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Explanatory unification and natural selection explanations

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Abstract

The debate between the dynamical and the statistical interpretations of natural selection is centred on the question of whether all explanations that employ the concepts of natural selection and drift are reducible to causal explanations. The proponents of the statistical interpretation answer negatively, but insist on the fact that selection/drift arguments are explanatory. However, they remain unclear on where the explanatory power comes from. The proponents of the dynamical interpretation answer positively and try to reduce selection/drift arguments to some of the most prominent accounts of causal explanation. In turn, they face the criticism raised by statisticalists that current accounts of causation have to be violated in some of their core conditions or otherwise used in a very loose manner in order to account for selection/drift explanations. We propose a reconciliation of both interpretations by conveying evolutionary explanations within the unificationist model of scientific explanation. Therefore, we argue that the explanatory power in natural selection arguments is a result of successful unification of individual- and population-level facts. A short case study based on research on sympatric speciation will be presented as an example of how population- and individual-level facts are unified to explain the morphological mosaic of bill shape in island scrub jays (Aphelocoma insularis).

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Notes

  1. Fitness usually refers to reproductive success, but there are cases in which persistence is more appropriate, such as when we are dealing with super-organisms, colonial organisms, etc. For a full account, see Bouchard (2008).

  2. Part of the purpose of Lenski’s long-term experiment was to test for the role of historical contingency for evolutionary outcomes. His 12 initially identical lineages of Escherichia coli could be interpreted as parallel worlds with a starting hamming distance that is as small as possible. In generation 31,500 lineage, Ara-3 displayed the ability to exploit citrate as a resource. Since all populations are exposed to the same environment, Ara-3 obviously has a selective advantage over the other 11 lineages. However, the ability to exploit citrate as a resource is due to a specific sequence of mutations (Blount et al. 2012), which makes it a fragile event. Therefore, if we use possible world logic, as proposed by Huneman, we should classify the adaptive success of Ara-3 as a drift outcome.

  3. For instance, in some species female preferences and male success fluctuate and interact with other environmental pressures in a non-trivial way, creating a mosaic of traits instead of the expected cline (Gosden and Svensson 2008). This presents no clear-cut way to sort out the nexus of causal interactions that lead to the diversification. Instead of trying to analyse the data in terms of grading causal relevant factors, the situation is more easily modelled via a dynamic adaptive landscape model that captures broadly the selective pressures and the population’s dynamic (Svensson and Calsbeek 2013).

  4. This is actually a general objection in applying the process account of causality to explanations. Process accounts of causality usually correctly give a necessary condition for two events to be causally related, however they do not necessarily pick up the most relevant difference-makers, which should figure in the explanation. To quote Woodward: ‘we still face the problem that the feature that makes a process causal (transmission of some conserved quantity or other) tells us nothing about which features of the process are causally or explanatorily relevant to the outcome we want to explain’ (Woodward 2003, p. 357).

  5. STP: An action C that increases the probability of event E in each sub-population increases the probability of E in the population as a whole, provided that the action does not change the distribution of the sub-populations (Pearl 2000, p. 181).

  6. Note that evolutionary explanations require a connection between at least two explanatory levels: The first is the deterministic level of individual interactions, and the second is the macro-level of evolutionary outcomes, which depends on statistical representations of populations. Even though the two levels are clearly inter-related, no universally accepted way of exhaustive epistemic reduction of the macro-level to the micro-level exists. The situation is perhaps analogical to what Michael Berry described as: ‘Even within physical science, reduction between different levels of explanation is problematic—indeed, it is almost always so’ (Berry 2001, p. 43).

