“Taste” Versus “Science”


My recent discussion on the value of “originalism” has led to some interesting comments from respondents Mickey Mortimer and Mike Taylor. As I respect both of them, but disagree, I will post their comments in full below and respond to them in more detail rather than in comments. This gives me an excuse for yet another non-tooth-related post.First, Mickey Mortimer questions my argument in regards to Brachiosaurus brancai, as such rather than as Giraffatitan brancai.

The latter was proposed by Paul, then supported by Taylor, but I argued on the merits of the assignment for various reasons. Mickey asks about the null hypothesis, by which we presume all hypotheses must spring, either to refute or to support; specifically, a null hypothesis is any hypothesis which we seek to test. Mickey argues that the null hypothesis for systematic assumptions is that all taxa are dissimilar (NH1). Thus, when making arguments about taxonomy, we can separate taxa (and thus provide them names) when they differ. But there is a second hypothesis which we can test, one that is used and that contradicts the former, as long as it is applied in scale: all taxa are the same (NH2). Thus, if all taxa are different, we must find a scale of similarities instead of differences in compiling them into groups.

The problem here is that both are used in systematic work: We split species off, while joining them into families; but we also split families up, while joining families into other higher categories. In a non-Linnaean manner, we simply use new names, or abandon others as less useful (or completely useless); phylogenetic taxonomy presumes assumptions of synonymy among suprageneric taxa through the use of definitions, but otherwise lacks means of assessing division of taxa.

It is my understanding that both hypotheses are used, and for various purposes. NH2 is useful for combining taxa into supraspecific categories, but also for referring specimens to taxa. This assumption is what allows systematists to compile hypodigms from disparate elements, especially when there is little to no overlap among specimens. The systematist attempts to refute this hypothesis by trying to find features that compare well with other taxa, or by lacking similar taxa in the same region or horizon; in failing this, he affirms the specimens must belong to one another. Not that this is correct, but it is in his affirmation. He has failed to falsify this hypothesis.

But NH1 is also used, especially in the recognition of species (rather than the composition of the hypodigm). This is tested by the systematist attempting to refer a specimen to a known quantum, a hypodigm or species complex; failure results in the systematist trying to diagnose a new taxon. Thus I would reject the premise of just one useful null hypothesis. It may be that species systematics can use just one, but it is also arguable that using both is equally justifiable, or both justifiable in a single analysis for different scales.

Second, Mike Taylor makes the following argument:

I reject the notion that nomenclatural judgements should be dictated only by numerical phylogenetic analysis. However much we might wish we could find a purely objective basis for our nomenclature, the simple truth is that we can’t. All our decisions are informed by taste, experience and precedent, and pretending otherwise is fantasy.

This responds to a comment I made responding to Mickey, where I wrote:

Arguments previous standing were “taste” or “art” reasons, such as naming a new genus because the author thinks it is distinct enough, not justified through discriminate analysis.

Numerical phylogenetic analysis is not the only form of discriminate analysis, just one of the more prevalent forms. It does have a tendency of being used a lot, but I have argued that phylogenetic analysis is only a part of systematics, never its predicate. It is a tool, not the whole. Thus Mike is narrowing my use of “discriminate” to “numerical phylogenetic” with little justification. I recognize a lot of systematic analysis and valid taxa that have not be justified through phylogenetic analysis, and am certain that its use (such as Brontomerus mcintoshi) will continue.

But, there’s more.

When arguing about “taste,” why do we insist on a particular brand of “taste”? How do we quantify — or even qualify — “taste”? I argue we cannot.

Taxonomy is, in one way, a scientific, and rather logical practice: It facilitates communication. Communication in language, for which precision is an ideal, asks us to be able to use the same words for the same objects. And even though it evolves, language enforces terminology and structure. This includes the words for nouns and proper nouns. When labelling a specimen, we use a noun (the specimen number) coupled with a field id number which are unique to it. Intrinstically, this allows immediate understanding that no other object has this label, or complex of labels — this is accessional (or repository) nomenclature. The same is then true for taxonomic rather than accessional nomenclature, where a label implies a systematic rather than repositorial utility. In this case, each of these labels has a logical and scientific function. The most that “taste” gets thrown into this discussion is what label to use.

