This paper examines David Hull’s and Peter Godfrey-Smith’s accounts of biological individuality using the case of biofilms. Biofilms fail standard criteria for individuality, such as having reproductive bottlenecks and forming parent-offspring lineages. Nevertheless, biofilms are good candidates for individuals. The nature of biofilms shows that Godfrey-Smith’s account of individuality, with its reliance on reproduction, is too restrictive. Hull’s interactor notion of individuality better captures biofilms, and we argue that it offers a better account of biological individuality. However, Hull’s notion of (...) interactor needs more precision. We suggest some ways to make Hull’s notion of interactor and his account of individuality more precise. Generally, we maintain that biofilms are a good test case for theories of individuality, and a careful examination of biofilms furthers our understanding of biological individuality. (shrink)

Attempts to explain the origin of macroevolutionary innovations have been only partially successful. Here it is proposed that the patterns of major evolutionary transitions have to be understood first, before it is possible to further analyse the forces behind the process. The hypothesis is that major evolutionary innovations are characterized by an increase in organismal autonomy, in the sense of emancipation from the environment. After a brief overview of the literature on this subject, increasing autonomy is defined as the evolutionary (...) shift in the individual system–environment relationship, such that the direct influences of the environment are gradually reduced and a stabilization of self-referential, intrinsic functions within the system is generated. This is described as relative autonomy because numerous interconnections with the environment and dependencies upon it are retained. Features of increasing autonomy are spatial separations, an increase in homeostatic functions and in body size, internalizations and an increase in physiological and behavioral flexibility. It is described how these features are present in different combinations in the major evolutionary transitions of metazoans and, consequently, how they should be taken into consideration when evolutionary innovations are studied. The hypothesis contributes to a reconsideration of the relationship between organisms and their environment. (shrink)

The book presents a new way of understanding Darwinism and evolution by natural selection, combining work in biology, philosophy, and other fields.

The role of interaction in learning is essential and profound: it must provide the means to solve open problems (those only vaguely specified in advance), but cannot be captured using our familiar formal cognitive tools. This presents an impasse to those confined to present formalisms; but interaction is fundamentally dynamical, not formal, and with its importance thus underlined it invites the development of a distinctively interactivist account of life and mind. This account is provided, from its roots in the interactivist (...) biological constitution of life, through the evolution of the dual internal regulatory capacities expressed as intentionality and intelligence, to its expression in self-directed anticipative learning in persons and in science. (shrink)

Biology lacks a central organism concept that unambiguously marks the distinction between organism and non-organism because the most important questions about organisms do not depend on this concept. I argue that the two main ways to discover useful biological generalizations about multicellular organization--the study of homology within multicellular lineages and of convergent evolution across lineages in which multicellularity has been independently established--do not require what would have to be a stipulative sharpening of an organism concept.

In this paper we review and argue for the relevance of the concept of open-ended evolution in biological theory. Defining it as a process in which a set of chemical systems bring about an unlimited variety of equivalent systems that are not subject to any pre-determined upper bound of organizational complexity, we explain why only a special type of self-constructing, autonomous systems can actually implement it. We further argue that this capacity derives from the ‘dynamic decoupling’ (in its minimal or (...) most basic sense: the phenotype–genotype decoupling) by means of which a radically new way of material organization (minimal living organization) is achieved, allowing for the long-term sustenance of systems whose individual-metabolic and collective-historical pathways become thereafter deeply intertwined. (shrink)

What makes a biological entity an individual? Jack Wilson shows that past philosophers have failed to explicate the conditions an entity must satisfy to be a living individual. He explores the reason for this failure and explains why we should limit ourselves to examples involving real organisms rather than thought experiments. This book explores and resolves paradoxes that arise when one applies past notions of individuality to biological examples beyond the conventional range and presents an analysis of identity and persistence. (...) The book's main purpose is to bring together two lines of research, theoretical biology and metaphysics, which have dealt with the same subject in isolation from one another. Wilson explains an alternative theory about biological individuality which solves problems which cannot be addressed by either field alone. He presents a more fine-grained vocabulary of individuation based on diverse kinds of living things, allowing him to clarify previously muddled disputes about individuality in biology. (shrink)

