University of Wisconsin, Madison
Department of Philosophy
PhD, 2008
Lubbock, Texas, United States of America
Areas of Specialization
Philosophy of Biology
  •  246
    Updating on the Credences of Others: Disagreement, Agreement, and Synergy
    with Kenny Easwaran, Luke Fenton-Glynn, and Christopher Hitchcock
    Philosophers’ Imprint 16 1--39. 2016.
    We introduce a family of rules for adjusting one's credences in response to learning the credences of others. These rules have a number of desirable features. 1. They yield the posterior credences that would result from updating by standard Bayesian conditionalization on one's peers' reported credences if one's likelihood function takes a particular simple form. 2. In the simplest form, they are symmetric among the agents in the group. 3. They map neatly onto the familiar Condorcet voting result…Read more
  •  164
    A natural starting place for developing a phylogenetic species concept is to examine monophyletic groups of organisms. Proponents of “the” Phylogenetic Species Concept fall into one of two camps. The first camp denies that species even could be monophyletic and groups organisms using character traits. The second groups organisms using common ancestry and requires that species must be monophyletic. I argue that neither view is entirely correct. While monophyletic groups of organisms exist, they s…Read more
  •  136
    Species concepts should not conflict with evolutionary history, but often do
    Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 39 (4): 407-414. 2008.
    Many phylogenetic systematists have criticized the Biological Species Concept (BSC) because it distorts evolutionary history. While defenses against this particular criticism have been attempted, I argue that these responses are unsuccessful. In addition, I argue that the source of this problem leads to previously unappreciated, and deeper, fatal objections. These objections to the BSC also straightforwardly apply to other species concepts that are not defined by genealogical history. What is mi…Read more
  •  135
    A phylogeny that allows for lateral gene transfer (LGT) can be thought of as a strictly branching tree (all of whose branches are vertical) to which lateral branches have been added. Given that the goal of phylogenetics is to depict evolutionary history, we should look for the best supported phylogenetic network and not restrict ourselves to considering trees. However, the obvious extensions of popular tree-based methods such as maximum parsimony and maximum likelihood face a serious problem—if …Read more
  •  106
    Deep Conventionalism about Evolutionary Groups
    Philosophy of Science 80 (5): 971-982. 2013.
    We argue for a new conventionalism about many kinds of evolutionary groups, including clades, cohesive units, and populations. This rejects a consensus, which says that given any one of the many legitimate grouping concepts, only objective biological facts determine whether a collection is such a group. Surprisingly, being any one kind of evolutionary group typically depends on which of many incompatible values are taken by suppressed variables. This is a novel pluralism underlying most any one …Read more
  •  92
    The prior probabilities of phylogenetic trees
    Biology and Philosophy 23 (4): 455-473. 2008.
    Bayesian methods have become among the most popular methods in phylogenetics, but theoretical opposition to this methodology remains. After providing an introduction to Bayesian theory in this context, I attempt to tackle the problem mentioned most often in the literature: the “problem of the priors”—how to assign prior probabilities to tree hypotheses. I first argue that a recent objection—that an appropriate assignment of priors is impossible—is based on a misunderstanding of what ignorance an…Read more
  •  80
    Species, Genes, and the Tree of Life
    British Journal for the Philosophy of Science 61 (3): 599-619. 2010.
    A common view is that species occupy a unique position on the Tree of Life. Evaluating this claim requires an understanding of what the Tree of Life represents. The Tree represents history, but there are at least three biological levels that are often said to have genealogies: species, organisms, and genes. Here I focus on defending the plausibility of a gene-based account of the Tree. This leads to an account of species that are determined by gene genealogies. On this view, an exclusive group i…Read more
  •  76
    Evolutionary and Newtonian Forces
    Ergo: An Open Access Journal of Philosophy 1 39-77. 2014.
    A number of recent papers have criticized what they call the dynamical interpretation of evolutionary theory found in Elliott Sober’s The Nature of Selection. Sober argues that we can think of evolutionary theory as a theory of forces analogous to Newtonian mechanics. These critics argue that there are several important disanalogies between evolutionary and Newtonian forces: Unlike evolutionary forces, Newtonian forces can be considered in isolation, they have source laws, they compose causally …Read more
  •  71
    Phylogeny as population history
    Philosophy, Theory, and Practice in Biology 5. 2013.
