The law of continued failure: "The law of continued failure is the rule that says that if your country is incompetent enough to use a plaintext 9-numeric-digit password on all of your bank accounts and credit applications, your country is not competent enough to correct course after the next disaster in which a hundred million passwords are revealed. A civilization competent enough to correct course in response to that prod, to react to it the way you’d want them to react, is competent enough not to make the mistake in the first place. When a system fails massively and obviously, rather than subtly and at the very edges of competence, the next prod is not going to cause the system to suddenly snap into doing things intelligently." (source)
Law of Earlier Failure: "compared to the interesting part of the problem where it's fun to imagine yourself failing, you usually fail before then, because of the many earlier boring points where it's possible to fail." (source)
Moore's Law of Mad Science: "Every 18 months, the minimum IQ to destroy the world drops by one point." (video, transcript)
Some other laws stated by Yudkowsky: