Yes words have meaning. But those meanings are in people’s heads and quite subjective. The words are not out there stuck to things or bounding things except that we impose them on reality with our minds, fabricating imaginary lines with our made up categories. With science, particularly with the use of mathematical measures we go beyond the limitations of our minds to language in order to see the universe more on its own terms, where there is a great deal more continuity than our words imply. All we have to do is visit another culture and see how they categorize things in completely different way in order to see how arbitrary our categories can be.
I suspect that the confusion of words with reality plays some part in the creationist rejection of evolution with their talk of “kinds” which are after all only the names and categories we have plastered onto the natural world. Even in the Biblical account, the natural world had not such names and categories in it already, but these were things Adam and Eve added to the world.
It is not that the words and language are unimportant – but often you cannot really see the importance of things until you fully understand what they are and how they change things so completely.
I am reminded of the that dialogue Susan has with Death in Terry Pratchett’s “The Hogsfather.”
Susan: Now tell me…
Death : What would have happened if you hadn’t saved him?
Susan : Yes.
Death : The sun would not have risen.
Susan : Then what would have happened?
Death : A mere ball of flaming gas would have illuminated the world.
Susan : All right, I’m not stupid. You’re saying that humans need fantasies to make life bearable.
Death : No. Humans need fantasy to be human. To be the place where the falling angel meets the rising ape.
Susan : With tooth fairies? Hogfathers?
Death : Yes. As practice, you have to start out learning to believe the little lies.
Susan : So we can believe the big ones?
Death : Yes. Justice, mercy, duty. That sort of thing.
Susan : They’re not the same at all!
Death : You think so? Then take the universe and grind it down to the finest powder and sieve it through the finest sieve and THEN show me one atom of justice, one molecule of mercy. And yet… you try to act as if there is some ideal order in the world. As if there is some… some rightness in the universe by which it may be judged.
Susan : But people have got to believe that, or what’s the point?
Death : You need to believe in things that aren’t true. How else can they become?
Now I am not agreeing with Death in this conversation entirely. And yet there is a lot of truth to what he is saying. I don’t think justice, mercy, duty (or love) are just lies. They are ideals which we aim for. In a sense you can say they are a bit like the boundaries by which living things separate themselves from their environment, even though it is the same molecules bouncing against each other. Yet there is an order we impose on the portion that is part of us. Likewise our mind imposes an order on the world in order to understand it. It is not entirely real but nor is it all just fantasy. By the means of science we can measure some of that order out there, and show that it works in predicting what we measure.