Arguing about species: Is it evidence, or ego? | Hacker News Reader

Arguing about species: Is it evidence, or ego?

johnhawks.net

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To argue about species is to argue about definitions and to argue about definitions is to create paradoxes.

For example: A and B (and C) are the same species when they can produce offspring creates these questions:

- What if A and B produce infertile offspring

- What is A and B can reproduce, B and C can reproduce by A and C can not?

We humans and our need to put lines on continuous stuff, we keep ourselves busy with such futile things.

Just because an abstraction isn't perfect or it can be misused doesn't mean that it can't also be vitally useful in many circumstances.

Exactly. But endlessly bitching about the precise border is a waste of time, because all of our abstractions (including words in every language) break if you zoom in too close on them. People need to learn to live with soft, fuzzy boundaries on concepts.

Just recently I was pondering exactly what kind of information classification schemes give you. I ran around in Gödelian circles until I gave up.

Especially for prokaryotes, how to define what is a species is an active problem in the philosophy of biology. IIRC, Laura Franklin-Hall at NYU has written about this (https://as.nyu.edu/faculty/laura-rebecca-franklin.html). In a research setting this is far from a trivial question. One lab's E.coli may show different characteristics than another lab's, even if they are the same strain.

Philosophers have been pondering on the definition of 'human' (and other categorizations) for at least 2000 years.

The relation with this problem is that you can offer the following attempt at definition: "it's human if the direct ancestors are human". Of course, it fails ;)

Another attempt is via attributes (fe, "if it has a head, arms, legs, and an IQ of at least X and DNA that has ..., it's human"). This also quickly fails.

I think the current consensus amongst philosophers is that a binary categorization is impossible in these cases. ie, whatever the definition, you will either exclude things you want to be included and/or include things you don't want in there.

What are the current edge cases for 'human' and 'non-human' which makes the line so blurred that our common sense is no longer sufficient to judge, and we need to invoke philosophy, and further philosophy without input from biology?

There are a set of questions about when human life starts. Is it when the sperm touches the egg? When the zygote forms?

There is no firm answer, and the choice depends on one's philosophy. The US Supreme Court - and in this case I am suggesting that the courts are a sort of applied philosophy - took input from biology in deciding Roe v. Wade.

Medical ethics, again a form of philosophy, says that human embryo experimentation must not continue past two weeks, based on input from biology. That's when the central nervous system starts to form, and marks the end of when the embryo can split into twins. It was also not believed possible to keep an embryo alive outside the womb that long, but now it's possible. http://www.npr.org/sections/health-shots/2017/03/02/51628089...

If the definition of human is related to DNA, then is cancer human? What about immortal cell lines? Parasitic cancers like Canine transmissible venereal tumor?

Were Neanderthals human? Denisovans?

I just checked wikipedia on https://en.wikipedia.org/wiki/Species_problem

so which of the 26 taxonomy models are you referring to ?

Clearly, it's an utter mess.

The selection pressure will be towards more and more species since it has more clickbait potential: "New human ancestor species discovered in Africa", "Ecologists discover 10,000 new bacterial species in a hydrothermal vent", etc.

I really don't see any pressures currently in favor of "lumping". I guess just inertia.

I ... don't think you have much experience with the issue?

"Until the late 1980s, as many as 32 subspecies were recorded; genetic study of mitochondrial DNA[35] found many of these are too similar to be recognized as distinct at a molecular level. Following the research, the canonical Mammal Species of the World (3rd ed.) recognizes six subspecies, five of which are solely found in Latin America" - https://en.wikipedia.org/wiki/Cougar#Subspecies

There is a continuous question of if a given "species" is really a distinct species, and thus protected under the Endangered Species Act, or if it's a subspecies or hybrid. There is political pressure to lump, because of the cost of protecting a species. Some examples of lumping:

"Extensive studies conducted by researchers at the Denver Museum of Nature and History have shown that the Preble meadow jumping mouse is not a distinct species from other common mice and does not deserve protection under the Endangered Species Act." - http://www.citizenreviewonline.org/jan2004/rodents.htm

Is the grey wolf really a distinct species? https://phys.org/news/2016-07-gray-wolf-endangered-species-g... .

"The Fish and Wildlife Service (Service) under the authority of the Endangered Species Act of 1973 (Act), as amended, proposes to remove the plant Echinocereus lloydii (Lloyd's hedgehog cactus) from the Federal List of Endangered and Threatened Plants. Lloyd's hedgehog cactus was listed as endangered on October 26, 1979, due to threats of collection and highway projects. Recent evidence indicates that Lloyd's hedgehog cactus is not a distinct species but rather a hybrid. Therefore, Lloyd's hedgehog cactus does not qualify for protection under the Act." - https://www.gpo.gov/fdsys/pkg/FR-1996-06-14/html/96-15124.ht...

Interesting, thanks.

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