I don’t assert that scientists should never use everyday terms in special senses as a general principle. I understand why scientists sometimes use words that originated in everyday contexts, but in special senses that are sometimes counterintuitive. For example, Asimov (I think it was him, but it doesn’t matter for my point) said something like this: to a lay person, spending five hours trying to pound a nail into a wall, and hardly making any progress, to the point where the person is sweating and exhausted, might be called “hard work”, whereas, the way physicists use the term “work”, almost no work has been done at all. And the physicists’ definition of “work” is very useful, not just in purely theoretical contexts but even in a number of practical contexts. So sure, in physics class you learn to use the word “work” in a more precise sense, and that’s a good thing.
However, I see no such advantage in the case we are talking about. Harshman says, and you seem to be saying the same thing, that saying that bears are fish, precisely because it sounds counterintuitive, will generate puzzlement and interest in why the scientist is saying that, and that this could lead to understanding and accepting evolution. Well, I grant that it might have that effect in some cases. But exactly the same thing can be achieved without doing that. You can teach people that bears, and human beings, descended from primitive fish that lived hundreds of millions of years ago, without ever saying “bears are fish” or “humans are fish.” I read about evolution from a very early age (I was reading books about dinosaurs before I started kindergarten), and I understood that scientists thought that human beings had descended from earlier forms – simpler mammalian forms, reptilian forms, amphibian forms, fish forms. None of the books from which I learned this ever said: “bears are fish” or “you are a fish.” I needed no “shock treatment”, no paradoxical-sounding statements such as “you are really a fish”, in order to understand the notion of common descent. If no human being ever uttered the phrase “bears are fish” or “humans are fish”, the current theory of evolution could still be taught clearly and precisely. So, whereas, in the case of physics, adopting a changed meaning of “work” is necessary even to do physics, in the case of biology, it isn’t necessary to say “people are fish” (as opposed to, “people descended from fish”) in order to understand evolution.
I think we are getting hung up on the term Osteichthyes. Let me explain. When I first learned about evolution, nearly 60 years ago, none of the popular reference books, not even those written by biologists, used the cladistic terminology and diagrams that are used nowadays. (I don’t even know if they were generally used for in-house discussion by evolutionary biologists that long ago, but that’s a side point.) Under the classification I learned, Osteichthyes was a “Class”, not a “clade”, and the Actinopterygii were a Sub-Class, not a Class. So the categories have shifted around somewhat. I suspect that in this discussion I have unintentionally been shifting back and forth in my mind between Osteichthyes as the older Class (which excluded Mammalia, Aves, etc.) and Osteichthyes as the newer “clade” (which includes those other groups), and that may have led to lack of clarity in my exposition. If so, I apologize.
Yes, you’re right, that is what would happen, but of course, that’s a problem. Once the scientist says that “Osteichthyes” means “bony fish,” then the layman will say, “But bears aren’t fish! They don’t have fins, gills, scales, etc. And fish don’t have fur or warm blood. So why would you use such a name? Why not invent a NEW term, one that doesn’t have overtones of fish, mammal, bird, etc., a term of a more general nature, that captures the common elements of all the animals you’re trying to group?” And that would be a reasonable question.
Of course, your answer will be that biologists use the term for “bony fish” to characterize a much wider group of animals, because genealogically speaking, it was bony fish from whom those other groups sprang. But that still will strike people as odd, not because they don’t grasp the evolutionary relationship – they do – but because most people think that terms should try to capture the characteristics of the things they name, not their history.
Nobody says “television is radio” on the grounds that television was a later development of the use of radio waves, and thus in a sense “descended from” radio. And nobody says “motorcycles are cars,” on the grounds that they historically borrowed elements (internal combustion engine connected with wheels) that first took shape in cars. In most areas of life, we use definitions to indicate a distinctive description, not to record a historical relationship. So the biologist, in saying, not just that bears descended from bony fish (which the layman “gets” without a problem), but are bony fish, sounds as if he’s twisting language in order to line things up with a historical hypothesis, rather than using language to describe the characteristics of things. He sacrifices descriptive utility for the sake of recording a historical connection. Is there any other natural science in which terminology is controlled by such a priority?
It isn’t wrong in everyday language to say that Spanish is a Romance language, or a Latin-based language, or a Latin-derived language, or a language from the Latin family. What would be wrong in everyday language would be to say that Spanish is Latin. I think I was very clear about that.
No, it’s a side-point. I could completely abandon it, and all my discussion above would still hold water. As for you, I don’t know you well enough to say, but I’ll take your word for it that you have no culture-war motivation in using terms in the way that you do. About others, both here and elsewhere, I’m not so sure. But as I say, I don’t need the point to establish my main point, which is about the questionable utility of certain expressions and terms of classification.
No, that wasn’t my point at all. For the record, I’m against political correctness in all its guises, and against almost any form of censorship. I’m not saying that people shouldn’t deliberately try to offend anti-evolutionists, if that’s what they want to do. I’m just saying that if they do take pleasure in irritating anti-evolutionists, they should admit that they take pleasure in it. And if they do choose their expressions at least in part for culture-war purposes, they should admit that. I’m not advocating policing language; I’m advocating only complete transparency regarding agendas. But anyhow, all of this is a side-issue, so we should just let it drop.