Concentrating on problems that commonly perplex general readers and beginning students, John Maynard Smith discusses fundamental issues in biology, with emphasis on evolution, development, and cognition. He provides a nontechnical account of molecular genetics, which is the foundation of modern biology, and explores such issues as heredity, animal behavior, the definition and origin of life, the brain and how we know things, artificial and natural intelligence, and genetics. The book is unique in presenting modern ideas in terms that can be (...) understood without an in-depth knowledge of biology. (shrink)

Biology lacks a central organism concept that unambiguously marks the distinction between organism and non-organism because the most important questions about organisms do not depend on this concept. I argue that the two main ways to discover useful biological generalizations about multicellular organization—the study of homology within multicellular lineages and of convergent evolution across lineages in which multicellularity has been independently established—do not require what would have to be a stipulative sharpening of an organism concept.

Our aim in the present paper is to approach the nature of life from the perspective of autonomy, showing that this perspective can be helpful for overcoming the traditional Cartesian gap between the physical and cognitive domains. We first argue that, although the phenomenon of life manifests itself as highly complex and multidimensional, requiring various levels of description, individual organisms constitute the core of this multifarious phenomenology. Thereafter, our discussion focuses on the nature of the organization of individual living entities, (...) proposing autonomy as the main concept to grasp it. In the second part of the article we show how autonomy is also fundamental to explaining major evolutionary transitions, in an attempt to rethink evolution from the point of view of the organizational structure of the entities/organisms involved. This gives further support to the idea of autonomy not only as a key to understanding life in general but also the complex expressions of it that we observe on our planet. Finally, we suggest a possible general principle that underlies those evolutionary transitions, which allow for the open-ended redefinition of autonomous systems: namely, the relative dynamic decoupling that must be articulated among distinct parts, modules or modes of operation in these systems. (shrink)

Darwin’s classic ‘Origin of Species’ (Darwin 1859) described forces of selection acting upon individuals, but there remains a great deal of controversy about what exactly the status and definition of a biological individual is. Recently some authors have argued that the individual is dispensable – that an inability to pin it down is not problematic because little rests on it anyway. The aim of this paper is to show that there is a real problem of biological individuality, and an urgent (...) need to arbitrate over the current plethora of solutions to it. (shrink)

According to the traditional nomological-deductive methodology of physics and chemistry [Hempel and Oppenheim, 1948], explaining a phenomenon means subsuming it under a law. Logic becomes then the glue of explanation and laws the primary explainers. Thus, the scientific study of a system would consist in the development of a logically sound model of it, once the relevant observables (state variables) are identified and the general laws governing their change (expressed as differential equations, state transition rules, maximization/minimization principles,. . . ) (...) are well determined, together with the initial or boundary conditions for each particular case. Often this also involves making a set of assumptions about the elementary components of the system (e.g., their structural and dynamic properties) and modes of local interaction. In this framework, predictability becomes the main goal and that is why research is carried out through the construction of accurate mathematical models. Thus, physics and chemistry have made most progress so far by focusing on systems that, either due to their intrinsic properties or to the conditions in which they are investigated, allow for very strong simplifying assumptions, under which, nevertheless, those highly idealized models of reality are deemed to be in good correspondence with reality itself. Despite the enormous success that this methodology has had, the study of living and cognitive phenomena had to follow a very different road, because these phenomena are produced by systems whose underlying material structure and organization do not permit such crude approximations. Seen from the perspective of physics or chemistry, biological and cognitive systems are made of an enormous number of parts or elements interacting in non-linear and selective ways, which makes very difficult their tractability through mathematical models. In addition, many of those interacting elements are hierarchically organized, in a way that the “macroscopic” (observable) parts behave according to rules that cannot be, in practice, derived from simple principles at the level of their “microscopic” dynamics.. (shrink)

