The mirror of physics: on how the Price equation can unify evolutionary biology

Abstract

Due to its high degree of complexity and its historical nature, evolutionary biology has been traditionally portrayed as a messy science. According to the supporters of such a view, evolutionary biology would be unable to formulate laws and robust theories, instead just delivering coherent narratives and local models. In this article, our aim is to challenge this view by showing how the Price equation can work as the core of a general theoretical framework for evolutionary phenomena. To support this claim, we outline some unnoticed structural similarities between physical theories (in particular, classical mechanics) and evolutionary biology. More specifically, we shall argue that the Price equation, in the same way as fundamental formalisms in physics, can serve as a heuristic principle to formulate and systematise different theories and models in evolutionary biology.

What is the price of using the Price equation in ecology?

“…To quote Luque (2017): 'the Price equation implies a very specific way of theorizing, starting with assumptions that we think are true and then deriving from them the mathematical rules of the system.' Similar statements are found in Frank (2012), Lion (2018), Luque and Baravalle (2021) and Queller (2017).…”

“…According to some philosophers (Kitcher 1989), and I agree with them, there is room in science for such unification principles. The Price equation is a good contender for being one such principle (Luque 2017, Luque and Baravalle 2021). For the ‘against camp,' the equation has a very specific form and ought to represent something akin to a dynamical model yielding predictions that can be refuted.…”

Towards a Pricean foundation for cultural evolutionary theory

“…Rather than being directly applicable to model specific scenarios, it works as a versatile heuristic tool to formulate new hypotheses about the phenomena under study, as well as to find out new equations describing these more specific scenarios. The Price equation can be considered the fundamental law of evolution (Luque, 2017;Queller, 2017;Luque and Baravalle, 2021) insofar as it does not commit us to any unequivocal view about the causes of evolution, but it identifies those concepts and dynamical features that any evolutionary approach to a certain domain of phenomena must assume. Cultural evolutionary theory is an expanding area of research.…”

“…If we compare the Price equation to other "fundamental laws" in physics and biology, like Newton's second law or the "principle of natural selection" (Brandon, 1982), we can easily appreciate that they all are merely consequence laws (Sober, 1984) -that is, they do not have a causal import-and they are almost empirical vacuous (Díez and Lorenzano, 2013) -i.e., they are little more than identities. Therefore, what the critics consider a defect of the Price equation is, on the contrary, a trait that this equation shares with some of the most important laws in the history of science (Luque, 2017;Luque and Baravalle, 2021). It is what Kuhn (1970) called a "generalisation-sketch" and Moulines (1984) a "guiding-principle": a heuristic principle that provides a working scheme for developing the further details of the theory.…”

Model-Based Estimates for Operant Selection

“…For example, when applied to the evolutionary change of gene frequencies, the residual term captures the effects of imperfect transmission (i.e., mutation and recombination). When applied to phenotypic change over generations (e.g., body weight or behavioral traits), the term may also capture environmental factors influencing the phenotype (Luque & Baravalle, 2021).…”