During the last decades the question of defining life has gained increased interest but, at the same time, the difficulty in reaching consensus on a possible answer has led many to sceptical positions. This, in turn, has raised a wider debate about why defining life is so hard and controversial. Such a debate introduces additional aspects to be considered, from a general ‘philosophy-of-science’ standpoint, like the role and nature of a definition of life within biology itself. In this talk, I will focus on those (‘meta-scientific’) aspects, arguing that progress can be made (and has, indeed, been made) if we conceive definitions of life as open heuristic tools that contribute(d) to develop specific research strategies in the biological sciences and, more generally, to increase our understanding of life’s complexity. In contrast with pragmatic or operationalist approaches, I will defend that definitions of life comprise a set of ontological assumptions/claims, together with an inherent unifying vocation, so they should be subject to comparison and critical assessment, closely related to the success or failure of the corresponding research programs, but also to the success or failure in establishing well-grounded interconnections among the latter. The search for a more coherent, integrated and generalized theory of biology cannot be pursued without keeping an empirical standpoint, and the exercise of defining life should not be taken as an obstacle but as a valuable (and, of course, evaluable) instrument to achieve that goal.
Kepa Ruiz-Mirazo is a physicist who has devoted most of his research career to study the epistemological foundations of biology, focusing on the problem of origins of life and its non-trivial chemical roots. After completing a PhD in Sciences (Complex Systems) at the UPV/EHU, he worked as a postdoc at the Centre for Astrobiology (Spain), Institute for Polymers at ETH-Zürich (Switzerland) and D. Biology of the University Roma Tre (Italy). His main scientific contributions have been in the elaboration of protocell models, both in vitro and in silico. This has reinforced a theoretical perspective according to which phase heterogeneity, molecular diversity and the functional coupling among various kinds of physical and chemical processes are key to understand the emergence and nature of biological phenomena. Currently on sabbatical at the University of Calgary, he is full-time research staff of the University of the Basque Country (UPV/EHU), where he has a double affiliation: at the D. Philosophy, as a senior researcher of the IAS-Research Group (http://www.ias-research.net/), and also at the Biofisika Institute (Basque Excellence Research Centre), where he leads the Theoretical/Protocell Biophysics Lab (https://www.biofisika.org/en/research/theoretical-protocell-biophysics-laboratory).