‘What’ll it be, Mr. Gates?’

So Bill Gates walks into a bar ….

No, it’s not the beginning of one of those bar jokes — although it should be — but rather a central point in Paul Krugman’s New York Times column this morning that chastises Treasury Secretary John Snow for gilding the truth about income inequality in this country.

Since Krugman’s columns are squirreled away behind his newspaper’s TimesSelect wall, I’ll share the Gates part here.

Krugman: “I find it helpful to illustrate what’s going on with a hypothetical example: Say 10 middle-class guys are sitting in a bar. Then the richest guy leaves, and Bill Gates walks in.”

“Because the richest guy in the bar is now much richer than before, the average income in the bar soars. But the income of the nine men who aren’t Bill Gates hasn’t increased, and no amount of repeating ‘But average income is up!’ will convince them that they’re better off.”

Only problem with the hypothetical is that it’s just too difficult to imagine Bill Gates walking into a bar.