References

  • Baker A (2005) Are there genuine mathematical explanations of physical phenomena? Mind 114:223–238

    Article  Google Scholar 

  • Bartelborth T (2002) Explanatory unification. Synthese 130:91–108

    Article  Google Scholar 

  • Berry MV (2001) Chaos and the semiclassical limit of quantum mechanics (Is the moon there when somebody looks?). In: Russell RJ, Clayton P, Wegter-McNelly K, Polkinghorne J (eds) Quantum mechanics: scientific perspectives on divine action, vol 5. Vatican Observatory CTNS Publications, Vatican City, pp 41–54

    Google Scholar 

  • Blount ZD, Borland CZ, Lenski RE (2008) Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli. Proc Natl Acad Sci USA 105:7899–7906

    Article  Google Scholar 

  • Blount ZD, Barrick JE, Davidson CJ, Lenski RE (2012) Genomic analysis of a key innovation in an experimental Escherichia coli population. Nature 489:513–518

    Article  Google Scholar 

  • Bolnick DI, Fitzpatrick BM (2007) Sympatric speciation: models and empirical evidence. Annu Rev Ecol Evol Syst 38:459–487

    Article  Google Scholar 

  • Bouchard F (2008) Causal processes, fitness and the differential persistence of lineages. Philos Sci 75:560–570

    Article  Google Scholar 

  • Bouchard F, Rosenberg A (2004) Fitness, probability and the principles of natural selection. Br J Philos Sci 55:693–712

    Article  Google Scholar 

  • Brigandt I (2013) Explanation in biology: reduction, pluralism, and explanatory aims. Sci Educ 22:69–91

    Article  Google Scholar 

  • Dowe P (2000) Physical causation. Cambridge University Press, New York

    Book  Google Scholar 

  • Friedman M (1974) Explanation and scientific understanding. J Philos 71:5–19

    Article  Google Scholar 

  • Garfinkel A (1991) Reductionism. In: Boyd R, Gasper P, Trout JD (eds) The philosophy of science. The MIT Press, Cambridge, pp 443–461

    Google Scholar 

  • Gillespie JH (1974) Natural selection for within-generation variance in offspring number. Genetics 76:601–606

    Google Scholar 

  • Gosden TP, Svensson EI (2008) Spatial and temporal dynamics in a sexual selection mosaic. Evolution 62:845–856

    Article  Google Scholar 

  • Gould SJ (1989) Wonderful life: the Burgess Shale and the nature of history. Norton, New York

    Google Scholar 

  • Huneman P (2012) Natural selection: a case for the counterfactual approach. Erkenntnis 76:171–194

    Article  Google Scholar 

  • Kaplan JM (2013) “Relevant similarity” and the causes of biological evolution: selection, fitness, and statistically abstractive explanations. Biol Philos 28:405–421

    Article  Google Scholar 

  • Kitcher P (1989) Explanatory unification and the causal structure of the world. In: Kitcher P, Salmon WC (eds) Scientific explanation. University of Minnesota Press, Minneapolis, pp 410–505

    Google Scholar 

  • Lange M (2013) What makes a scientific explanation distinctively mathematical? Br J Philos Sci 64:485–511

    Article  Google Scholar 

  • Langin KM, Sillett TS, Funk WC, Morrison SA, Desrosiers MA, Ghalambor CK (2015) Islands within an island: repeated adaptive divergence in a single population. Evolution 69:653–665

    Article  Google Scholar 

  • Lewis D (1986) Philosophical papers, vol II. Oxford University Press, Oxford

    Google Scholar 

  • Love AC (2008) Explaining evolutionary innovation and novelty: criteria of adequacy and multidisciplinary prerequisites. Philos Sci 75:874–886

    Article  Google Scholar 

  • Lyon A, Colyvan M (2008) The explanatory power of phase spaces. Philos Math 16:227–243

    Article  Google Scholar 

  • Masel J (2011) Genetic drift. Curr Biol 21:R837–R838

    Article  Google Scholar 

  • Matthen M (2009) Drift and “statistically abstractive explanation”. Philos Sci 76:464–487

    Article  Google Scholar 

  • Matthen M, Ariew A (2009) Selection and causation. Philos Sci 76:201–224

    Article  Google Scholar 

  • Maynard Smith J (1966) Sympatric speciation. Am Nat 100:637–650

    Article  Google Scholar 

  • Millstein RL (2002) Are random drift and natural selection conceptually distinct? Biol Philos 17:33–53

    Article  Google Scholar 

  • Millstein RL (2006) Natural selection as a population-level causal process. Br J Philos Sci 57:627–653

