BIOLOGICAL INDIVIDUALITY: Integrating Scientific, Philosophical, and Historical Perspectives.
The field of biology is a very broad discipline. Etymologically, biology (bios + logos) means the study of life. But what is it that biology actually studies? Life itself is not a concrete, physical thing; rather, it is a function of living things. The focus of biology is not only the study of life as a function of certain things, but also the nature of living things that display the function of life. How does life as a function of certain things actually come about? Put another way, how do certain things come to display life activity or function? Central to these questions is that of biological individuality. What are biological individuals? What are the boundaries of and for biological individuals? These types of questions have been at the center of biological study, research, and thinking for several centuries.
In this edited volume, Lidgard and Nyhart provide a valuable service in pulling together various analyses of biological individuality. Three foci are distinguished in such an investigation: (1) the fundamental philosophical questions of biological individuality; (2) the historical analysis of how biologists have thought about individuality; and (3) how their reflections have influenced not only their research programs, but also how research programs, in turn, influenced philosophical perspectives on biological individuality and the nature of living things. Edited volumes sometimes suffer from a lack of coordination and a basic central theme, but the editors have dealt with that by providing an integrating introductory chapter, "Introduction: Working Together on Individuality," as well as an integrating philosophical analysis in a concluding chapter, "Philosophical Dimensions of Individuality," by Alan C. Love and Ingo Brigandt. The volume includes thirteen contributors spanning the spectrum of historians, philosophers, biologists, and sociologists.
The editors emphasize that although the concept of individuality is an important concept for biologists, there is no consensus on a definition of biological individuality. They even provide an extensive table (pp. 19-21) outlining the various definitional criteria for biological individuality as well as a graph (p. 23) indicating the year(s) of publications reflecting those definitional criteria and thereby providing a historical perspective.
There are a number of themes that arise in the consideration of biological individuality. One important theme is the evolutionary transitions in individuality (ETI). One such key ETI is that from unicellularity to multicellularity. The case study of the volvocine algae illustrates an attempt to understand this transition. This group of algae provides diverse examples of single-cell forms as well as colonial forms. In some forms, daughter colonies begin to form within the parent colony, raising the question of what constitutes an individual. Are the daughter colonies individuals only after they break from the colonies? In the transition from a unicellular form to a multicellular colonial form, what is the role of cell-to-cell communication and how many different forms of cell-to-cell connections and communications are there? Are such forms of communication fundamental features of the evolutionary transition from unicellularity to multicellularity? In some cases, the daughter colonies are actually clones of the parent colony so that we now have the introduction of levels of organization: one-celled organisms, colonies, and clones, potentially constituting three hierarchical levels. The matter of clones raises the intriguing question of whether all members of a clone, such as a cluster of beech trees sprouting from a single individual beech tree, actually constitute an individual. However, the concept of ETI might also be stretched in questionable ways as evidenced in the chapter by Andrew Reynolds, "Discovering the Ties That Bind: Cell-Cell Communication and the Development of Cell Sociology." Is the use of the term cell sociology a misapplication of the concept of sociology in order to provide some basis for the evolution of animal and human sociology?
The editors also introduce four problems, we might call them themes, related to the question of biological individuality: individuation, hierarchy, temporality, and constitution. Individuation concerns the identity and unity of a living thing. All living things display some form of metabolism and generally also some form of growth. Through all this change of material composition, what guarantees the identity of the individual so that its identity and unity as an individual is retained? Another illustration of individuation is in speciation and the concept of species as individuals. At what point is a species as individual distinct from another species?
Hierarchy is another important theme that reflects the nature of the levels of organization of living things. During the nineteenth century, there was a very active debate between two basic schools of thought: vitalism and reductionism. Vitalism emphasized a holistic view of living things whereby the whole individual is greater than the sum of its parts. Reductionism emphasized the view that the individual can be understood by examining the mechanistic functioning of the constituent parts. This debate was continued in the twentieth century by organicism and systems thinking in biology, which emphasized a holistic view replacing the earlier vitalist views. Central to this discussion is the question of how the entities of one level are related to the entities of a higher level. Are the entities at each level to be considered as integral wholes or are the entities merely part of a higher level? Expressed another way, are we dealing with part-whole relationships or with whole-whole relationships as in enkaptic hierarchies? Olivier Rieppel in his chapter, "Biological Individuality and Enkapsis: From Martin Heidenhain's Synthesiology to the Volkisch National Community," lays out how the theory of enkapsis was used by some to argue for individuals to sacrifice themselves for the good of the whole national community in Nazism. Ingo Brigandt, in the chapter "Bodily Parts in the Structure-Function Dialectic," makes a case for considering functions or activities as entities that were proposed to become integrated into the levels of hierarchies. However, doing so would bring into question whether functions can really be independent of entities and whether this would obscure the fundamental meaning of hierarchical levels of structure.
Temporality is another theme that addresses the evolution or emergence of biological individuality. How do individuals at one stage of evolution relate to subsequent stages of evolution? A further issue concerns the units of selection and whether species are individuals, and thus, are possibly considered to be subject to selection. Temporality also relates to developmental stages and how stages relate to the identity of a biological individual. One very intriguing and significant historical discussion concerns the alternation of generations. For living things that display a remarkably distinct alternation of generations such as between haploid and diploid generations, to what extent are we dealing with distinct biological individualities? Are the alternate generations a single biological individual or are they separate biological individuals?
A fourth theme is that of constitution: what constitutes a biological individual? This is also related to the questions of part-part, part-whole, and whole-whole relations that are important considerations of hierarchical levels of structure. Additional fascinating aspects to this theme include parasitism and symbiotic relations. Parasitism involves intimate relations between host and parasite such that the parasite typically exists within the boundary of the host organism. In such a relationship, what constitutes the individual? Are they to be seen as a single individual or as two distinct individuals that are at least for a time intimately connected to each other? This is perhaps even more complex with regard to symbiotic relationships, especially with regard to obligatory symbiotic relationships. One clear example is the case of intestinal bacteria in human digestive systems. It is reported that 30% of our blood metabolites are bacterial products. Without such beneficial intestinal bacteria, human survival is at stake. The bacteria are considered to be biological individuals in their own right. So how does that affect human individuality? Another example is lichens, which are obligatory symbionts of specific fungi integrated with a specific form of algae. We intuitively recognize lichens as biological individuals. Is this perhaps an example of a whole-whole relationship?
This introduces a new concept of biological individuality, that of holobionts. Holobionts are biological individuals that encapsulate autonomous or semi-autonomous individuals into a functioning organism, as illustrated in the examples of symbiosis given above. Perhaps the process of endosymbiosis in which prokaryotes became incorporated into other eukaryotic cells is an early form of holobionts. Holobionts may also have impacts on genetic activity (viral insertions into a host's genetic makeup) and immunological recognition of self and nonself.
In short, this book on biological individuality is relevant to biological research and helps one develop a richer philosophical understanding of the nature of living things. It may also assist in reminding readers of the limits of reductionist and mechanistic understandings of the nature of life as a function of living things. Reductionist and mechanistic views are heavily dependent on a philosophical materialism, which is opposed to a deeper Christian, theistic view of reality.
Reviewed by Uko Zylstra, Professor of Biology Emeritus, Calvin College, Grand Rapids, MI 49546.
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|Title Annotation:||SCIENCE AND RELIGION|
|Publication:||Perspectives on Science and Christian Faith|
|Article Type:||Book review|
|Date:||Mar 1, 2019|
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