Niven's laws were named after science fiction author Larry Niven, who has periodically published them as "how the Universe works" as far as he can tell. These were most recently rewritten on January 29, 2002 (and published in Analog magazine in the November 2002 issue). Among the rules are:

Others

Niven's Law (Time travel)

A different law is given this name in Niven's essay "The Theory and Practice of Time Travel": Hans Moravec glosses this version of Niven's Law as follows: Ryan North examines this law in Dinosaur Comics #1818. This proposition is also extensively examined in James P. Hogan's Thrice Upon a Time.

Niven's Law (re: Clarke's Third Law)

Niven's Law is also a term given to the converse of Clarke's third law, so Niven's Law reads: "Any sufficiently advanced magic is indistinguishable from technology." However, it has also been credited as being from Terry Pratchett. Keystone Folklore identifies it as a "fan-composed corollary slogan" of Arthur C. Clarke fans. Gregory Benford in his January 30, 2013 "Variations on Clarke's Third Law" identifies it as a corollary to Clarke’s third law, Both Clarke's Third Law and Niven's Law are referenced in part 2 of the serial Battlefield from season 26 of Doctor Who, first aired September 13, 1989. In this episode, the Doctor and his companion Ace have entered a trans-dimensional spaceship. While discussing the ship itself, the Doctor asks his companion if she knows Clarke's Law, which she then recites: "Any advanced form of technology is indistinguishable from magic." The Doctor replies that the reverse is true and Ace voices this, working through the inverse, "any advanced form of magic is indistinguishable from technology."

Niven's Laws (stories)

Niven's Laws is also the title of a 1984 collection of Niven's short stories. Included in the 1989 collection N-Space are six laws titled Niven's Laws for Writers. They are: In the acknowledgments of his 2003 novel Conquistador, S.M. Stirling wrote:

Niven's Laws (from Known Space)

Drawn from Known Space: The Future Worlds of Larry Niven 2. Never stand next to someone who is throwing shit at an armed man. 2. How to make money for a worthy cause. 3. Special Interest Liberation. In November 2002 the above list was published to Analog Magazine but with slightly different numbering and new commentary. The "The world's dullest subjects" entry was removed, and a new final entry "Never let a waiter escape." was added to the end.