Category Mistakes in Scientific Metaphysics

Buckle up...

Introduction

Before I do move onto the Species-As-Explanations/Hypotheses view, I’d like to mention some metaphysical issues. Now, given the ways in which scientists discuss the metaphysics of their disciplines, I think there are some category mistakes being made here too. In general or universal sciences like physics, it may be a little clearer what is meant by “quantum fields exist” or “there is a waveform” (neither of which I am qualified to discuss), but in the so-called “special sciences”, including biology, things (and I mean that literally) get very complex and messy very quickly.

One area that is particularly messy is the notion that living things come in an inclusive hierarchy. Usually this is given as:

Gene

Cell

Organ

Organism

Superorganism (colonial organisms)

Population/Deme

Metapopulation

Species

… [whatever the biologist wants to add as higher groups, ranks, or levels]

Some think this hierarchy has to be universal to all life, while others think that the reality stops at organism or superorganism. Some believe the entire Linnaean hierarchy is real, while some hold that Phyla and/or Kingdoms are real, and so on, using the term “real” to mean something like “natural” or “mind-independent”. This goes back a ways: Buffon in the late eighteenth century was one of those who thought only organisms are real (Sloan 1985). Others argued strongly that species were real but genera and up weren’t.

Hierarchism (my term) is quite common among biologists and paleontologists who do taxonomy, but also among “systems thinkers”. And the relationships between the levels are very often conceived as part-whole relations (mereology). In the systems version, the levels are representations of particular organisational or functional attributes, such as the “major transitions of evolution” tradition.

However, as Darwin once wrote, “It is absurd to talk of one animal being higher than another.— We consider those, when the intellectual faculties [/] cerebral structure most developed, as highest.— A bee doubtless would when the instincts were —”,^[1] the choice of criterion is itself somewhat species-specific. In taxonomy/systematics, hierarchism is associated with there being natural and general ranks as in the Linnaean scheme, and for that reason I think of it, in that context, as rankism or “rank realism”. As will become clear, I do not think any ranks are natural.