Prior to that, Bell had only an unproven theory.

While he has some evidence to support his hypothesis, it is still just one of many unproven theories.

This bill "would have required that when public schools refer to evolution that it be identified as an unproven theory."

This has led to various unproven theories as to why the accident occurred.

However, it was based on unproven theory, with little or no social research to support it.

However, the origin of the creek's name is unclear, with several unproven theories existing.

What is different is Yellowstone's experimentation with the unproven "theory of natural regulation."

And behind it all, the unproven theory of central queens or seed-mothers, perhaps reflecting human needs for answers more than any reality.

There is also an unproven theory that the design of the papal tiara would have been based on a toque.

Man-made global warming is an unproven theory based on manipulative statistics.