For accessioning fossils (or any specimen) a sequential value is used, and some institutions use different systems (the AMNH uses numeric succession when reposited, the RTMP uses a date, locality, and specimen when reposited in combination: AMNH FR 6517 [American Museum of Natural History, Fosill Reptiles Collection, reposited sequence 6517]; RTMP 79.20.1 [Royal Tyrell Museum of Palaeontology, collected in 1979, at site 20, first specimen]. This is logical, and the numbers of future accessioning can be predicted, and of the past inferred.

Not so taxonomy, if “taste” rules. No one can object to me making up new nomenclature, in a “taste” world, where sensibility is not qualifiable, where reason has no place.

“Taste” is useful when we want to name things, providing a context to a place, a person, or another taxon. It can be a joke, a pun, a logic puzzle, etc. (most of these up to date are catalogued at the Curiosities of Biological Nomenclature, and the list extends even to gene names). “Taste” is less useful when we want to assess anything, as “taste” becomes a blatant bias in big-s Science. It also leads to people “feeling” that taxa are “more different” than others, largely because of the perceived value of a character; the value of a character over another two or three chatacters; the location of the species in space or time; and even simply by the relative value of how much material is being used to support taxonomy. It can result in synonymy or rejection of synonymy, and often for the same reasons. And if the same argument can merely be inverted to argue for its opposite, we get a purely unscientific principle. That is “taste.”

“Taste” is art, and nomenclature is both; taxonomy and systematics is Science, and should not involve “taste” in any way. That is my argument. Because of this, without any value associated with the distinction between use of “Brachiosaurus brancai” and “Giraffatitan brancai,” I choose to use the form that appeared first. This involves the value of the “genus” (which is a category without scientific definition) with respect to a species (which has been [frequently] defined), and don’t think that those who erected or supported the use of Giraffatitan care, ignoring the qualification question while arguing against those that chose not to use this (optional) nomenclature.

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4 Responses to “Taste” Versus “Science”

  1. In a new record for being Devil’s Advocate, you’ve taken my argument and given me your argument. ;) You’ll note in my previous comment that I defended having species in separate genera as the null hypothesis, while you were the one saying synonymy is the null hypothesis.

    Here’s another attempt at explaining why I think you’re wrong with Giraffatitan. We have a ton of basal camarasauromorphs and almost all of them are monospecific genera- Abydosaurus mcintoshi, Cedarosaurus weiskopfae, Sonorasaurus thompsoni, etc.. But then we have Brachiosaurus altithorax, and _____ brancai. If we put brancai in Giraffatitan, no problem. It’s another basal camarasauromorph, could be closer to altithorax, could be closer to mcintoshi, we don’t know. But if we put brancai in Brachiosaurus, that’s more than just historical baggage, since we have another genus name available. Instead, it suggests relationship with altithorax to the exclusion of all other sauropod species. And this is misleading.

    Honestly, I think you just like being contrary with brancai more than anything else. I doubt you eschew using Lusotitan for instance, even though its case is identical to Giraffatitan (just more briefly argued). Or that you use the original Eustreptospondylus divesensis instead of Piveteausaurus because after all, it hasn’t been shown NOT to be sister to oxoniensis.

    • “Oops” on the flip-around. I will fix that; I think I had that reversed in the writing.

      I’ve never had the opportunity to assess the additional taxa you mention, but I would be prone to using the original nomenclature without analytical data demonstrating an alternate phylogenetic assignment. As I said. Try applying my argument to other taxa, and check where “unjustifiable taxonomy” might rear its head.

      1. I do not ascribe value to the “genus,” and as such it is viable as a clade name just like Brachiosauridae. In this case, Brachiosaurus is no different from Brachiosauridae. There should be no reason why each species should then suddenly, if “distinct enough” suddenly “deserves its own genus.” No, it doesn’t; it is in the eye of the ambitious taxonomist who decides he wants to coin the nomenclature. This is why I’ve taken to italicizing, PhyloCode-style, all taxonomy.

      2. I make the case beyond Giraffatitan to try to prove my point. This is not about Giraffatitan, it is just the most recent and (I think) most blatant example of the topic, as the author (no offense, Mike) offered no logical or scientific reason for justifying use of Paul’s “genus.”

