A refreshed approach to homology—Prioritizing epistemology over metaphysics

Abstract

Unease with the inclusion of “sameness” in Owen's definition of homology characterizes a substantial part of the literature on this subject, where this term has acquired an increasingly strict metaphysical flavor. Taken for granted the existence of body features that are “the same,” their existence has been explained by appealing to universal laws of form, as the product of common ancestry, or in terms of proximal causes responsible for the emergence of conserved developmental modules. However, a fundamentally different approach is possible, if we shift attention from metaphysics to epistemology. We may reword Owen's statement as follows: organs of different animals, in so far as they can be described as the same despite any difference in form and function, are called homologues. The proposed framework provides an umbrella for both the traditional, all‐or‐nothing concept of homology, and the less fashionable alternatives of factorial or partial homology, as well as for an extension of homology from form to function. No less attractive is the prospect to handle also ghost homologues, the body parts or organs of which there is non‐objective evidence in a given clade, but can nevertheless be represented, in a description that encapsulates some of the traits observable in their extant homologue in the sister clade. Stripped of its different and constraining metaphysical explanations, homology survives as an anchor concept to which different nomadic disciplines and research agendas can be associated.

Against unifying homology concepts: Redirecting the debate

“…The identification of distinct biological parts as in some sense the same is fundamental to the practice of comparative anatomy (Wake, 1994). More than 150 years after the term homology stabilized as a name for this underlying relationship, debate continues as to how precisely it should be conceptualized (Bock & Cardew, 1999; Cracraft, 2023; Hall, 1994; Minelli, 2023). This debate has sparked an equally lively conversation about how to respond to the wide range of conceptualizations on offer.…”

Fundamentals of Plant Morphology and Plant Evo-Devo (Evolutionary Developmental Morphology)

“…One reason why continuum morphology has not been widely accepted in botany is because of the emphasis that has been given to the position criterion in establishing homology. Even when structures such as leaves or roots had multiple evolutionary origins [ 28 ] and thus are defined within a specific clade such as in taxic homology [ 29 ], position still plays an important role [ 8 , 30 , 31 ]. Hence, it is often thought that—in most vascular plants—the position of an organ determines its homology [ 8 ].…”

“…Minelli [ 1 ] referred to factorial and combinatorial homology. Rutishauser and Moline [ 44 ] and Minelli [ 31 ] discussed yet other homology concepts that have been proposed by various authors.…”

Can you tell me anything about homology? Any one thing that is new?

“…In his article “A refreshed approach to homology—prioritizing epistemology over metaphysics,” Alessandro Minelli approaches the “homology‐problem” in a more fundamental way (Minelli, 2023). Giving a stringent and elegant (though not exhaustive nor exhausting) overview of the historical development of the conception of homology, Minelli proposes to shift from metaphysics to epistemology.…”

“…In his article "A refreshed approach to homology-prioritizing epistemology over metaphysics," Alessandro Minelli approaches the "homology-problem" in a more fundamental way (Minelli, 2023).…”