion of good species, or prototypical species, as the idea of “prototype” is explicated in cognitive psychology. This distinction helps us make sense of several puzzling phenomena regarding biologists’ dealing with species, such as the fact that in everyday research biologists often behave as if the species problem is solved, while they should be fully aware that it is not. I also briefly discuss implications of this finding, including that some extant attempts to answer what the nature of species is have an inadequate assumption about how the notion of species is represented in biologists’ minds.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
Names of concepts are written in italics.
See Footnote 10 on whether the objections affect the arguments in the present article.
Note that “good species” is an unofficial term and thus its usages may greatly vary from one biologist to another. Thus I do not claim that this is the only usage of the term. What I will do below is to suggest that biologists do use “good species” in a certain way, but this doesn’t preclude the possibility that biologists use the term in other ways. See Footnote 6 for such a usage.
I thank an anonymous referee for bringing my attention to this point.
I am inclined to offer an interesting instance of this usage of “good species.” Cronquist (1978), a plant taxonomist, quotes, as “an old joke” among taxonomists, “a good species is what a good taxonomist says it is” and compares this with a statement on pornography made by Potter Stewart, a judge of the Supreme Court of the Unites States, that “hard-core pornography” was hard to define, but “I know it when I see it.” The same comparison is made by Pigliucci and Kaplan (2006) (without mentioning Cronquist), although they simply use the term “species,” not “good species.” Here Cronquist and Stewart both appeal to collective coincidence of judgments on membership of the categories—if Judge Stewart had not believed that other people would agree with his judgment, one might ask why he made such an argument because the appeal to his intuitive judgment would not be persuasive at all.
It is important to remember that I do not intend to say that this is the only way in which biologists use the phrase, and that some of the other usages in fact do not fit with the one discussed here. For example, biologists often do use “good species” to refer to a taxon if it satisfies a single species criterion rather technically (see Dumont 2004 for one instance). It should come as no surprise given that “good species” has no official definition.
The point is, however, that biologists often do use the phrase in the way I have suggested, and this usage can be subject to analysis in terms of psychological theories of concepts, as I will do in the next section.
One might object that Mayr may in fact see incipient species as non-species and thus think that there are no borderline cases. But this is not the case. See Mayr 1942, p. 114.
The use of prototypes in taxonomic practice may be more widespread than this section suggests. Hey (2001, p. 162) points out that when taxonomists engage in species classification, they often rely on a prototype of that species and treat each species as if it is a natural kind, rather than an individual.
As I noted in this section, the prototype of species, good species, is characterized by the consilience of different properties. This makes our proposal look like one of the cluster views of species, including the homeostatic property cluster theory (Boyd 1999) and David Hull’s cluster definition of species (Hull 1965). The difference, however, lies in the fact that our proposal is not about the species category per se, but about its prototype. It can be the case that a category has a prototypical member while it has sharp boundaries: even number is a sharply delineated category but does have a prototypical member, such as 2. Likewise our proposal does not preclude the possibility that the species category is not characterized by a cluster of properties.
In this section I applied the prototype theory of concept to analyse biologists’ attitudes toward the concept of species. One might suspect that this was only possible if I downplay or ignore the fact that there are several objections to the prototype theory in cognitive psychology (see, for example, Laurence and Margolis 1999, for the objections). Yet this does not mean that the use of the prototype theory in the present paper is not warranted. For our purposes, it is not necessary to assume that the prototype theory is the appropriate account of concept. Our proposal is compatible with pluralism about the concept of concept. It is because our aim is to point to some unattended aspects in biologists’ use of the concept “species” and to explore their philosophical implications. In this context, we need an assumption that the prototype theory accounts for the phenomena in question, but not an assumption that it accounts for all the phenomena about concept.
And pluralism about concept is a sensible position. We cannot go into the details of the debate, but several authors are sympathetic to the pluralistic account of concept (see for example Machery 2008).
It should be noted that one might take the persistence question more narrowly. According to the present description, the resolution of the species problem is not restricted to agreeing on the nature of species. If, for example, the biological community comes to agree that the species category is not a natural kind and abandons the project of giving a definition of it altogether, this would also be taken as a “resolution” of the problem in this description, because the species problem would no longer appear as a “problem” to biologists. In other words, in our interpretation, one aspect of the persistence of the species problem is that biologists feel pressed to solve the problem in one way or another.
Recently Ereshefsky (2010) changed his position and now admits that the term “species” is so entrenched in biologists’ practice that it is not practical to eliminate it. But he gives little analysis to the psychological and epistemological roles species plays in biologists’ minds.
They do conduct experiments, but subjects are typically non-scientists (in Klahr’s experiments) and the experimental task is not about what scientists actually work on in their research (in Nersessian’s case).
