That was exactly my first thought. But have you read Quine's arguments?

Yes, about natural kinds. We discovered that there were mammals, we did not invent that classification. And we discovered that whales are mammals and they are not fish. It was an error to believe that whales are fish just because they had the superficial aspects of fish. Similarly in the case of porpoises. I think that is right, don't you?

That was exactly my first thought. But have you read Quine's arguments?

Kennethamy mentioned the natural kinds concept. Are there other reasons Quine had for not thinking that classification is ultimately arbitrary: that we set up rules for classifying things because of our needs and interests?

I am referring to the link that was posted by ughaibu on the last page. Did you read that argument?

The referent of the term, "three" is what it is, and even should it have ever been the case that we never discovered it, it would remain what it is;

after all, truth is independent of knowledge.

What you have just suggested is the invention of a completely different numbering system with numerals that not only have different meanings but different referents as well

There are multiple ways to describe the world around us.

No. Sorry, but I take the view that if a poster thinks an argument applies to the discussion at hand, they should at least be able to provide a brief summary of it themselves in their own words rather than just pointing to a link.

I don't mean to imply you are wrong, but what makes you say this? Where does the number three exist in the world to be considered a referent?

That would only be true if the referent of "three" is a mind-independent entity, like a planet is But our concept of numbers is different than our concept of substances like planets.

I hope this isn't meant to be a story concerning my behaviour.

No. Sorry for that implication.
I don't at all object to links being placed to help provide information, as you did. But if a poster tells me that I need to follow a link because it invalidates or disproves a point or claim I was making without at least giving me an idea of why it invalidates or disproves my claim, I don't often follow their advice.

Thanks for specifying Quine's argument. Since I think that ultimately language is arbirtrary and not beholden to reality, I find little reason for accepting the concept of natural kinds.

Of course, the needs and interests of science are to classify things in accordance with what is perceived to be reality.

---------- Post added 03-04-2010 at 12:12 PM ----------

But if a poster tells me that I need to follow a link because it invalidates or disproves a point or claim I was making without at least giving me an idea of why it invalidates or disproves my claim, I don't often follow their advice.

But who told you that the link invalidates or disproves a claim you've made? I was merely asking if you read the argument so we all could discuss it here (I'm personally having trouble even understanding it). If you would be so kind as to refer back to the last couple pages, you would see that the claims you've made I agree with. And I thought I voiced so.

Even if language were arbitrary (and I do think you mean conventional, not arbitrary), why would that show there were no natural kinds? If language is conventional, that doesn't show there are no chairs and tables, does it?

Of course, language is a series of conventions. There is nothing about chairs that force us to call them, "chairs". After all, the French do not call them, "chairs", they call them, "chaises". But why should that fact mean there are no chairs? And why should the fact that language is conventional mean that there are no natural kinds?

Language is a series of forms presented in a conventional way so as to best communicate the message, which is truth..

Sorry for misunderstanding you. Will try and take a close look at the site later today.

What truth does the sentence, "What time is it?" communicate?

Even if language were arbitrary (and I do think you mean conventional, not arbitrary), why would that show there were no natural kinds? If language is conventional, that doesn't show there are no chairs and tables, does it?

Of course, language is a series of conventions. There is nothing about chairs that force us to call them, "chairs". After all, the French do not call them, "chairs", they call them, "chaises". But why should that fact mean there are no chairs? And why should the fact that language is conventional mean that there are no natural kinds?

What truth does the sentence, "What time is it?" communicate?

The way I see it is that I have a concept of the number three, and that is mind dependent (or abstract in one sense), but "three" refers not to my concept of the number three (as "my concept of the number three" refers to that) but instead refers to the number three (which is not abstract in that same sense but abstract in the other sense), as the number three is a class, and a class is a not abstract in the mind dependent sense.

There may well be different conceptions of 'natural kind' that I am not aware of. But the one I find fault with is the conception that it is the real essence of a thing that determines the meaning of the natural kind name. That science discovers the real meaning of a word rather than the meaning being stipulated.

I think it an illusion that science can discover the real meaning of words like 'gold' or 'water'. The meaning of a word is determined by convention not by discovery. However, a discovery may be elevated into convention by agreement on a new rule for using a word. We place a high value on scientific discovery in our culture, so such an elevation is quite common.

Certainly I agree with you that we could have called a chair a "horse" instead of a "chair". In the same way, we could have called the Pawns in chess "Peasants" instead. But it is the rules we determine for the use of "horse" and "peasent" that are relevant here. Not simply using a different combination of letters for naming something.