The fitness of any evolutionary unit can be understood in terms of its two basic components: fecundity (reproduction) and viability (survival). Trade-offs between these fitness components drive the evolution of life-history traits in extant multicellular organisms. We argue that these trade-offs gain special significance during the transition from unicellular to multicellular life. In particular, the evolution of germ–soma specialization and the emergence of individuality at the cell group (or organism) level are also consequences of trade-offs between the two basic fitness (...) components, or so we argue using a multilevel selection approach. During the origin of multicellularity, we study how the group trade-offs between viability and fecundity are initially determined by the cell level trade-offs, but as the transition proceeds, the fitness trade-offs at the group level depart from those at the cell level. We predict that these trade-offs begin with concave curvature in single-celled organisms but become increasingly convex as group size increases in multicellular organisms. We argue that the increasingly convex curvature of the trade-off function is driven by the cost of reproduction which increases as group size increases. We consider aspects of the biology of the volvocine green algae – which contain both unicellular and multicellular members – to illustrate the principles and conclusions discussed. (shrink)

We address three fundamental questions: What does it mean for an entity to be living? What is the role of inter-organismic collaboration in evolution? What is a biological individual? Our central argument is that life arises when lineage-forming entities collaborate in metabolism. By conceiving of metabolism as a collaborative process performed by functional wholes, which are associations of a variety of lineage-forming entities, we avoid the standard tension between reproduction and metabolism in discussions of life – a tension particularly evident (...) in discussions of whether viruses are alive. Our perspective assumes no sharp distinction between life and non-life, and does not equate life exclusively with cellular or organismal status. We reach this conclusion through an analysis of the capabilities of a spectrum of biological entities, in which we include the pivotal case of viruses as well as prions, plasmids, organelles, intracellular and extracellular symbionts, unicellular and multicellular life-forms. The usual criterion for classifying many of the entities of our continuum as non-living is autonomy. This emphasis on autonomy is problematic, however, because even paradigmatic biological individuals, such as large animals, are dependent on symbiotic associations with many other organisms. These composite individuals constitute the metabolic wholes on which selection acts. Finally, our account treats cooperation and competition not as polar opposites but as points on a continuum of collaboration. We suggest that competitive relations are a transitional state, with multi-lineage metabolic wholes eventually outcompeting selfish competitors, and that this process sometimes leads to the emergence of new types or levels of wholes. Our view of life as a continuum of variably structured collaborative systems leaves open the possibility that a variety of forms of organized matter – from chemical systems to ecosystems – might be usefully understood as living entities. (shrink)

Since Darwin it is widely accepted that natural selection (NS) is the most important mechanism to explain how biological organisms—in their amazing variety—evolve and, therefore, also how the complexity of certain natural systems can increase over time, creating ever new functions or functional structures/relationships. Nevertheless, the way in which NS is conceived within Darwinian Theory already requires an open, wide enough, functional domain where selective forces may act. And, as the present paper will try to show, this becomes even more (...) evident if one looks into the problem of origins. If there was a time when NS was not operating (as it is quite reasonable to assume), where did that initial functional diversity, necessary to trigger off the process, come from? Self-organization processes may be part of the answer, as many authors have claimed in recent years, but surely not the complete one. We will argue here that a special type of self-maintaining organization, arising from the interplay among a set of different endogenously produced constraints (pre-enzymatic catalysts and primitive compartments included), is required for the appearance of functional diversity in the first place. Starting from that point, NS can progressively lead to new (and, at times, also more complex) organizations that, in turn, provide wider functional variety to be selected for, enlarging in this way the range of action and consequences of the mechanism of NS, in a kind of mutually enhancing effect. (shrink)