What is Education For?

I ran across the following post in Andrew Sullivan's website and it occurred to me that before we can begin to think about textbooks or texts or teacher quality or anything related to assessing education quality, we ought to determine what we mean by "education" and what purpose(s) and education is supposed to serve.

I think I know the answer to this, but do we believe in education for its own sake, or education that is supposed to increase earnings potential? Sullivan links to the following:

You know going back and forth with a few people about this education bubble issue, many thoughts occur to me, but none more important than this: education cannot survive on what I am horrified to find is the generally assumed model, that it exists for the purpose of increasing earning potential. To see an education, college or otherwise, as merely a way to increase the amount of money you make is a terrible corruption and fundamentally unsustainable. Education was never intended that way, and it cannot succeed on those grounds.
It never ceases to amaze and dismay me. This totalizing vision of mankind as homo economus, where absolutely every element of human life is reduced to the exchange of currency and resources, has vast, negative consequences. People see them every day, and yet nobody is willing to walk back from the path we're on.
I wonder if this comment matters for us. I imagine that a high percentage of people in the greater Houston area would argue that education is more essential to earnings potential, and "education for its own sake" is something they'd rather not have their tax dollars spent on. Perhaps we can cynically argue that education has never been for its own sake, it has always created opportunities for one group at the expense of another, but its still worth thinking about.

While we think about assessing the quality of the education our students receive, are we clear about what we want that education to do for our kids?