This is beginning to change, but not for the better. Instead of shouting each other down the way they did on “Crossfire,” the new pundits are more apt to sneer and mock in the style of Jon Stewart. There’s little to be gained in arguing with an opponent but much to be gained by mocking him. What this means in practice is that we tend to seek out news and commentary that more or less reflects our own opinions back to us. Reading the news becomes an exercise in confirmation bias.

The proliferation of online opinion journals has been partly a welcome and positive good. But it’s also narrowed our shared cultural vocabulary, reducing the number and kinds of authorities to which members of different ideological camps may appeal. This very essay, for example, by virtue of being published in The Federalist, will for many otherwise intelligent and broad-minded people be enough to dismiss it out of hand. You simply can’t trust those people. (What’s more, media loyalties have by now become powerful signaling devices. Posting a piece to one’s Facebook or Twitter feed, if it comes from the wrong sort of site, could provoke stern rebukes from one’s peers.)

A certain logic sets in: some writers, and perhaps a great many of them, are not to be read because they’re not making good-faith arguments. Their publishers are in the business of advancing an agenda, probably at a financier’s request, and they all can be safely ignored. So we arrive at this unhappy place: why would a loyal reader of (or writer for), say, The New Republic ever read anything in The Federalist or National Review, except to sneer at it, mock its author, and impugn the motives of its publisher? The same goes for conservatives who refuse to read the New York Times or listen to NPR. Ignorance of the other’s argument, in this case, is a point of pride. The enemy is dangerous, after all, and must be stopped, not argued with, not taken seriously.

This is even happening within our major political parties. They do not want to hear what others have to say.