Assertion

The mere fact of asserting a truth makes it true. "I say that X is true. Therefore X is true."

Being assertive is an adult way of behaving, stepping off the passive-aggressive continuum and stating a truth with conviction. This can be a very persuasive position, as it removes aggressive threat without capitulation, demonstrating maturity and apparent wisdom.

Assertion is often a veiled appeal to authority in that it makes the assumption that the person making the assertion is an expert or has a position of unassailable formal authority.