The article reevaluates the distinction between experiment and observation. It is first argued that to get clear on what role observation plays in the generation of scientific knowledge, we need to distinguish “experiential observation” as a concept closely connected to experience from “observation” in a technical sense and from “field observation” as a concept that reasonably contrasts with “experiment.” It is then argued that observation construed as field observation can enjoy systematic epistemic advantages over experiment, contrary to appearances.

This article first poses a skeptical challenge to clinical trials in medicine. The efficacy of treatments is measured against placebo, but placebo responses are not constant. They fluctuate with demographic variables, and they seem to be increasing over time. We therefore find ourselves measuring with the equivalent of what Wittgenstein termed an “elastic ruler.”

I then propose a “skeptical solution” to the problem. Elastic rulers are suitable tools for measuring dynamic, floating networks of values, like foreign currency exchanges. We can assuage the skeptical concerns by understanding clinical trials in this way; I suggest several practical guidelines for doing so.

Darwin describes the Origin of Species as ‘one long argument’. The exact structure of this argument has been the subject of controversy among philosophers of biology. I will propose a novel analysis that sheds new light on Darwin’s argument. The central claim will be that the evidence that supports the theory of common descent can only satisfactorily support it after the theory of natural selection has been regarded as an in principle possibility. This account helps us understand some enigmatic features of the structure of the Origin and has consequences for evidentialism and Bayesianism as applied to Darwin’s argument.

Justin Garson has argued, contrary to the claims of proponents of purportedly ahistorical theories of functions, that there are no ahistorical theories of functions. In the interest of satisfying uncontroversial desiderata on a theory of functions, the most influential ahistorical views all smuggle in history. I argue that Garson’s case relies on a misinterpretation of the ahistorical accounts he targets and that the details of the misinterpretation are instructive. They highlight often unquestioned assumptions about how a theory of functions fits into a broader account of scientific practice and what theoretical work a definition of function should do.

Eugenic arguments are not a thing of the past. In 2016, geneticist Michael Lynch published an article in Genetics arguing that human mental and physical performance are declining at a rate of 1% per generation. This estimate is not based on measurements of performance but on an argument from mutational load: Medical interventions are relaxing selection on the human population, which will lead to a buildup of deleterious mutations. This simple argument from mutational load is invalid. When the argument is made valid, it is not obvious that there are any significant consequences for human population health.

Stegenga (forthcoming) formulates and defends a novel account of scientific progress, according to which science makes progress just in case there is a change in scientific justification. Here, we present several problems for Stegenga’s account, concerning, respectively, (i) obtaining misleading evidence, (ii) losses or destruction of evidence, (iii) oscillations in scientific justification, and (iv) the possibility of scientific regress. We conclude by sketching a substantially different justification-based account of scientific progress that avoids these problems.

Philosophers of science have overlooked the role of theory in neuroscience, resulting in a somewhat surprising naïveté regarding the nature and function of neuroscientific theories. Here I provide a framework that identifies and begins to characterize what we need to know about neuroscientific theories so as to improve our epistemic standing. I argue that we need an account of the structural, interpretive, and functional aspects of neuroscientific theories, using the neuron doctrine as an illustrative case study. I introduce the novel metaphor of theoretical infrastructure as a guide for making sense of neuroscientific theories and their place within neuroscientific practice.

According to Jerome Wakefield’s harmful dysfunction account, a mental disorder must involve an objective dysfunction couched in evolutionary terms. However, selected effects functions are indeterminate because (i) the same trait can be both selectively advantageous and disadvantageous, and (ii) the functional activity of a trait can be assessed according to conflicting norms, given the trait’s place in a hierarchy of functions. Therefore, there may be a dysfunction that can be described in multiple empirically adequate ways. The choices involved in these cases are value-laden. Some cases of addiction may fit this mold, involving indeterminacy that invites opposing value judgments.