PAT ROBERTSON has been saying some pretty psychedelic things. First came his apparently evidence-less charge during a New Hampshire debate that Soviet missiles had been newly placed in Cuba. Next came the apparently equally unsubstantiated charge that Vice President Bush's campaign had arranged to have the news of television evangelist Jimmy Swaggart's fun and games made public just two weeks before the Super Tuesday contest. And finally (at least in this series) comes the claim that Mr. Robertson's Christian Broadcasting Network knew the location of American hostages after they had been captured in Lebanon and made this available to the administration, which failed to act.

These assertions have several things in common. Mr. Robertson produced no proof for any of them. The pool of evidence for the missile charge melted down to some Senate staffer's rather different words; the charges against the Bush campaign were sheer speculation; CBN, it appears, only knew the hostages' location when they were on the tarmac. Then, Mr. Robertson tried to worm out from under each statement. He claimed that he was not making charges about the missiles and the Bush campaign, just raising questions, though of course in these circumstances to point the finger is to make the charge. On the hostages, he argued plaintively that "they want me to be accompanied by a press aide, a lawyer and a librarian with at least a thousand volumes to back up every word I've said." No, Mr. Robertson, they just would like you to know what you're talking about.

George Bush dismissed the charge that his campaign engineered the Swaggart revelations as "crazy" and "absurd." President Reagan said it was "strange" that Mr. Robertson didn't tell the administration where the hostages were if he knew. Mr. Robertson's statements seem designed to reinforce -- if they do not arise from -- a frame of mind that sees major events as turning on hidden conspiracies, dirty tricks and secret evidence that those in power keep secret. Sometimes, of course, they do. But not usually, and in these cases the Robertson charges have been reckless.

Some speculate that the candidate is making bizarre statements to fire up his core supporters. Maybe. But what he surely is doing is diminishing any appeal he might have to the many potential Republican primary voters who like his stands on some issues but are put off by his inexperience and background and especially by his reckless way with the truth.