Grant Ramsey

A New Foundation for the Propensity Interpretation of Fitness

The propensity interpretation of fitness (PIF) is commonly taken to be subject to a set of simple counterexamples. We argue that three of the most important of these are not counterexamples to the PIF itself, but only to the traditional mathematical model of this propensity: fitness as expected number of offspring. They fail to demonstrate that a new mathematical model of the PIF could not succeed where this older model fails. We then propose a new formalization of the PIF that avoids these (and other) counterexamples. By producing a counterexample-free model of the PIF, we call into question one of the primary motivations for adopting the statisticalist interpretation of fitness. In addition, this new model has the benefit of being more closely allied with contemporary mathematical biology than the traditional model of the PIF. 1 Introduction   1.1 The ‘Generality Problem’   1.2 Counterexamples to the PIF    1.2.1 The moments problem    1.2.2 The delayed selection problem    1.2.3 Timing of reproduction   1.3 The need for a new model 2 A New Formalization   2.1 The new model and biological theory 3 Possible Objections to   3.1 Objection 1: Natural selection is short term   3.2 Objection 2: Descendants are only minimally related to ancestors   3.3 Objection 3: Evolutionary time scale is pragmatically determined   3.4 Objection 4: Long-term fitness is lineage fitness   3.5 Objection 5: The theory of evolution by natural selection fundamentally concerns trait fitness, not individual fitness 4 Response to Counterexamples   4.1 Timing of reproduction   4.2 Delayed selection   4.3 The moments problem 5 Conclusion 1 Introduction   1.1 The ‘Generality Problem’   1.2 Counterexamples to the PIF    1.2.1 The moments problem    1.2.2 The delayed selection problem    1.2.3 Timing of reproduction   1.3 The need for a new model   1.1 The ‘Generality Problem’   1.2 Counterexamples to the PIF    1.2.1 The moments problem    1.2.2 The delayed selection problem    1.2.3 Timing of reproduction    1.2.1 The moments problem    1.2.2 The delayed selection problem    1.2.3 Timing of reproduction   1.3 The need for a new model 2 A New Formalization   2.1 The new model and biological theory   2.1 The new model and biological theory 3 Possible Objections to   3.1 Objection 1: Natural selection is short term   3.2 Objection 2: Descendants are only minimally related to ancestors   3.3 Objection 3: Evolutionary time scale is pragmatically determined   3.4 Objection 4: Long-term fitness is lineage fitness   3.5 Objection 5: The theory of evolution by natural selection fundamentally concerns trait fitness, not individual fitness   3.1 Objection 1: Natural selection is short term   3.2 Objection 2: Descendants are only minimally related to ancestors   3.3 Objection 3: Evolutionary time scale is pragmatically determined   3.4 Objection 4: Long-term fitness is lineage fitness   3.5 Objection 5: The theory of evolution by natural selection fundamentally concerns trait fitness, not individual fitness 4 Response to Counterexamples   4.1 Timing of reproduction   4.2 Delayed selection   4.3 The moments problem   4.1 Timing of reproduction   4.2 Delayed selection   4.3 The moments problem 5 Conclusion

Human nature in a post-essentialist world

In this essay I examine a well-known articulation of human nature skepticism, a paper by Hull. I then review a recent reply to Hull by Machery, which argues for an account of human nature that he claims is both useful and scientifically robust. I challenge Machery’s account and introduce an alternative account—the “life-history trait cluster” conception of human nature—that I hold is scientifically sound and makes sense of (at least some of) our intuitions about—and desiderata for—human nature.

Sameness in Biology

Homology is a biological sameness relation that is purported to hold in the face of changes in form, composition, and function. In spite of the centrality and importance of homology, there is no consensus on how we should understand this concept. The two leading views of homology, the genealogical and developmental accounts, have significant shortcomings. We propose a new account, the hierarchical-dependency account of homology, which avoids these shortcomings. Furthermore, our account provides for continuity between special, general, and serial homology.

Organisms, Traits, and Population Subdivisions: Two Arguments against the Causal Conception of Fitness?

A major debate in the philosophy of biology centers on the question of how we should understand the causal structure of natural selection. This debate is polarized into the causal and statistical positions. The main arguments from the statistical side are that a causal construal of the theory of natural selections central concept, fitness, either (i) leads to inaccurate predictions about population dynamics, or (ii) leads to an incoherent set of causal commitments. In this essay, I argue that neither the predictive inaccuracy nor the incoherency arguments successfully undermine the causal account of fitness. 1 Introduction 2 The Importance of Trait Fitness 3 Trait Fitness is not a Silver Bullet 4 The Fundamental Incoherency Argument 5 Car Racing and Trait Fitness Reversals 6 Population Subdivisions and Evolution 7 The STP and the Argument for the Incoherency of the Causal Account of Fitness 8 Conclusions 1 Introduction 2 The Importance of Trait Fitness 3 Trait Fitness is not a Silver Bullet 4 The Fundamental Incoherency Argument 5 Car Racing and Trait Fitness Reversals 6 Population Subdivisions and Evolution 7 The STP and the Argument for the Incoherency of the Causal Account of Fitness 8 Conclusions