    The project of this paper is to understand what a phylogenetic tree represents and to discuss some of the implications that this has for the practice of systematics. At least the first part of this task, if not both parts, might appear trivial—or perhaps better suited for a single page in a textbook rather than a scholarly research paper. But this would be a mistake. While the task of interpreting phylogenetic trees is often treated in a trivial way, their interpretation is tied to foundational …Read more
  •  58
    Towards a semantics for metanormative constructivism
    Philosophical Studies 176 (11): 3061-3076. 2019.
    The status of constructivism as a metaethical or metanormative theory is unclear partly due to the lack of a clear semantics for central normative terms such as ‘reason’ and ‘ought’. In a series of recent papers, Sharon Street has attempted to clarify the central commitments of constructivism by focusing on the idea of a practical point of view and what follows from it. We improve upon the informal understanding provided by Street and attempt to provide a semantics for ‘ought’. Our semantics res…Read more
  •  55
    The wide scope of philosophy of biology Content Type Journal Article Category Book Review Pages 1-4 DOI 10.1007/s11016-011-9619-0 Authors Joel D. Velasco, Division of Humanities and Social Sciences, California Institute of Technology, MC 101-40, Pasadena, CA 91125, USA Journal Metascience Online ISSN 1467-9981 Print ISSN 0815-0796
  •  51
    Philosophy and Phylogenetics
    Philosophy Compass 8 (10): 990-998. 2013.
    Phylogenetics is the study and reconstruction of evolutionary history and is filled with numerous foundational issues of interest to philosophers. This paper briefly introduces some central concepts in the field, describes some of the main methods for inferring phylogenies, and provides some arguments for the superiority of model-based methods such as Likelihood and Bayesian methods over nonparametric methods such as parsimony. It also raises some underdeveloped issues in the field of interest t…Read more
  •  51
    Objective and Subjective Probability in Gene Expression
    Progress in Biophysics and Molecular Biology 110 5-10. 2012.
    In this paper I address the question of whether the probabilities that appear in models of stochastic gene expression are objective or subjective. I argue that while our best models of the phenomena in question are stochastic models, this fact should not lead us to automatically assume that the processes are inherently stochastic. After distinguishing between models and reality, I give a brief introduction to the philosophical problem of the interpretation of probability statements. I argue that…Read more
  •  45
    Ockham’s Razors: A User’s Manual, by Elliott Sober (review)
    Mind 127 (507): 891-902. 2018.
    Mind Association 2017Elliott Sober’s first book, Simplicity, defends the view that the simplicity of a theory or hypothesis is a measure of its informativeness – roughly, simpler theories require less new information to be added to them to answer relevant questions of interest. While this measure of simplicity is question-relative, it is still what you might call a global view of simplicity – simplicity means the same thing across different scientific problems and it is always an epistemic virtu…Read more
  •  39
    The Species Problem
    Philosophical Review 120 (4): 598-602. 2011.
  •  34
    The Future of Systematics: Tree Thinking without the Tree
    Philosophy of Science 79 (5): 624-636. 2012.
    Phylogenetic trees are meant to represent the genealogical history of life and apparently derive their justification from the existence of the tree of life and the fact that evolutionary processes are treelike. However, there are a number of problems for these assumptions. Here it is argued that once we understand the important role that phylogenetic trees play as models that contain idealizations, we can accept these criticisms and deny the reality of the tree while justifying the continued use…Read more
  •  21
    Common ancestry is a central feature of the theory of evolution, yet it is not clear what “common ancestry” actually means; nor is it clear how it is related to other terms such as “the Tree of Life” and “the last universal common ancestor”. I argue these terms describe three distinct hypotheses ordered in a logical way: that there is a Tree of Life is a claim about the pattern of evolutionary history, that there is a last universal common ancestor is an ontological claim about the existence of …Read more
  •  16
    The Foundations of Concordance Views of Phylogeny
    Philosophy, Theory, and Practice in Biology 11. 2019.
    Despite the enormous importance and widespread use of the term, it is unclear exactly what a phylogeny represents. It is important to define phylogeny precisely since other central terms like “clade” and “monophyletic” are often defined relative to phylogenetic trees and on some views in taxonomy, taxa must be clades. Edwards presents the common picture in contemporary systematics as depending on the existence of a “species tree” in which phylogeny “records the branching pattern of evolving line…Read more