    Article  Google Scholar 

  • Millstein RL (2008) Distinguishing drift and selection empirically: “the great snail debate” of the 1950s. J Hist Bio 41:339–367

    Article  Google Scholar 

  • Millstein RL (2009) Concepts of drift and selection in ‘the great snail debate’ of the 1950s and early 1960s. In: Cain J, Ruse M (eds) Descended from Darwin: insights into the history of evolutionary studies, 1900–1970. American Philosophical Society, Philadelphia, pp 271–298

    Google Scholar 

  • Millstein RL, Skipper RA Jr, Dietrich MR (2009) (Mis)interpreting mathematical models: drift as a physical process. Philos Theory Biol. doi:10.3998/ptb.6959004.0001.002

    Google Scholar 

  • Pearl J (2000) Causality: models, reasoning, and inference. Cambridge University Press, Cambridge

    Google Scholar 

  • Petkov S (2015) Explanatory unification and conceptualization. Synthese. doi:10.1007/s11229-015-0716-2

    Google Scholar 

  • Salmon WC (1984) Scientific explanation and the causal structure of the world. Princeton University Press, Princeton

    Google Scholar 

  • Salmon WC (1989) Four decades of scientific explanation. University of Minnesota Press, Minneapolis

    Google Scholar 

  • Schurz G (1999) Explanation as unification. Synthese 120:95–114

    Article  Google Scholar 

  • Sober E (2001) The two faces of fitness. In: Singh RS, Krimbas CB, Paul DB, Beatty J (eds) Thinking about evolution: historical, philosophical, and political perspectives. Cambridge University Press, Cambridge, pp 309–321

    Google Scholar 

  • Sober E (2013) Trait fitness is not a propensity, but fitness variation is. Stud Hist Philos Sci C Stud Hist Philos Biol Biomed Sci 44:336–341

    Article  Google Scholar 

  • Strevens M (2004) The causal and unification approaches to explanation unified—causally. Noûs 38:154–176

    Article  Google Scholar 

  • Svensson EI, Calsbeek R (2013) The adaptive landscape in evolutionary biology. Oxford University Press, Oxford

    Book  Google Scholar 

  • Walsh DM (2004) Bookkeeping or metaphysics? The units of selection debate. Synthese 138:337–361

    Article  Google Scholar 

  • Walsh DM (2007) The pomp of superfluous causes: the interpretation of evolutionary theory. Philos Sci 74:281–303

    Article  Google Scholar 

  • Walsh DM (2013) Descriptions and models: some responses to Abrams. Stud Hist Philos Sci C Stud Hist Philos Biol Biomed Sci 44:302–308

    Article  Google Scholar 

  • Walsh DM (2014) Variance, invariance and statistical explanation. Erkenntnis. doi:10.1007/s10670-014-9680-3

    Google Scholar 

  • Weber E, Van Dyck M (2002) Unification and explanation: a comment on Halonen and Hintikka, and Schurz. Synthese 131:145–154

    Article  Google Scholar 

  • Woodward J (2003) Making things happen: a theory of causal explanation. Oxford University Press, Oxford

    Google Scholar 

  • Woodward J (2010) Causation in biology: stability, specificity, and the choice of levels of explanation. Biol Philos 25:287–318

    Article  Google Scholar 

Download references

Acknowledgements

This paper is supported by National Foundation of Social Science of China; Program name: Studies on the Key Problems of Philosophy of Biology; Program number: 14ZDB171.

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Authors and Affiliations

  1. Institute of Science, Technology and Society, Tsinghua University, Room 247, Building Mingzhai, Beijing, 100084, China

    Stefan Petkov

  2. Institute of Science, Technology and Society, Tsinghua University, Room 259, Building Mingzhai, Beijing, 100084, China

    Wei Wang

  3. Institute of Science, Technology and Society, Tsinghua University, Room 242, Building Mingzhai, Beijing, 100084, China

    Yi Lei

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  1. Stefan Petkov
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Correspondence to Stefan Petkov.

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Petkov, S., Wang, W. & Lei, Y. Explanatory unification and natural selection explanations. Biol Philos 31, 705–725 (2016). https://doi.org/10.1007/s10539-016-9523-5

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