Why Do We Bother?

`I don't REJOICE in insects at all,' Alice explained, `because I'm rather afraid of them -- at least the large kinds. But I can tell you the names of some of them."
`Of course they answer to their names?' the Gnat remarked carelessly.
`I never knew them do it.'
`What's the use of their having names,' the Gnat said, `if they won't answer to them?'
`No use to THEM,' said Alice; `but it's useful to the people who name them, I suppose. If not, why do things have names at all?'--Lewis Carroll, Alice Through the Looking Glass

I recently came across a comment reported on The Voltage Gate questioning why we bother distinguishing insects and arachnids. Jeremy Bruno has commented on it himself there, but I'm going to put my own oar in. I'm taking the liberty of repeating the main body of the original comment:

Why spiders SHOULD be considered "insects". Or at least a sub-category of insects. Exo-skeleton. Multiple legs. Creepy crawly. And if it quacks like a duck, people. So for some stuffy scientists, biologists, zoologists, paleantolgists, etc, to come up with artificial nit-picky labelings and distinctions, to make spiders a totally different species, like "arachnids", is silly. Why can't "aranchids" simply be considered a TYPE of "insect"??? (As well as scorpions, or dust mites, or whatever else.) The average person (and even insect and animal lover) doesn't generally in practical purposes separate spiders from the category of "bugs" or "insects". Why?? Cuz even though there ARE SOME basic differences here and there (like 8 legs instead of 6, two body segments instead of three, and claw jaw munching distinctions, whatever blah blah, those are just hair-splitting differences in the overall picture of it. Cuz again, just who came up with these uptight definitions of these things in the first place. When you see a spider in your bathtub (and I like spiders, by the way), you automatically think "bug" or "insect" or "creepy crawly" not "aracnid". So let's lose the silliness already on this subject.

Now, if I was really being nit-picky, I would reply that arachnids are not a separate 'species' from insects, but many thousands of species; that scorpions and dust-mites are arachnids; the presence above of at least three different spellings of arachnid; but all that would be merely pettiness and not replying to the main meat of the argument, wouldn't it?

And if it quacks like a duck, people.

It does not. Alright, I may be slightly biased by the fact that I work on arachnids, but I find the distinctions between arachnids and insects far more significant than the differences between most vertebrates (which is not surprising because they've probably been distinct for longer). Which brings me onto my next point:

...even though there ARE SOME basic differences here and there (like 8 legs instead of 6, two body segments instead of three, and claw jaw munching distinctions, whatever blah blah, those are just hair-splitting differences in the overall picture of it.

These differences are hair-splitting? Good thing I didn't have a mouthful of soft-drink when I read that, because the dry-cleaning bill would have been drastic. Arachnids are only insects, and the differences between them are minor. Dogs are only newts, and the differences are even less significant. After all, dogs and newts have the same number of legs, the same basic body arrangement, and even process their food in much the same way, so why do we bother to distinguish them?

So for some stuffy scientists, biologists, zoologists, paleantolgists [sic], etc, to come up with artificial nit-picky labelings and distinctions, to make spiders a totally different species, like "arachnids", is silly.

I've already pointed out that the differences are not artificial. As for the labels - all labels are artificial. Distinct categories of things exist all around us, and it is ourselves who decide whether a given category receives a name and what that name is. The importance of a name does not lie in the name itself, but in the concepts it communicates. Communication is the key here. In the general human mode of perception, something doesn't really exist until it's been given a name.

Why can't "aranchids" [sic] simply be considered a TYPE of "insect"???

Dude, what's with the capitals and multiple exclamation points? Anyway, as follows on from the previous point, there is not inherent reason why insects can't be arachnids, because the names for categories are ultimately arbitrary. And yet the simple fact is that people have come to an agreement that the name 'insect' shall be used for a category that excludes arachnids, meaning that whenever I hear someone referring to an 'insect' I automatically feel confident that what they are talking about has six legs, three tagmata (not segments - the insect body actually has many more than three segments) instead of two, mandibles rather than chelicerae, two compound eyes, and a whole host of other features. If I wanted to refer to animals with a chitinous exoskeleton, jointed legs, and any other feature shared by arachnids and insects, I could just say 'arthropods', because that's what convention has decided that group should be called.

Every discipline has its own set of terminology that becomes automatic over time. If I was considering mechanics, I might decide that there was no point in distinguishing spanners and screwdrivers - both are made of metal, both are used to tighten/loosen things, both hurt if you drop them on your toe. So long as I didn't need to talk to anyone else about spanners and screwdrivers, it wouldn't matter a damn what I called them in my own head. But if I needed to ask someone to fetch me one, it might be best for me to defer to convention.

When you see a spider in your bathtub (and I like spiders, by the way), you automatically think "bug" or "insect" or "creepy crawly" not "aracnid".

I don't. I might if I didn't know what an arachnid or an insect was, but that doesn't mean that I'm correct, only that I don't know the difference. To use another analogy, I personally know nothing about cars, and couldn't tell one car from another to save myself (someone asked me recently what kind of car my boyfriend owns, and I replied "a red one"). This does not mean that there is no difference between a Honda Accord or Holden Kingswood or Aston Martin or whatever, only that I personally don't know to recognise them.

As I said, communication is the key. Ultimately our names for the things around us are dictated by nothing more than convention, but we try to agree on what they mean because that's how we know that the heck we're all talking about.