References
Armstrong S, Gleitman L, Gleitman H (1983) What some concepts might not be. Cognition 13:263–308
Boyd R (1999) Homeostasis, species, and higher taxa. In: Wilson R (ed) Species: new interdisciplinary essays. MIT Press, Cambridge, pp 141–185
Brigandt I (2003) Species pluralism does not imply species eliminativism. Philos Sci 70:1305–1316
Chan K, Levin S (2005) Leaky prezygotic isolation and porous genomes: rapid introgression of maternally inherited DNA. Evolution 59:720–729
Coyne J, Orr H (2004) Speciation. Sinauer, Sunderland
Cronquist A (1978) Once again, what is a species? Biosystematics in agriculture. Rombergered Allanheld & Osmun, Montclair, pp 3–20
Darwin C (1859) On the origin of species by means of natural selection. John Murray, London
Dumont H (2004) Distinguishing between the East-Asiatic representatives of paracercion weekers and dumont (Zygoptera: Coenagrionidae). Odonatologica 33:361–370
Ereshefsky M (1992) Eliminative pluralism. Philos Sci 59:671–690
Ereshefsky M (2010) Darwin’s solution to the species problem. Synthese 175:405–425
Franks J, Bransford J (1971) Abstraction of visual patterns. J Exp Psychol 90:65–74
Hamada N, Adler P (1999) Cytotaxonomy of four species in the Simulium perflavum species group (Diptera: Simuliidae) from Brazilian Amazonia. Syst Entomol 24:273–288
Hey J (2001) Genes, categories, and species. Oxford University Press, Oxford
Holland J, Holyoak K, Nisbett R (1989) Induction: processes of inference, learning, and discovery. MIT Press, Cambridge
Hull D (1965) The effect of essentialism on taxonomy—two thousand years of stasis II. Br J Philos Sci 16:1–18
Kahneman D, Frederick S (2002) Representativeness revisited: attribute substitution in intuitive judgment. In: Gilovich T, Griffin D, Kahneman D (eds) Heuristics and biases. Cambridge University Press, Cambridge, pp 49–81
Klahr D (2000) Exploring science: the cognition and development of discovery processes. MIT Press, Cambridge
Lakoff G (1973) Hedges: a study in meaning criteria and the logic of fuzzy concepts. J Philos Log 2:458–508
Lakoff G (1989) Cognitive models and prototype theory. In: Neisse U (ed) Concepts and conceptual development. Cambridge University Press, Cambridge, pp 63–100
Laurence S, Margolis E (1999) Concepts and cognitive science. In: Margolis E, Laurence S (eds) Concepts: core readings. MIT Press, Cambridge, pp 3–81
Luckow M (1995) Species concepts: assumptions, methods, and applications. Syst Bot 20:589–605
Machery E (2008) Doing without concepts. Oxford University Press, Oxford
Machery E (2012) Why I stopped worrying about the definition of life\(\ldots\) and why you should as well. Synthese 185:145–164
Mallet J (1995a) Reply from mallet. Trends Ecol Evol 10:490–491
Mallet J (1995b) A species definition for the modern synthesis. Trends Ecol Evol 10:294–299
Mallet J (1996) Reply from Mallet. Trends Ecol Evol 11:174–174
Mayr E (1942) Systematics and the origin of species from the viewpoint of a zoologist. Columbia University Press, New York
Murphy G (2002) The big book of concepts. MIT Press, Cambridge
Nersessian N (2008) Creating scientific concepts. MIT Press, Cambridge
Pigliucci M, Kaplan J (2006) Making sense of evolution. University of Chicago Press, Chicago
Predelli S (2003) Scare quotes and their relation to other semantic issues. Linguistics and philosophy 26:1–28
Reydon T (2005) On the nature of the species problem and the four meanings of ‘species.’ Stud Hist Philos Biol Biomed Sci 36:135–158
Rosch E (1975) Cognitive representations of semantic categories. J Exp Psychol 104:192–233
Rosch E (1978) Principles of categorization. In: Rosch E, Lloyd B (eds) Cognition and categorization. Erlbaum, Hillsdale, pp 27–48
Rosch E, Mervis C (1975) Family resemblances: studies in the internal structure of categories. Cogn Psychol 7:573–605
Smith E, Osherson D, Rips L, Keane M (1988) Combining prototypes: a selective modification model. Cogn Sci 12:485–527
Templeton A (1989) The meaning of species and speciation: a genetic perspective. In: Otte D, Endler J (eds) Speciation and its consequences. Sinauer, Sunderland
Wilkins J (2009a) Species: a history of the idea. University of California Press, Berkeley
Wilkins J (2009b) Species are not theoretical objects, or, on what there is in biology. http://philsci-archive.pitt.edu/archive/00004835/. Accessed 19 July 2009
Winston J (1999) Describing species: practical taxonomic procedure for biologists. Columbia University Press, New York
Acknowledgments
Versions of this paper were presented at several places including the University of Pittsburgh, the Kazimierz Naturalist Workshop (Kazimierz Dolny, Poland), the Annual Symposium of the Union of the Japanese Societies for Systematic Biology (National Museum of Nature and Science, Japan), the Japan-Korea Workshop on Philosophy of Science (Kyoto University, Japan), the Japan-Taiwan Philosophy of Biology Workshop (National Chung Cheng University, Taiwan), and the biannual meeting of the International Society for the History, Philosophy and Social Studies of Biology (Brisbane, Australia). I thank the participants for helpful comments. I am very grateful to the following people for improvements to this paper which I could not have made without them: John Beatty, Marc Ereshefsky, Chris Stephens, the late Brian Laetz, the research fellows of the Center for Philosophy of Science at the University of Pittsburgh, and two anonymous reviewers of this journal. This work is financially supported by JSPS KAKENHI (Grant Number: 25370016).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Amitani, Y. Prototypical Reasoning About Species and the Species Problem. Biol Theory 10, 289–300 (2015). https://doi.org/10.1007/s13752-015-0204-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13752-015-0204-4