‘The best way to predict the future is to design it” has been credited since at least 2004 to futurst Buckminster Fuller (1895-1983). There is no evidence that Fuller ever said it.
 
Hungarian physicist Denis Gabor, in his book Inventing the Future (1963), wrote, “The future cannot be predicted, but futures can be invented.” American computer scientist Alan Kay is credited with having said in 1971, “The best way to predict the future is to invent it.”
 
[“We Cannot Predict the Future, But We Can Invent It” was investigated on September 27, 2012 by the Quote Investigator.]
     
 
Wikipedia: Dennis Gabor
Dennis Gabor CBE, FRS (original Hungarian name: Gábor Dénes; 5 June 1900 – 8 February 1979) was a Hungarian electrical engineer and physicist, most notable for inventing holography, for which he later received the 1971 Nobel Prize in Physics.
 
Wikipedia: Alan Kay
Alan Curtis Kay (born May 17, 1940) is an American computer scientist. He has been elected a Fellow of the American Academy of Arts and Sciences, the National Academy of Engineering, and the Royal Society of Arts. He is best known for his pioneering work on object-oriented programming and windowing graphical user interface design, and for coining the phrase, “The best way to predict the future is to invent it.”
 
He is the president of the Viewpoints Research Institute, and an Adjunct Professor of Computer Science at the University of California, Los Angeles. He is also on the advisory board of TTI/Vanguard. Until mid-2005, he was a Senior Fellow at HP Labs, a Visiting Professor at Kyoto University, and an Adjunct Professor at the Massachusetts Institute of Technology (MIT). After 10 years at Xerox PARC, Kay became Atari’s chief scientist for three years.
 
Google Books
Inventing the Future
By Dennis Gabor
London: Secker & Warburg
1963
Pg. 207:
The future cannot be predicted, but futures can be invented. It was man’s ability to invent which has made human society what it is. The mental processes of inventions are still mysterious. They are rational but not logical, that is to say, not deductive.
 
Google Books
28 March 1963, New Scientist, “Books: How to be dignified though useless” by Nigel Calder, pg. 712, col.s 1-2::
Inventing the Future. By Dennis Gabor.
(...)
His basic approach is that we cannot predict the future, but we can invent it, hence his title. he is essentially optimistic.
 
16 August 1966, The Evening Times (Trenton, NJ), “TV In Review: Long Look Ahead” by Robert Musel, pg. 22, cols. 1-2:
“We are not going to predict the world to come. As someone once said: The future cannot be predicted but futures can be invented.”
(Burton Benjamin, executive producer of CBS-TV’s The 21st Century.—ed.)
 
6 April 1973, Lubbock (TX) Avalanche-Journal, “Engineer Appeals To Man To ‘Invent’ Livable Future” by Irving Bengelsdorf (ESN), pg. 8-F, col. 1:
Dr. Gabor, Hungarian-born British electrical engineer who was awarded the 1971 Nobel prize in physics for his development of holography, has written and lectured widely that although it is impossible to predict the future, it is possible to invent it.
 
22 July 1982, Daily Intelligencer (Doylestown, PA), “‘Tron” has encouraging message: man can control computers” by David Sterritt (Christian Science Monitor), pg. 34, col. 1:
“It’s like saying the best way to predict the future is to create it,” Lisberger says.
(Steven Lisberger, director of the movie Tron.—ed.)
 
Google Books
Fall/Winter 1983, EDUCOM Bulletin,  “Learning vs. Teaching with Educational Technologies” by Alan Kay, pg. 17, col. 2:
So, here are the four ideas. First, the best way to predict the future is to invent it, because we can then say, “the future’s there for us to shape — we’re not helpless.” As long as we don’t violate too many of Newton’s laws, we can probably make new technology work out. We should decide what we want and then make it happen.
 
Google Books
11 June 1984, InfoWorld, pg. 62, col. 2:
“The best way to predict the future is to invent it — that’s what we used to tell them at Xerox.”
(Alan Kay.—ed.)
 
15 December 1984, Farmington (NM) Daily Times, “Little Seeks GOP Nod For Governor” by Scott Sandlin, pg. 1, col. 6:
“The best way to predict the future is to create it.”
(Farmington insurance agent Jack Little.—ed.)
   
Google Books
Discovering Homeopathy:
Medicine for the 21st Century
By Dana Ullman
Berkeley, CA: North Atlantic Books
1991
Pg. XXXIII:
Alan Kay, the founder of the Atari Corporation, once said, “The best way to predict the future is to invent it.”
 
Google Books
The Best of OPL II:
Selected Readings from the One-Person Library, 1989-1994
Edited by Andrew Berner and Guy St. Clair
Washington, DC: Special Libraries Association
1996
Pg. 334:
For as futurist Clement Bezold wisely noted, “the best way to predict the future is to create it.”
 
smalltalk.org
The Full Alan Kay Quote
“Don’t worry about what anybody else is going to do… The best way to predict the future is to invent it. Really smart people with reasonable funding can do just about anything that doesn’t violate too many of Newton’s Laws!”
— Alan Kay in 1971,
inventor of Smalltalk which was the inspiration and technical basis for the MacIntosh and subsequent windowing based systems (NextStep, Microsoft Windows 3.1/95/98/NT, X-Windows, Motif, etc…).
 
Alan on Alan
“The origin of the quote came from an early meeting in 1971 of PARC, Palo Alto Research Center, folks and the Xerox planners. In a fit of passion I uttered the quote!”.
— Alan Kay, in an email on Sept 17, 1998 to Peter W. Lount
   
Google Books
Edison in the Boardroom:
How Leading Companies Realize Value from Their Intellectual Assets
By Julie L. Davis and Suzanne S. Harrison
New York, NY: John Wiley & Sons, Inc.
2001
Pg. 126:
As George Pake, founder of Xerox PARC, once said, “The best way to predict the future is to invent it.”
 
BioInspire (July 17, 2004)
“The best way to predict the future is to design it”
—Buckminster Fuller
 
OCLC WorldCat record
The best way to predict the future is to create it
Author: Andreas Lång; Sida.
Publisher: Stockholm : Sida, 2005.
Edition/Format:   Book : Conference publication : Swedish
   
ArchitectureWeek
April 19, 2006
Energy Concerns Mainstream
by Evan H. Shu, FAIA
In March 2006, architect and planner Bob Berkebile, FAIA addressed an overflow audience at the Building Energy ‘06 conference in Boston. He gave a stirring call to arms, saying that this was a powerful moment in human history.
 
In describing the role of design professionals in solving the problems of climate change, Berkebile of BNIM Architects quoted his mentor, Buckminster Fuller: “the best way to predict the future is to design it.”
 
Google Books
Architectural Security Codes and Guidelines:
Best Practices for Today’s Construction Challenges
By Robert C. Wible
New York, NY: McGraw-Hill
2007
Pg. 281:
The best way to predict the future is to design it. — Buckminster Fuller