‘Organism’ Versus ‘Biological Individual’: The Missing Demarcation

The demarcation of organisms from other biological individuals has received relatively little attention. In this paper, I extricate and systematize the different ways in which the organism–biological individual relationship has been construed: (1) coalescence of the two concepts, (2) biological individual eliminativism, (3) organism eliminativism, (4) organism as a ‘paradigmatic’ biological individual, (5) organism as a limit state towards which biological individuals tend in evolution and development, (6) organism as instantiating the whole in a part-whole hierarchy of biological individuals, (7) organism as equivalent to physiological individual, and (8) organism as a special kind of physiological individual. I show that, in most of these stances, the organism concept is too imprecise to be demarcated from other biological individuals, which fosters some form of eliminativism. I also argue that the comparisons between organisms and biological individuals are performed in two different modes: ‘horizontally’ (i.e., between individuals not related hierarchically) or ‘vertically’ (i.e., between individuals belonging to different levels within the same hierarchy). Finally, I explain the challenges that each of these comparison modes face and suggest that the ‘vertical’ mode adumbrates a potential way forward.