Some argue that no science of success is possible.

The fate of an enterprise or project, the contention goes, is determined by too many variables to be predictable. 

In business, there is advertising, word of mouth, the availability of capital, talent, and good old-fashioned luck. 

Some argue that no science of success is possible.
Some argue that no science of success is possible.

Successful people are not perfect. They are likely to be the first to tell you that. Some might even say they aren’t the luckiest people in the world.

One thing is clear, though. They do not quit. 

Here are 10 quotes from 10 people who didn’t give up:

1“In the end, a vision without the ability to execute it is probably a hallucination.” — Steve Case

Steve Case is an American entrepreneur, investor, and businessman. He is the former chief executive officer and chairman of America Online. Case is currently the CEO of Quantum Computer Services. (Photo: Robert Scoble/Flickr)

2“When you find an idea that you just can’t stop thinking about, that’s probably a good one to pursue.” — Josh James

Josh James is an American entrepreneur. He is the founder and CEO of Domo. James previously co-founded and served as CEO of Omniture, the web analytics company. (Photo: Stuart Isset/Fortune Media Live/Flickr)

3“It’s not about ideas. It’s about making ideas happen.” — Scott Belsky

Scott Belsky is an American entrepreneur, author and early-stage investor. He is best known for co-creating the online portfolio platform, Behance, Inc. Belsky was included in Fast Company’s “100 Most Creative People in Business” in 2010.

4Chase the vision, not the money, the money will end up following you.” — Tony Hsieh

Tony Hsieh is an American internet entrepreneur and venture capitalist. He is the CEO of the online shoe and clothing company Zappos. (Malong & Company Photography/Flickr)

5“Ideas are easy. Implementation is hard.” — Guy Kawasaki

Guy Kawasaki is an American marketing specialist, author, and Silicon Valley venture capitalist. He was one of the Apple employees originally responsible for marketing the Macintosh computer line in 1984 (Photo: Eric Solheim/Wikimedia Commons)

6“The best start-ups generally come from somebody needing to scratch an itch.” — Michael Arrington

Michael Arrington is the American founder and former co-editor of TechCrunch. Magazines such as Wired and Forbes have named Arrington one of the most powerful people on the Internet. (Photo: Joi Ito/Flickr)

7“Timing, perseverance, and ten years of trying will eventually make you look like an overnight success.” – Biz Stone

Christopher Isaac “Biz” Stone is an American entrepreneur who co-founded Twitter, among other Internet-based services. (Photo: Joi Ito/Flickr)

8“Success seems to be connected with action. Successful people keep moving. They make mistakes, but they don’t quit.” — Conrad Hilton

Conrad Nicholson Hilton was an American businessman and hotel magnate. He was the founder of the Hilton Hotels chain. Despite suffering a tremendous financial setback during the Great Depression, Hilton was able to build a hotel empire.

9“I never dreamed about success, I worked for it.” — Estée Lauder

Estée Lauder (left) co-founded her eponymous cosmetics company with her husband, Joseph Lauter. Lauder was the only woman on Time magazine’s 1998 list of the 20 most influential business geniuses of the 20th century. (Photo: Bill Sauro/World Journal Tribune/Wikimedia Commons)

10“Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time.” — Thomas Edison

Thomas Alva Edison was an American inventor and businessman. History describes him as America’s greatest inventor. Edison developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. (Photo: Louis Bachrach/Wikimedia Commons)