There are many theories, all unproved.

But he warned: "Dropping Medicare into an untested new system, based on an unproved theory about how to deliver health care, would be very controversial.

A counterespionage official said Wednesday that the inquiry into the documents, which were intended to show that Iraq was seeking uranium for a nuclear weapons program, had yielded some intriguing but unproved theories.

But the creationists insist that evolution remains an unproved theory that attacks the heart of their faith.

There are also enough unproved theories in the publishing industry to fill a paperback chapter.

For decades, therapists of various kinds have put forward one unproved theory after another to explain personal unhappiness, dissatisfaction or serious psychological dysfunction.

Researchers caution that these experiments are in very early stages and are based on unproved theories.

Or how about all those idiots who persist in calling evolution an "unproved theory."

You're asking me to destroy it on the basis of speculations and unproved theories.

Bluntly, we are using one unproved theory to support another which is unscientific--we have no proof.