Recent philosophical analyses of the epistemic dimension of images in the sciences show a certain trend in acknowledging potential roles of these images beyond their merely decorative or pedagogical functions. We argue, however, that this new debate has yet paid little attention to a special type of pictures, we call ‘visual metaphor’, and its versatile heuristic potential in organizing data, supporting communication, and guiding research, modeling, and theory formation. Based on a case study of Conrad Hal Waddington’s epigenetic landscape images (...) in biology, we develop a descriptive framework applicable to heuristic roles of various visual metaphors in the sciences. (shrink)

The two great modern naturalists, Linnaeus and Darwin, expressed their intuition about how best to visualize patterns of affinities, that is, morphological similarities and divergences between taxa. Linnaeus suggested that “all plants show affinities on all sides, like a territory on a geographical map,” while Darwin thought that it was virtually impossible to understand the affinities between living and extinct species without a genealogical tree. Genealogical trees follow the diachronic, evolving logic of a timeline, whereas maps depict a synchronous pattern (...) of extant taxa. Although the two seem unrelated, various naturalists made attempts to combine them. Surprisingly, these resulted in three-dimensional images that, in order to be observed, had to be projected on paper. The naturalists Max Fürbringer and Richard Bowdler Sharpe were aware of this fact, but even Darwin himself twice combined the basic intuitions underlying the two modes of representation to produce three-dimensional images. This article is a brief history of the efforts to merge genealogical trees and map-like cross sections of affinities into one three-dimensional image. (shrink)

Wright’s “adaptive landscape” has been influential in evolutionary thinking but controversial, especially because the landscape that organisms encounter is altered by the evolutionary process itsel...

The discussion of the adaptive landscape in the philosophical literature appears to be divided along the following lines. On the one hand, some claim that the adaptive landscape is either “uninterpretable” or incoherent. On the other hand, some argue that the adaptive landscape has been an important heuristic, or tool in the service of explaining, as well as proposing and testing hypotheses about evolutionary change. This paper attempts to reconcile these two views.

The concepts of adaptive/fitness landscapes and adaptive peaks are a central part of much of contemporary evolutionary biology; the concepts are introduced in introductory texts, developed in more detail in graduate-level treatments, and are used extensively in papers published in the major journals in the field. The appeal of visualizing the process of evolution in terms of the movement of populations on such landscapes is very strong; as one becomes familiar with the metaphor, one often develops the feeling that it (...) is possible to gain deep insights into evolution by thinking about the movement of populations on landscapes consisting of adaptive valleys and peaks. But, since Wright first introduced the metaphor in 1932, the metaphor has been the subject of persistent confusion, from equivocation over just what the features of the landscape are meant to represent to how we ought to expect the landscapes to look. Recent advances—conceptual, empirical, and computational—have pointed towards the inadequacy and indeed incoherence of the landscapes as usually pictured. I argue that attempts to reform the metaphor are misguided; it is time to give up the pictorial metaphor of the landscape entirely and rely instead on the results of formal modeling, however difficult such results are to understand in ‘intuitive’ terms. (shrink)

: Where there are cases of underdetermination in scientific controversies, such as the case of the molecular clock, scientists may direct the course and terms of dispute by playing off the multidimensional framework of theory evaluation. This is because assessment strategies themselves are underdetermined. Within the framework of assessment, there are a variety of trade-offs between different strategies as well as shifting emphases as specific strategies are given more or less weight in assessment situations. When a strategy is underdetermined, scientists (...) can change the dynamics of a controversy by making assessments using different combinations of evaluation strategies and/or weighting whatever strategies are in play in different ways. Following an underdetermination strategy does not end or resolve a scientific dispute. Consequently, manipulating underdetermination is a feature of controversy dynamics and not controversy closure. (shrink)

Path-dependence offers a promising way of understanding the role historicity plays in explanation, namely, how the past states of a process can matter in the explanation of a given outcome. The two main existing accounts of path-dependence have sought to present it either in terms of dynamic landscapes or branching trees. However, the notions of landscape and tree both have serious limitations and have been criticized. The framework of causal networks is both more fundamental and more general that that of (...) landscapes and trees. Within this framework, I propose that historicity in networks should be understood as symmetry breaking. History matters when an asymmetric bias towards an outcome emerges in a causal network. This permits a quantitative measure for how path-dependence can occur in degrees, and offers suggestive insights into how historicity is intertwined both with causal structure and complexity. (shrink)

Recently, much philosophical discussion has centered on the best way to characterize the concepts of random drift and natural selection, and, in particular, whether selection and drift can be conceptually distinguished (Beatty, 1984; Brandon, 2005; Hodge, 1983, 1987; Millstein, 2002, 2005; Pfeifer, 2005; Shanahan, 1992; Stephens, 2004). These authors all contend, to a greater or lesser degree, that their concepts make sense of biological practice. So it should be instructive to see how the concepts of drift and selection were distinguished (...) by the disputants in a high-profile debate; debates such as these often force biologists to take a more philosophical turn, discussing the concepts at issue in greater detail than usual. Moreover, it is important to consider a debate where the disputants are actually trying to apply the models of population genetics to natural populations; only then can their proper interpretations become fully apparent. (Indeed, I contend that some of the philosophical confusion has arisen because authors have considered only the models themselves, and not the phenomena that the models are attempting to represent). A prime candidate for just such a case study is what Provine (1986) has termed “The Great Snail Debate,” that is, the debates over the highly polymorphic land snails Cepaea nemoralis and C. hortensis in the 1950s and early 1960s. These studies represent one of the best, if not the best, of the early attempts to demonstrate drift in natural populations. (shrink)

We develop a new metaphor account where metaphors become surrogate variables for different but related phenomena. As we will argue, subrogation is the result of the interplay between the things inspired by the metaphor and the empirical dynamics that result from such inspiration. In particular, we focus on adaptive radiation, a major concept of evolutionary biology. Our study suggests that there is no distinct phenomenon, process, or pattern in nature than can be identified as adaptive radiation. What we have instead (...) is a grouping variable that has surrogated different evolutionary phenomena into one expansive label. We believe this analysis of metaphors helps better understand the value of metaphors for science not only as a provider of epistemic and cognitive virtues but most importantly, as a crucial research tool that can both help and divert scientific experimentation. (shrink)