      3. My argument does not prevent brancai from going into Giraffatitan, only that removal from its container Brachiosaurus requires justification beyond the “it’s different from altithorax.” This argument (the root of Mike’s, rather) is amply justified in the taxonomy I argue FOR: that altithorax and brancai are diagnostically and therefore systematically separate taxa. Brachiosaurus is merely the clade that contains them.

      Here’s a corollary: say we find a basal “dog,” Speothos-like or something, and begin questioning its relationship with other “dogs” (grounding our concept here by placing it at the root of extant Canidae), and decide that we want to support “separateness” by placing it into its own “family,” “Speothidae” or whatever. But phylogenetically, these taxa remain as they were before this new nomenclature and the taxonomy that results; no change means no difference, save nomenclature. Yet taxonomists argue that this added value increase their sense of variance.

      This is rank-based taxonomy, and it’s flawed.

      Mike is perpetuating rank-based taxonomy by pretending that the “genus” Giraffatitan is somehow equivalent to Brachiosaurus, rather than regarding this as tautological to brancai and althithorax in Brachiosaurus. The value is placed not on the species Mike described, but on the genus, as if it were somehow better than the species. Phylogenetically, this is meaningless drivel: Mike ignores the quest “what is a genus,” and pretends that either he doesn’t need to know, we don’t need to know, or that none of us have to care. Value-based taxonomy, or “taste,” is ART, not SCIENCE, and I am drawing that line here because of the perpetuation of this argumentation.

      I don’t have to pick on Mike for this. I can go to Paul: I can complain about the value of raising new “genera” as value-based taxonomy in iguanodonts, save that some of it is phylogenetically supported: some of the Wealden taxa being handled are of different grades and are showing up as such. But others, not so much. Before long, it will be the argument that the “trashcan” taxa Iguanodon and Megalosaurus were justifiably split up because we all knew the taxa didn’t belong there, regardless of any analysis proving such. Trash type species are the only other reason why I would support separating of referred species to old containers out; but in examples like Titanosaurus, which eventually looks to be more like Titanosaurinae or something, exclusion of australis and madagascariensis merely segregates indicus as crap — up to the point that indicus becomes diagnostic, which may be possible, and especially if it’s the same thing as Isisaurus colberti, a nomen whose only reason for existence is the degredation of Titanosaurus indicus as a “nomen dubium.”

      I am also aware that eventually, we can shift to a binomial species system, where Giraffatitan brancai is the appropriate name, because the full nomen is the species, not a genus-species couplet. But while this works for fossils, it is horrible practice for extant organisms, which show clearly the anagenetic model of speciation that is more likely to be prevalent among most, if not all complex organisms (especially all chordates, or even bilaterians). And the reason this is not a Devil’s Advocate argument is that this is SCIENCE versus TASTE; there really shouldn’t be another option than SCIENCE, and TASTE should only govern optional features such as the spelling of a nomen.

  2. Okay… after an online chat, you and I have managed to work through to the base difference in our positions. Which is, you don’t see genera as clades, merely as ranks. I think I stand in the vast majority of dinosaur paleontologists (and cladistic biologists in general) in that I see genera as clades within family clades. Not that genera are equivalent to each other, but they should be monophyletic.

    So yeah, if you want to use genera as non-phylogenetic labels that go along with species, I suppose it doesn’t matter if you call brancai Brachiosaurus or Giraffatitan. But if you follow basically every dinosaur paleontologist in assuming Brachiosaurus is a clade within Brachiosauridae, then B. brancai will only work with a small number of potential topologies assuming we keep the nomenclature of other brachiosaurids the same.

    • I actually described genera as ranks in the post to which we are replying. This is based largely on the form that in accordance with the rank-applying ICZN, many taxonomists (the grand majority, as you say) use “gen. et sp. nov.“. They regard species and genera as ranks, and they apply rules ICZN invents for them. Under phylogenetic nomenclature, only species are not ranks, and they are not clades, and they were defined (under a variety of definitions); other ranks and clades, however, lack definition that allow discriminating “genera” from them. Thus, I think even the value of “genus” is useless; applying even the minimum of scientific regard to the “genus” entity renders it useless, and yet its being sustained. I think this has a lot more to do with convention than that it has any semblance of scientific usage. And that’s the point.

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