Recent work on inheritance systems can be divided into inclusive conceptions, according to which genetic and non-genetic inheritance are both involved in the development and transmission of nearly all animal behavioral traits, and more demanding conceptions of what it takes for non-genetic resources involved in development to qualify as a distinct inheritance system. It might be thought that, if a more stringent conception is adopted, homologies could not subsist across two distinct inheritance systems. Indeed, it is commonly assumed that homology (...) relations cannot survive a shift between genetic and cultural inheritance systems, and substantial reliance has been placed on that assumption in debates over the phylogenetic origins of hominin behavioral traits, such as male-initiated intergroup aggression. However, in the homology literature it is widely accepted that a trait can be homologous—that is, inherited continuously in two different lineages from a single common ancestor—despite divergence in the mechanisms involved in the trait’s development in the two lineages. In this paper, we argue that even on an extremely stringent understanding of what it takes for developmental resources to form a separate inheritance system, homologies can nonetheless subsist across shifts between distinct inheritance systems. We argue that this result is a merit of this way of characterizing what it is to be an inheritance system, that it has implications for adjudicating between alternative accounts of homology, and that it offers an important cautionary lesson about how to reason with the homology concept, particularly in the context of cultural species. (shrink)

Many of the existing ethical analyses of genetic engineering technologies (GET) focus on how they can be used to enhance individuals—to improve individual well-being, health and cognition. There is a gap in the current literature about the specific ways enhancement technologies could be used to improve our populations and species, viewed as a whole. In this paper, I explore how GET may be used to enhance the species through improvements in the gene pool. I argue one aspect of the species (...) that may be desirable to enhance is ‘persistence’ or long-term viability. I then look at some of the ways in which GET could be used to improve human persistence and argue that the use of GET to secure benefits for individuals may compromise persistence. This suggests conflicts between uses of GET to enhance individuals and uses to promote the persistence of the species may occur. As GET are further developed, the likelihood that these conflicts will actually arise, and how we should resolve them if they do, will need to be considered. (shrink)

One argument which is frequently levelled against the enhancement of human biology is that we do not understand the evolved function of our bodies well enough to meddle in our biology without producing unintended and potentially catastrophic effects. In particular, this argument is levelled against attempts to slow or eliminate the processes of human ageing, or ‘senescence’, which cause us to grow decrepit before we die. In this article, I claim that even if this argument could usefully be applied against (...) attempts to enhance other human traits, it cannot be valid in the case of attempts to enhance the various processes that constitute senescence. I begin by reviewing the biology of ageing to show how it consists of a number of unrelated traits. Then, following the arguments of a number of evolutionary biologists, I explain that every one of these traits is a product of evolutionary ‘neglect’ rather than ‘intent’. Finally, I consider the strongest version of the argument against enhancing senescence, which acknowledges these facts about the evolution of ageing but insists that we have nevertheless have prudential reasons to avoid enhancement wherever there is some uncertainty about the genetics or evolutionary function of a trait. I provide two reasons for rejecting this version of the argument as well, even in the case of human senescence, where such uncertainty is currently significant. (shrink)

One argument that is sometimes made against pursuing radical forms of human life extension is that such interventions will make the species less evolvable, which would be morally undesirable. In this article, I discuss the empirical and evaluative claims of this argument. I argue that radical increases in life expectancy could, in principle, reduce the evolutionary potential of human populations through both biological and cultural mechanisms. I further argue that if life extension did reduce the evolvability of the species, this (...) will be undesirable for three reasons: it may increase the species’ susceptibility to extinction risks, it may adversely affect institutions and practices that promote well-being, and it may impede moral progress. (shrink)