Both concepts of the holobiont and the immune system are at the heart of an ongoing scientific and philosophical examination concerning questions of the organism’s individuality and identity as well as the relations between organisms and their environment. Examining the holobiont, the question of boundaries and individuality is challenging because it is both an assemblage of organisms with physiological cohesive aspects. I discuss the concept of immunity and the immune system function from the holobiont perspective. Because of the host-microbial close (...) relations of codependence and interdependence, the holobiont is more often than not confused with the host, as the host is the domain in which this entity exists. I discuss the holobiont unique ecological characteristics of microbial assemblages connected to a host in a network of interactions in which the host is one of the organisms in the community but also its landscape. Therefore, I suggest viewing the holobiont as a host-ecosystem and discuss the implication of such a view on the concept of immunity and the meaning of protection. Furthermore, I show that viewing the holobiont as a host ecosystem opens the possibility of using the same ecological definition of boundaries and immunity dealing with an ecological system. Thus, the holobiont’s boundaries and immunity are defined by the persistence of its complex system of interactions integrating existing and new interactions. This way of thinking presents a notion of immunity that materializes as the result of the complex interdependence relations between the different organisms composing the holobiont similar to that of an ecosystem. Taking this view further, I discuss the notion of immunogenicity that is ontologically heterogeneous with various causal explanations of the processes of tolerance and targeted immune response. Finally, I discuss the possible conceptualization of already existing and new biomedical practices. (shrink)

This article offers an analysis of ecologist Charles Elton’s “functional” concept of the niche and of the notion of function implicitly associated with it. It does so in part by situating Elton’s niche concept within the broader context of the “functionalist-interactionist” approach to ecology he introduced, and in relation to his views on the relationship between ecology and evolution. This involves criticizing the common claim that Elton’s idea of species as fulfilling functional roles within ecological communities committed him to an (...) idea of communities as units of selection. While such a claim implicitly attributes to Elton an understanding of function along the lines of the selected-effects theory of function advocated by many biologists and philosophers of biology, Elton’s use of the niche concept, I maintain, involves an understanding of function more along the lines of alternative nonselectionist theories such as the causal-role, goal-contribution, and organizational theories. I also briefly discuss how ecologists after Elton also tend to have typically adopted a nonselectionist understanding of the function concept, similar to his. (shrink)

This paper discusses Millstein’s criticism of the consensus view formed against selected-effects ecological functions. I argue that Millstein’s defense of coevolution-based selected-effects ecological functions applies to a notion of function as an activity, whereas proponents of the consensus view are concerned with a notion of ecological function as the contribution of an organism, population, species, or abiotic item to the maintenance of its community and/or the functioning of its ecosystem. Millstein’s arguments hence do not invalidate the consensus view but draw (...) attention to a notion of function that has been neglected in philosophical discussions and that deserves more attention. (shrink)