Ernst Mayr proposed a distinction between “proximate”, mechanistic, and “ultimate”, evolutionary, causes of biological phenomena. This dichotomy has influenced the thinking of many biologists, but it is increasingly perceived as impeding modern studies of evolutionary processes, including study of “niche construction” in which organisms alter their environments in ways supportive of their evolutionary success. Some still find value for this dichotomy in its separation of answers to “how?” versus “why?”questions about evolution. But “why is A?” questions about evolution necessarily take (...) the form “how does A occur?”, so this separation is illusory. Moreover, the dichotomy distorts our view of evolutionary causality, in that, contra Mayr, the action of natural selection, driven by genotype-phenotype-environment interactions which constitute adaptations, is no less “proximate” than the biological mechanisms which are altered by naturally selected genetic variants. Mayr’s dichotomy thus needs replacement by more realistic, mechanistic views of evolution. From a mechanistic viewpoint, there is a continuum of adaptations from those evolving as responses to unchanging environmental pressures to those evolving as the capacity for niche construction, and intermediate stages of this can be identified. Some biologists postulate an association of “phenotypic plasticity” (phenotype-environment covariation with genotype held constant) with capacity for niche construction. Both “plasticity” and niche construction comprise wide ranges of adaptive mechanisms, often fully heritable and resulting from case-specific evolution. Association of “plasticity” with niche construction is most likely to arise in systems wherein capacity for complex learning and behavioral flexibility have already evolved. (shrink)

In 1961, Ernst Mayr published a highly influential article on the nature of causation in biology, in which he distinguished between proximate and ultimate causes. Mayr argued that proximate causes (e.g. physiological factors) and ultimate causes (e.g. natural selection) addressed distinct ‘how’ and ‘why’ questions and were not competing alternatives. That distinction retains explanatory value today. However, the adoption of Mayr’s heuristic led to the widespread belief that ontogenetic processes are irrelevant to evolutionary questions, a belief that has (1) hindered (...) progress within evolutionary biology, (2) forged divisions between evolutionary biology and adjacent disciplines and (3) obstructed several contemporary debates in biology. Here we expand on our earlier (Laland et al. in Science 334:1512–1516, 2011) argument that Mayr’s dichotomous formulation has now run its useful course, and that evolutionary biology would be better served by a concept of reciprocal causation, in which causation is perceived to cycle through biological systems recursively. We further suggest that a newer evolutionary synthesis is unlikely to emerge without this change in thinking about causation. (shrink)

In 1990 Robert Lickliter and Thomas Berry identified the phylogeny fallacy, an empirically untenable dichotomy between proximate and evolutionary causation, which locates proximate causes in the decoding of ‘ genetic programs’, and evolutionary causes in the historical events that shaped these programs. More recently, Lickliter and Hunter Honeycutt argued that Evolutionary Psychologists commit this fallacy, and they proposed an alternative research program for evolutionary psychology. For these authors the phylogeny fallacy is the proximate/evolutionary distinction itself, which they argue constitutes a (...) misunderstanding of development, and its role in the evolutionary process. In this article I argue that the phylogeny fallacy should be relocated to an error of reasoning that this causal framework sustains: the conflation of proximate and evolutionary explanation. Having identified this empirically neutral form of the phylogeny fallacy, I identify its mirror image, the ontogeny fallacy. Through the lens of these fallacies I attempt to solve several outstanding problems in the debate that ensued from Lickliter and Honeycutt’s provocative article. (shrink)

Within evolutionary biology a distinction is frequently made between proximate and ultimate causes. One apparently plausible interpretation of this dichotomy is that proximate causes concern processes occurring during the life of an organism while ultimate causes refer to those processes (particularly natural selection) that shaped its genome. But ultimate causes are not sought through historical investigations of an organisms lineage. Rather, explanations referring to ultimate causes typically emerge from functional analyses. But these functional analyses do not identify causes of any (...) kind, much less ultimate ones. So-called ultimate explanations are not about causes in any sense resembling those of proximate explanations. The attitude, implicit in the term ultimate cause, that these functional analyses are somehow superordinate to those involving proximate causes is unfounded. Ultimate causes are neither ultimate nor causes. (shrink)

Laland and colleagues have sought to challenge the proximate–ultimate distinction claiming that it imposes a unidirectional model of causation, is limited in its capacity to account for complex biological phenomena, and hinders progress in biology. In this article the core of their argument is critically analyzed. It is claimed that contrary to their claims Laland et al. rely upon the proximate–ultimate distinction to make their points and that their alternative conception of reciprocal causation refers to phenomena that were already accounted (...) for by standard theory. (shrink)

Ernst Mayr''s distinction between ultimate and proximate causes is justly considered a major contribution to philosophy of biology. But how did Mayr come to this philosophical distinction, and what role did it play in his earlier scientific work? I address these issues by dividing Mayr''s work into three careers or phases: 1) Mayr the naturalist/researcher, 2) Mayr the representative of and spokesman for evolutionary biology and systematics, and more recently 3) Mayr the historian and philosopher of biology. If we want (...) to understand the role of the proximate/ultimate distinction in Mayr''s more recent career as a philosopher and historian, then it helps to consider hisearlier use of the distinction, in the course of his research, and in his promotion of the professions of evolutionary biology and systematics. I believe that this approach would also shed light on some other important philosophical positions that Mayr has defended, including the distinction between essentialism: and population thinking. (shrink)

Darwin’s theory of evolution by natural selection unifies the world of physics with the world of meaning and purpose by proposing a deeply counterintuitive ‘‘inversion of reasoning’’ (according to a 19th century critic): ‘‘to make a perfect and beautiful machine, it is not requisite to know how to make it’’ [MacKenzie RB (1868) (Nisbet & Co., London)]. Turing proposed a similar inversion: to be a perfect and beautiful computing machine, it is not requisite to know what arithmetic is. Together, these (...) ideas help to explain how we human intelligences came to be able to discern the reasons for all of the adaptations of life, including our own. (shrink)