I know there was one (the third) but was informed of the two others as well: Clarke’s Three Laws.
Clarke’s first law: When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
Clarke’s second law: The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
Clarke’s third law: Any sufficiently advanced technology is indistinguishable from magic.