In this paper I assess the explanatory role of idealizations in ‘design explanations’, a type of functional explanation used in biology. In design explanations, idealized, non-existent organisms (organisms with non-existent characteristics) are invoked to make salient which traits of extant organisms make a difference to organismal fitness, understood in terms of higher life chances. For instance, by comparing gulls with white underparts with hypothetical, idealized ones with black underparts, the trait of ‘having white underparts’ is shown to be advantageous; it offers increasing hunting success (Götmark 1987). Similarly, the giant eyes of giant deep see squid are shown to make a difference to fitness by comparing giant squid with giant eyes with hypothetical, idealized ones having smaller eyes; large eyes enable the detection of predators (sperm whales) which would not be possible or less efficient if the squid were to have smaller eyes (cf. Nilsson et al. 2012). Such advantages offered by traits are explained in terms of ‘functional dependence relations’, which relate advantages offered by a trait to contextual conditions (Wouters 2007, p. 76). In the case of gulls with white underparts, for example, the advantages offered by this trait are importantly related to external conditions, such as the brightness of the sky, and internal conditions like ‘not being nocturnal’. If gulls were to hunt at night, any advantage – hunting success - offered by their white underparts probably vanishes.
Given the reliance on comparisons with idealized, non-existent organisms, I argue that in design explanations, idealizations highlight which factors – traits of extant organisms – make a difference to organismal fitness.
I take ‘idealization’ to refer to the intentional distortion or misrepresentation of facts, i.e., the assertion of falsehoods, thus distinguishing it from ‘abstraction’, understood as the omission of veridical details, without misrepresentation (cf. Jones 2005).
This result negates the view that idealizations serve only pragmatic benefits (cf. McMullin 1985), complements the view that idealizations function to highlight factors that do not make a difference (cf. Strevens 2007, 2008), and in particular strengthens the perspective that idealizations are means to highlight difference making factors (cf. Weisberg 2007; Batterman 2009; Rice 2013). In some explanatory contexts, idealizations are in-eliminable.
Of course, not every counterfactual scenario or relation is an idealization. Most counterfactuals, it seems, do not function to intentionally distort aspects of the world. In most counterfactuals there is ‘nothing counter to the facts’, for if certain conditions obtain, counterfactual relations become actual or true (cf. Ylikoski & Kuorikoski 2010).
However, descriptions of counterfactual organisms in design explanations are ‘counter to the facts’ and do intentionally distort aspects of the world. Features of extant organisms, i.e., specific traits, are purposefully misrepresented in order to make salient how specific traits of extant organisms make a difference to organismal fitness. Design explanations thus do more than highlight the explanatory role of contrasts with counterfactuals. In design explanations, distortions of facts are invoked to assess the biological advantage(s) of traits of extant organisms (cf. Wimsatt 2006).
Biologists are increasingly aware of the importance of robustness for understanding living systems (Kitano 2004; Stelling et al. 2004). Philosophers, too, increasingly recognize that there is more to robustness analysis than determining whether model predictions persist through changing assumptions about causal details of target systems. In particular, philosophers are beginning to recognize a form of robustness analysis directed toward determining whether model predictions persist though changing parameter values (which typically track details external to target systems). Call this kind of robustness parameter robustness, and say that a biological system is parameter-robust whenever it retains some particular feature across a wide range of parameter values. Biologists and philosophers are only recently starting to explore strategies for explaining why biological systems are parameter-robust. These strategies differ from each other with respect to their degree of causal specificity, and this difference tracks explanatory power. Specifically, strategies that depend least upon causal specifics also explain more about parameter-robustness. Or so I shall argue.
Support for my argument comes from a series of research papers about bacterial chemotaxis, and in particular a series of papers devoted to explaining why bacterial adaptation to changing chemical gradients is parameter robust. But while I rely primarily upon specific explanatory strategies for a specific explanatory interest, research on bacterial chemotaxis embodies a developing contrast between general explanatory strategies among molecular and cell biologists. I gesture toward this larger contrast as part of my concluding remarks. The argument, too, engages with some prima-facie unrelated philosophical literature, and in particular with Sober’s (1999) argument regarding “disunified” explanatory strategies—strategies that appeal to different details for different systems. Sober aims to show that certain “unified” explanations enjoy no explanatory superiority over their “disunified” counterparts. I argue that Sober overlooks how explanatory aims constrain explanatory quality.
I take this to be more than a quibble among philosophers about how to talk about what scientists are doing. Sober’s argument has been taken to support renewed reductionist ambitions (see Schaffner 2013). Biologists skeptical of the “unified” explanatory strategy often also take themselves to be reductionists of some sort; advocates take themselves to be resisting some kind of reductionism (see see Sorger 2005; Van Regenmortal 2004; Gatherer 2010). So there is philosophical value in better understanding how the unified strategy relates to its disunified cousins.
