Erasmus tells the story of a semiliterate priest who, returning from reciting mass, is chastised by a visiting colleague for using the word "mumpsimus." "It doesn't exist in the language," his colleague explained. "The correct form is 'sumpsimus'." The offending priest responded, "I've been saying 'mumpsimus' for 40 years, and I'm not going to change now to 'sumpsimus,' correct or not."

Dan Rather is a classic mumpsimus, claiming, against the facts acknowledged by the whole world, including the residents of Mars and Venus, that the forged documents regarding President Bush's National Guard service may yet prove to be authentic, which would also authenticate his flagging career.

Rather, by knowing that he is flouting the facts, is guilty of committing a mumpsimus and, at the same time, raises the issue of "checkbook journalism," the holiest dogma of the journalistic priesthood.

No journalistic rule is as strictly enforced or, indeed, worshipped as the rule that the media must never pay for its product. Indeed, the media would rather do without an important story or feature than pay the source of it, unless they are buying it from another media company. The media that does pay for first-person stories -- the Enquirer, Star and other supermarket tabloids -- are regarded with contempt by the establishment.

The supposed reason for this policy is that if you pay the source of one of these stories -- say , the woman who survives a shark attack or a building fire -- he or she might exaggerate the story in order to get a high fee. By dubbing it "checkbook journalism," the implication is that money is the sole driving force behind people who sell their first-hand accounts to the tabloids.

But of course "checkbook journalism" also pervades the established press. The anchors and staff reporters get paid for their efforts and the more scoops they achieve, the more leverage they have at contract renewal time for higher pay. In Rather's case, his biggest defense is that he didn't exploit the forged documents in order to tarnish the Bush image but, rather, to scoop the competition. This is but one more example of the media flouting the rules for competitive reasons. Plagiarism, fake datelines, misleading credits -- all have been used time and again by the major media companies, from The New York Times on down (or, these days, up).

And the logic is totally against the "checkbook journalism" policy. Who is more likely to tamper with the truth: the staffer whose entire career depends on the space he gets in the media over a period of years, or the Joe Citizen who by good or bad luck falls into a once-in-a-lifetime experience that has a market value (and whose experience can be checked out by a career journalist).

This refusal to pay for product, set forth on high ethical grounds, is one of the great scams. (Newspapers are good at this, refusing to print good news about branded products unless the manufacturer pays for this news in an ad. The rule is broken for pharmaceuticals that pioneer new therapies or cures, but for very few other products, especially household products. The media has fostered this policy as if it is based on high ethics, rather than on simple business practice.)

The absurdity of the "checkbook journalism" prohibition is that newspaper editors don't attack book publishers as "checkbook publishers." Of course they are. They don't even try to persuade authors to give them their books for free. And if the source of a first-hand story is a good writer, the newspaper might pay him to write his or her story for it or, in some cases, to engage a professional writer to ghost it. All of this just to avoid paying for the product cleanly and directly. Would it add to the media's costs? Of course. Just as buying leather adds to the cost of making shoes.

This doesn't mean that all first-person accounts or interviews have to be paid for. But to have a policy that is religiously enforced is unfair and counterproductive. Many stories are lost because of it.

The author, a TCS contributor, is a New York media consultant who for many years was Senior Vice President of United Media for Syndication.