Shouldn't knowledge be described, not defined?

This is a response to a comment: "Any argument that shows that we can't know anything has a misguided concept of knowledge." I think the poster misunderstood my point (my bad) - my complaint is not about sceptical conclusions.

My complaint is with assumptions: Nozick starts his argument with the assumption that it's possible for us to be systematically wrong. I think scepticism is a symptom of a deeper problem, not a problem that itself needs to be solved, so I don't see how Nozick helps.

The problem I have with Nozick and his attempts to get around the troubles of defining knowledge as TJB+ is not his success (or maybe lack thereof) in coming up with a definition. From what I can understand, his definition is pretty water-tight. My problem is that he's been very successful in a project which I can't understand the value of.

I think that, whatever it means to have knowledge, the concept means what it does as a result of social interactions that render the word meaningful: the word "knowledge" means whatever has to obtain in order for the sentences containing the word to be true; and the particular meaning comes from the social interactions involving the word between people who live in a world.

That's pretty much Davidson plus whatever it takes to eliminate the "wrong" theories of meaning - there's a blog post related to this over here. Or at least, my own mangled understanding of the issue.

The thing is, these social interactions don't have much to do with truth (except insofar as utterances are nearly all true), and less stil to do with "counterfactuals" (unless you are living in a philosophy department, perhaps). Since Nozick has developed his concept of knowledge using his own concepts, I don't see how he has helped explain what it means to have knowledge: he has created a concept, rather than explained one.

The concept Nozick has created may even be co-extensive with knowledge; it may even be co-extensive enough that we can compare what we think we know with his counterfactual scheme, and come to some conclusion about whether in fact we know this thing we think we know or not. At least, it would be if we could travel to possible worlds.

But that still doesn't mean he has told us anything about this peculiar condition of knowing which is inflicted on human beings; that is there one minute yet disintegrates so readily under the sceptical ruminations of a Frenchman in a cellar. For my part, when I say I "know" something, it has bugger-all to do with counterfactuals. (Trust me.)

Why should I be interested in a theory of knowledge that explains a concept without any reference to my use of the word?