Clarke's First Law was proposed by Arthur C. Clarke in the essay "Hazards of Prophecy: The Failure of Imagination", in Profiles of the Future (1962).
The second law is offered as a simple observation in the same essay. Its status as Clarke's Second Law was conferred by others. In a 1973 revision of Profiles of the Future, Clarke acknowledged the Second Law and proposed the Third. "As three laws were good enough for Newton, I have modestly decided to stop there".
The Third Law is the best known and most widely cited, and appears in Clarke's 1973 revision of "Hazards of Prophecy: The Failure of Imagination". It echos a statement in a 1942 story by Leigh Brackett: "Witchcraft to the ignorant, ... simple science to the learned". Even earlier examples of this sentiment may be found in Wild Talents (1932) by the author Charles Fort, where he makes the statement: "...a performance that may some day be considered understandable, but that, in these primitive times, so transcends what is said to be the known that it is what I mean by magic."
A fourth law has been added to the canon, despite Sir Arthur Clarke's declared intention of not going one better than Sir Isaac Newton. Geoff Holder quotes: "For every expert, there is an equal and opposite expert" in his book 101 Things to Do with a Stone Circle (The History Press, 2009), and offers as his source Arthur C. Clarke's Profiles of the Future (new edition, 1999).
Snowclones and variations of the third law
There exist a number of snowclones and variations of the third law
^J. Porter Clark (16 November 1994). "Clark's Law". Newsgroup: alt.news.misc. Retrieved 10 December 2014. They were apologetic and seemed sincere, but sufficiently advanced cluelessness is indistinguishable from malice. 8-)