The plasticity of ageing and the rediscovery of ground-state prevention

Is ageing undesirable? An ethical analysis

The technical possibilities of biomedicine open up the opportunity to intervene in ageing itself with the aim of mitigating, reducing or eliminating it. However, before undertaking these changes or rejecting them outright, it is necessary to ask ourselves if what would be lost by doing so really has much value. This article will analyse the desirability of ageing from an individual point of view, without circumscribing this question to the desirability or undesirability of death. First, we will present the three most widely used arguments to reject biomedical interventions against ageing. We will argue that only the last of these arguments provides a consistent answer to the question of the desirability of ageing. Second, we will show that the third argument falls prey to a conceptual confusion that we will call the paradox of ageing: although ageing entails negative health effects, it leads to a life stage with valuable goods. Both valuations, one positive and the other negative, refer to two different dimensions of ageing: the chronological and the biological. We will defend that, by not adequately distinguishing these two types of ageing, it does not become apparent that all the valuable goods exclusive to ageing derive only from its chronological dimension. Third, we will argue that, if we just conceive ageing biologically, it is undesirable. We will elaborate on the two kinds of undesirable effects biological ageing has: direct and indirect. Finally, we will respond to potential objections by adducing that these are insufficient to weaken our argument.

Slowing down decay: biological clocks in personalized medicine

This article discusses so-called biological clocks. These technologies, based on aging biomarkers, trace and measure molecular changes in order to monitor individuals' "true" biological age against their chronological age. Drawing on the concept of decay, and building on ethnographic fieldwork in an academic laboratory and a commercial firm, we analyze the implications of the development and commercialization of biological clocks that can identify when decay is "out of tempo." We show how the building of biological clocks rests on particular forms of knowing decay: In the academic laboratory, researchers focus on endo-processes of decay that are internal to the person, but when the technology moves to the market, the focus shifts as staff bracket decay as exo-processes, which are seen as resulting from a person's lifestyle. As the technology of biological clocks travels from the laboratory to the market of online testing of the consumer's biological age, we observe shifting visions of aging: from an inevitable trajectory of decline to a malleable and plastic one. While decay is an inevitable trajectory starting at birth and ending with death, the commercialization of biological clocks points to ways of stretching time between birth and death as individuals "optimize" their biological age through lifestyle changes. Regardless of admitted uncertainties about what is measured and the connection between maintenance and future health outcomes, the aging person is made responsible for their decaying body and for enacting maintenance to slow down decay. We show how the biological clock's way of "knowing" decay turns aging and its maintenance into a life-long concern and highlight the normative implications of framing decay as malleable and in need of intervention.

Medawar and Hamilton on the selective forces in the evolution of ageing

Both Medawar and Hamilton contributed key ideas to the modern evolutionary theory of ageing. In particular, they both suggested that, in populations with overlapping generations, the force with which selection acts on traits declines with the age at which traits are expressed. This decline would eventually cause ageing to evolve. However, the biological literature diverges on the relationship between Medawar's analysis of the force of selection and Hamilton's. Some authors appear to believe that Hamilton perfected Medawar's insightful, yet ultimately erroneous analysis of this force, while others see Hamilton's analysis as a coherent development of, or the obvious complement to Medawar's. Here, the relationship between the two analyses is revisited. Two things are argued for. First, most of Medawar's alleged errors that Hamilton would had rectified seem not to be there. The origin of these perceived errors appears to be in a misinterpretation of Medawar's writings. Second, the mathematics of Medawar and that of Hamilton show a significant overlap. However, different meanings are attached to the same mathematical expression. Medawar put forth an expression for the selective force on age-specific fitness. Hamilton proposed a full spectrum of selective forces each operating on age-specific fitness components, i.e. mortality and fertility. One of Hamilton's expressions, possibly his most important, is of the same form as Medawar's expression. But Hamilton's selective forces on age-specific fitness components do not add up to yield Medawar's selective force on age-specific fitness. It is concluded that Hamilton's analysis should be considered neither as a correction to Medawar's analysis nor as its obvious complement.

Aging biomarkers and the measurement of health and risk

Prevention of age-related disorders is increasingly in focus of health policies, and it is hoped that early intervention on processes of deterioration can promote healthier and longer lives. New opportunities to slow down the aging process are emerging with new fields such as personalized nutrition. Data-intensive research has the potential to improve the precision of existing risk factors, e.g., to replace coarse-grained markers such as blood cholesterol with more detailed multivariate biomarkers. In this paper, we follow an attempt to develop a new aging biomarker. The vision among the project consortium, comprising both research and industrial partners, is that the new biomarker will be predictive of a range of age-related conditions, which may be preventable through personalized nutrition. We combine philosophical analysis and ethnographic fieldwork to explore the possibilities and challenges of managing aging through bodily signs that are not straightforwardly linked to symptomatic disease. We document how the improvement of measurement brings about new conceptual challenges of demarcating healthy and unhealthy states. Moreover, we highlight that the reframing of aging as risk has social and ethical implications, as it is generative of normative notions of what constitutes successful aging and good citizenship.

Aging biomarkers and the measurement of health and risk

Prevention of age-related disorders is increasingly in focus of health policies, and it is hoped that early intervention on processes of deterioration can promote healthier and longer lives. New opportunities to slow down the aging process are emerging with new fields such as personalized nutrition. Data-intensive research has the potential to improve the precision of existing risk factors, e.g., to replace coarse-grained markers such as blood cholesterol with more detailed multivariate biomarkers. In this paper, we follow an attempt to develop a new aging biomarker. The vision among the project consortium, comprising both research and industrial partners, is that the new biomarker will be predictive of a range of age-related conditions, which may be preventable through personalized nutrition. We combine philosophical analysis and ethnographic fieldwork to explore the possibilities and challenges of managing aging through bodily signs that are not straightforwardly linked to symptomatic disease. We document how the improvement of measurement brings about new conceptual challenges of demarcating healthy and unhealthy states. Moreover, we highlight that the reframing of aging as risk has social and ethical implications, as it is generative of normative notions of what constitutes successful aging and good citizenship.