Is Cultural Fitness Hopelessly Confused

Fitness is a central concept in evolutionary theory. Just as it is central to biological evolution, so, it seems, it should be central to cultural evolutionary theory (CET). But importing the biological fitness concept to CET is no straightforward task—there are many features unique to cultural evolution that make this difficult. This has led some theorists to argue that there are fundamental problems with cultural fitness that render it hopelessly confused. In this essay, we defend the coherency of cultural fitness against those who call it into doubt. 1. Introduction2. Cultural Fitness is Not Superfluous3. The Individuation Problem 3.1. The generations problem3.2. Cultural growth versus cultural reproduction4. The Repeated Learning Problem 4.1. The retention problem4.2. Is fitness transitive?5. Towards a Concept of Cultural Fitness 5.1. Biological and cultural individuals5.2. Mutation and transmission biases6. Conclusions Introduction Cultural Fitness is Not Superfluous The Individuation Problem 3.1. The generations problem3.2. Cultural growth versus cultural reproduction The generations problem Cultural growth versus cultural reproduction The Repeated Learning Problem 4.1. The retention problem4.2. Is fitness transitive? The retention problem Is fitness transitive? Towards a Concept of Cultural Fitness 5.1. Biological and cultural individuals5.2. Mutation and transmission biases Biological and cultural individuals Mutation and transmission biases Conclusions

On the concept of animal innovation and the challenge of studying innovation in the wild

The commentaries have both drawn out the implications of, and challenged, our definition and operationalization of innovation. In this response, we reply to these concerns, discuss the differences between our operationalization and the preexisting operationalization if innovation, and make suggestions for the advancement of the challenging and exciting field of animal innovation.

evoText: A new tool for analyzing the biological sciences

We introduce here evoText, a new tool for automated analysis of the literature in the biological sciences. evoText contains a database of hundreds of thousands of journal articles and an array of analysis tools for generating quantitative data on the nature and history of life science, especially ecology and evolutionary biology. This article describes the features of evoText, presents a variety of examples of the kinds of analyses that evoText can run, and offers a brief tutorial describing how to use it.

Can altruism be unified

There is clearly a plurality of forms of altruism. Classically, biological altruism is distinguished from psychological altruism. Recent discussions of altruism have attempted to distinguish even more forms of altruism. I will focus on three altruism concepts, biological altruism, psychological altruism, and helping altruism. The questions I am concerned with here are, first, how should we understand these concepts? and second, what relationship do these concepts bear to one another? In particular, is there an essence to altruism that unifies these concepts? I suggest that while there is no essence to altruism, this does not mean that the array of altruism concepts is completely disunified. Instead, I propose we place all the concepts into a common framework-an altruism space-that could lead to new questions about how this space can be filled.

Guilt by association

Abstract Recent evolutionary perspectives on guilt tend to focus on how guilt functions as a means for the individual to self-regulate behavior and as a mechanism for reinforcing cooperative tendencies. While these accounts highlight important dimensions of guilt and provide important insights into its evolutionary emergence, they pay scant attention to the large empirical literature on its maladaptive effects on individuals. This paper considers the nature of guilt, explores its biological function, and provides an evolutionary perspective on whether it is an individual-level or group selected trait. After surveying philosophical and psychological analyses of guilt, we consider which psychological mechanisms underlie the capacity to experience and act from guilt and whether they point to an emergence of guilt in early humans or to guilt having a longer phylogenetic history. Because guilt is a characteristically social emotion, we then examine its contemporary role in social and legal contexts, which may provide clues to its original biological function. Finally, we provide the outlines of two evolutionary explanations for guilt. We argue that group selection may have promoted the capacity to experience guilt, but that under certain conditions there may have been a positive individual selection force as well.

The Causal Structure of Evolutionary Theory

ABSTRACT One contentious debate in the philosophy of biology is that between the statisticalists and causalists. The former understand core evolutionary concepts like fitness and selection to be mere statistical summaries of underlying causal processes. In this view, evolutionary changes cannot be causally explained by selection or fitness. The causalist side, on the other hand, holds that populations can change in response to selection—one can cite fitness differences or driftability in causal explanations of evolutionary change. But, on the causalist side, it is often not clear how, precisely, one should understand these causes. Thus, much more could be said about what sort of causes fitness and driftability are. In this paper, I borrow Dretskes distinction between structuring and triggering causes and I suggest that fitness and driftability are structuring causes of evolution.