Sci-Fi writers seem to enjoy coining Laws: adages bearing their own names that live on past their appearances in Sci-Fi stories. Here are five of my favorites, plus one bonus law (actually a Principle) from the world of cartoons.

1. Hanlon's Razor (aka Hanlon's Law)

"Never attribute to malice that which can be adequately explained by stupidity." Ascribed to various authors, including Robert Heinlein. (Or perhaps it was Napoleon, or another candidate.) This law's name is also a take-off on Occam's Razor.

2. Sturgeon's Law

"Ninety percent of everything is crap." This adage came after a less successful "first law" by Sturgeon, "Nothing is always absolutely so." Read more on this bit of wisdom.

3. O'Toole's Corollary of Finagle's Law

Finagle's Law is a variant of Murphy's Law: Anything that can go wrong, will -- at the worst possible moment. It was popularized by John W. Campbell, Jr., editor of Astounding Science Fiction and Analog, as well as Larry Niven. But the much wackier O'Toole's Corollary of Finagle's Law is:

"The perversity of the Universe tends towards a maximum."

See also: the second law of thermodynamics.

4. Clarke's Three Laws

Arthur C. Clarke postulated three laws over his illustrious career. The third is by far the most famous:

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.

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. Second law: The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

The only way of discovering the limits of the possible is to venture a little way past them into the impossible. Third law: Any sufficiently advanced technology is indistinguishable from magic.

5. Asimov's Laws of Robotics

Forming the basis for Isaac Asimov's fictional universe, these laws for robotic behavior have been the source of much Sci-Fi drama (I, Robot anyone?):

First law: A robot may not harm a human being, or, through inaction, allow a human being to come to harm.

A robot may not harm a human being, or, through inaction, allow a human being to come to harm. Second law: A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law.

A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law. Third law: A robot must protect its own existence, as long as such protection does not conflict with the First or Second Law.

There's also a Zeroth Law.

6. The Dilbert Principle

Although Scott Adams isn't a Sci-Fi writer, his Dilbert Principle is worthy of an honorable mention: the most ineffective workers are systematically moved to the place where they can do the least damage: management.. (See also: the Peter principle.)

If that's not enough for you, check out Wikipedia's list of eponymous laws. (I'm particularly fond of Hofstadter's Law.)