A central goal in science is to determine the best explanation for a given phenomenon. There are many strategies for doing this, including evaluating the empirical adequacy of the available hypotheses and assessing their relative epistemic virtues. In this talk, we examine one strategy for choosing between competing hypotheses employed in the fields of community ecology and comparative psychology. A central feature of this strategy is the use of what we call a “causal null hypothesis.” This is a hypothesis that practitioners in the field identify and treat in the same way that one would treat a statistical null hypothesis, but which lacks the features of a true statistical null. We present the ways in which causal and statistical null hypotheses differ and argue that an important consequence of these differences is that the strategy used for evaluating hypotheses in our cases studies is unjustified.
We begin by first showing how the appeal to null hypotheses is used in our case studies. It is used in community ecology to defend the neutral theory as the best explanation for species abundance distributions and in comparative psychology to defend the behavioral-rules account of social behavior in chimpanzees and other nonhuman animals. Both the neutral theory and behavioral-rules hypothesis are identified as “nulls” on the grounds that they are simpler than the alternatives available. These nulls are then privileged over the alternatives in that they are rendered both easier to accept and harder to reject. We show how this form of argument is superficially similar to the statistical method of Neyman-Pearson testing, thus giving it rhetorical force. However, we go on to argue that it is disanalogous in precisely those respects that are required for justification. Whereas the null hypotheses used in Neyman-Pearson testing are hypotheses of “no effect,” this is not the case for the null hypotheses in our case studies, which are both presented as positive, causal hypotheses by their proponents. Given this, we argue, the causal nulls identified in our cases studies should not be privileged over the alternatives, but treated on a par, and the rhetoric of testing null hypotheses should be dropped. In the end, we hope our analysis will stimulate critical discussions on the role that causal null hypothesis testing plays in other cases in science.
One caveat about the scope and purpose of our presentation: we are interested only in critiquing the causal null hypothesis strategy, not the specific hypotheses this strategy has been used to support. There may be better arguments or alternative lines of evidence that could be used to support the neutral theory and behavioral-rules hypothesis; we do not wish to deny that this is the case. Instead, our aim is to critique the argumentative strategy that depends on casting these hypotheses as nulls outside of the context of statistical hypothesis testing.
My paper aims to describe the relationship between the questions of philosophy of biology and the understanding/application of human rights. The discussion about this relationship affects how we understand what human rights are, what is their source of origin, and how we should apply them.
Evolutionary theory is usually assumed to be inconsistent with essentialist thinking. (According to essentialist thinking, certain categories, such as biological categories or human groups, have an underlying essential property that all and only the members of these categories possess.) This is because essentialist thinking stresses something that is common to all species members, whereas understanding natural selection as the main force underlying evolutionary change assumes accepting the variability between category members. However, paradoxically the explanations that appeal to evolutionary or biological factors often refer to something like functional universals that have evolved in the process of human evolution, presumably possessed by most members of a certain human group and being part of the characterization of that group. In this way evolutionary explanations themselves might become part of something like essentialist thinking about certain human groups (even human species as a whole), whereas naturally selected ‘functional universals’ are seen as a characteristic part of the essence of a group.
In my talk I will focus on the aspect of the relationship between biology and human rights that consists of the attempts of appealing to biological differences, group differences and human evolution when justifying the application of certain human rights. On the one hand, biological differences between individuals and groups have been seen as a counterargument against what is called the ‘egalitarian fallacy’ by some authors. According to these authors, equal rights are applied to many other things than what they meant in the Universal Declaration of Human Rights. Now, it is claimed, equal rights are coming to be considered ‘equal entitlements’. The basic reason for why this egalitarianism is unworkable, is a biological one, as each person differs genetically, experientally and in individual purposes and goals in life.
These seem like obviously anti-essentialist claims to make. However, appealing to biological and evolutionary factors when justifying the application of certain human rights might easily lead to making essentialist assumptions and inferences about certain human groups. In public discussions even in societies with egalitarian legislation we often hear arguments about how men and women, since they are biologically different and possess different naturally selected features, also have different interests and goals, which makes gender equality something like an artificial nonsense. Not only anti-egalitarians, but sometimes feminists themselves make somewhat essentialist assumptions about women – protecting the rights of certain groups often goes hand in hand with group essentialism. Another quite telling example is the arguments against gay marriages as something ‘unnatural’ – based on the assumption that gays cannot fulfil the normal evolutionary function of human species to reproduce with each other. In my presentation I will demonstrate how approaching these issues from the perspective of philosophy of biology can affect actual socio-political attitudes and applications concerning human rights.