By I. P. LUPO

WASHINGTON, D.C. — You probably thought there was only one kind of fact — a true one.

False facts are not facts.

But here comes the Washington Post in an editorial today that proves this wrong. According to the Post, we now have “neutral facts” and, un-neutral, presumably biased facts.

This is a huge revelation. We now know that under the left’s catechism, facts, like opinions, can be legitimate or illegitimate. How can you tell which is which? Easy. Legitimate neutral facts are brought to you by Dupont Circle, what the Post calls “ordinary advocacy groups” and, of course, the liberal media. Illegitimate facts are brought to you by everyone else.

The first absurdity of the Post’s editorial is that objective truth can be de-legitimized by the politics of the group or person. This is the flip side of the liberal defense to their “facts” exposed as untrue.

In 1992, a Central American woman named Rigoberta Menchu won the Nobel Peace Prize for the non-fiction account of her miserable life of abject poverty and mistreatment by right-wing army torturers.

It turned out that she had made it all up. Actually, it turned out she didn’t even write the book.

The left’s defense was: “Well, even if it is not true, it could have been.”

In short, if your lies fit the left’s ideology, then they are not really untrue.

The Post’s editorial takes the Menchu defense one step further: The left’s lies are true, but the right’s facts are biased.

The second absurdity of the editorial is the belief that Dupont Circle gives you “facts,” let alone facts that are “neutral.” Dupont Circle’s “facts” include some of the great whoppers of all time:

– Men beat up women just before, during and after the Super Bowl (NOW et al);

– Elementary schools discriminate against girls and forever kill their self-esteem (National Association of University Women);

– Sandinistas, though Communist despots, were cute, misunderstood, and in any event better than Republicans (Brookings); and

– Eating anything is unsafe (Center for Science and the Public Interest).

Finally, the most insidious part of the Post’s thinking is its pervasive belief that left-wing advocacy groups are somehow “neutral.” No wonder the liberal media feed us multiple daily dishes of “studies,” as if they were news.

There is actually no need for any “study” because the findings are entirely predictable, based on the question and the group preparing the answer.

If there is bias, it is the Post’s for measuring the value of ideas based on the business model of those who generated them.

The particular issue in the Post editorial is whether an organization funded by food and cigarette companies has a right to ridicule the Centers for Disease Control’s overstatement of obesity deaths by a factor of more than four. The Post called the anti-CDC obesity hype ad a “simple-minded attack,” though not because anything about it was untrue.

Instead, it was soo stuuupid, because the group running the CDC-mocking ads has a self- interest and because the CDC study was criticized before it was released. Horrors.

As if the Dupont Circle crowd doesn’t have self-interests. And as if the Post does not go into Tarzan-like chest-beating when it publishes leaked copies of anything written by people with whom it disagrees.