Recently my dad made mention in conversation of the following Robert Heinlein quote: "One man's 'magic' is another man's engineering" and it reminded me of the quote from Arthur C. Clarke which I consider to be the "original" (true or not).
"Any sufficiently advanced technology is indistinguishable from magic."
When I was trying to verify the correct wording it turns out that this was the third of four "laws" that Clarke was known for. They are:
This however led to finding some parodies, rephrasing and related quotes that I enjoyed. So I thought I would list a couple here.
Leigh Brackett: "Witchcraft to the ignorant... Simple science to the learned."
Gibson's law: "For every PhD there is an equal and opposite PhD."
Larry Niven: "Any sufficiently advanced magic is indistinguishable from technology."
In the first non-Asimov Foundation novel, Foundation's Fear, the emperor declares, "If technology is distinguishable from magic, it is insufficiently advanced."