“There are certain truths that, in themselves, are as dangerous as any advanced technology.”

This is derived from the third of Arthur C. Clarke's three laws : "Any sufficiently advanced technology is indistinguishable from magic." There are other variants which had inverted this including one known as Gehm's corollary http://www-users.cs.york.ac.uk/susan/cyc/l/law.htm, published several years earlier : "Any technology distinguishable from magic is insufficiently advanced." The earliest variant seems to be "Any sufficiently advanced magic is indistinguishable from technology." It has been called "Niven's Law" and attributed to Larry Niven by some, and to Terry Pratchett by others, but without any citation of an original source in either case — the earliest occurrence yet located is an anonymous one in Keystone Folklore (1984) by the Pennsylvania Folklore Society.
Foundation's Fear (1997)

Anonymous saying, this is an inversion of the third of Arthur C. Clarke's three laws : "Any sufficiently advanced technology is indistinguishable from magic." It has been attributed to Niven, and even called "Niven's Law" by some, and to Terry Pratchett by others, but without any citation of an original source in either case, and the earliest occurrence yet located is in Keystone Folklore (1984) by the Pennsylvania Folklore Society.
Misattributed

Source: An Erotic Beyond: Sade

Profiles of the Future (revised edition, 1973)
On Clarke's Laws
Source: Profiles of the Future: An Inquiry Into the Limits of the Possible

The Transhumanism Handbook, 2019

Short Fiction, Catch that Zeppelin! (1975)

From Hawking's article A Brief History of Relativity http://www.time.com/time/magazine/article/0,9171,993018-6,00.html, in Time magazine (31 December 1999)

2006, 2006 International Qods Conference address

Source: The Other America (1962), Appendix, sct. 1