The key section of the article is the last one, about
"the erosion of our sense of [national]
identity, in which fair play, equality of opportunity, and a sense of community are so important."The author, Joseph Stiglitz [1], doesn't explain how inequality of wealth alone causes such erosion. On its own, inequality very well might not.
But other factors might be at work as well. Consider the effects of envy, or more precisely, "relative deprivation" [2]. There's been research indicating that no matter how well off humans are on an absolute scale, we tend to become dissatisfied when we perceive that we're worse off than our neighbors; we tend to believe we're somehow entitled to do at least as well, or even better, than they. (See also "keeping up with the Joneses.")
Envy is probably a product of natural selection; it can be a useful motivator, at least when properly channeled.
On the other hand, envy might be less adaptive in an era of global mass communications. It's certainly easier today for millions of people to become aware of, and then (perhaps subconsciously) resentful of, others who seem better off than they.
So it could be that we have a combination of causes at work: Increasing public awareness of wealth inequality leads to increased envy, which might indeed start to erode the social fabric.
If this turns out to be the case, what could we do about it?
Some might say humanity should be less envious, that people should just accept inequalities of wealth as natural consequences of their own limitations. History suggests that they -- or should I say, we -- probably won't.
[1] Joseph Stiglitz, professor at Columbia, former chief economist of the World Bank, Nobel Memorial Prize in Economics 2001 http://en.wikipedia.org/wiki/Joseph_Stiglitz
[2] http://en.wikipedia.org/wiki/Relative_deprivation