How do you know you're successful? Is it a place where you can arrive, like a point on the map, or only a direction you can continually head for, knowing you will never really get "there"? And what is success anyway? Is it wealth, a large car, a high valuation, a lot of income? Or is it something else? And if so, what?

In a series of thought-provoking talks, highly successful TED speakers from entrepreneurs to best-selling authors address the question of just what it means to be successful and how you can tell when you're there.

None of these talks is longer than about 17 minutes, most are under 10. If you obsess about success even a fraction as much as I do, they're well worth your time for the change in perspective they can bring. Here are some of the lessons I drew from watching:

1. Being successful doesn't mean you always succeed.

Art historian Sarah Lewis got a new understanding of success when she curated a retrospective of a famous artist and learned that not all that artist's works were great. Or even all that good. In fact, the artist had thrown some of her earlier efforts into the trash, they were so unsatisfactory. Success, Lewis argues, is not a destination but a fleeting moment. Whereas mastery-getting as good at something as you can possibly be-is a life's work.

2. Success is doing what you love.

After the blockbuster success of Eat, Pray, Love, author Elizabeth Gilbert faced a dilemma. Canny about the publishing world, she knew for a certainty that whatever book followed would meet with disdain from critics and would be a commercial failure compared with her first book.

What to do? Exactly what she did as a struggling diner waitress with a mailbox full of rejection slips. She said, "I'm going home," which to her meant back to the act of writing. When the next book did indeed bomb, its poor reception in the marketplace didn't rattle her, and when the one after that did better, that was nice. But either way, she says, she felt "bulletproof," because whatever happened, she would keep writing, and as long as she was writing, she was home.

That, she says, is the recipe for real success. "You've got to identify the best, worthiest thing that you love most, and then build your house right on top of it and don't budge from it. And if you should someday, somehow get vaulted out of your home by either great failure or great success, then your job is to fight your way back to that home the only way that it has ever been done, by putting your head down and performing with diligence and devotion and respect and reverence whatever the task is that love is calling forth from you next."

3. We must find ways to measure what really matters.

Chip Conley, founder (at 26!) of the Joie de Vivre hotel chain, and now head of Global Hospitality & Strategy for Airbnb, learned a powerful lesson from a Vietnamese immigrant who worked as a maid in an inner-city motel. For her, happiness and success came from the emotional connections she formed with her fellow employees and the people who stayed there. In other words, things that are intangible and difficult to measure.

Expanding on this idea, Conley discovered that while 94 percent of business leaders worldwide believe that intangibles are important to their success, only 5 percent have a way of measuring those intangibles. And yet, he says, you can measure intangibles, just as the king of Bhutan is doing with metrics that help determine the nation's "gross national happiness."

The rest of us should be doing the same, he says. "What one thing can you start counting today that actually would be meaningful in your life, whether it's your work life or your business life?"

It's an excellent question.

4. We should consider our eulogies and not just our rsums.

Bestselling author and New York Times columnist David Brooks tackles the thorny question of outward success vs. inner morals and the qualities that lead to each. "Rsum virtues," he says, are the skills we bring to the marketplace whereas "eulogy virtues" are questions of character-who we consistently are. "Most of us, including me, would say that the eulogy virtues are the more important," he says. "But at least in my case, are they the ones that I think about the most? And the answer is no."

It's a problem, he says, because the logic of each is completely at odds with the other. The logic of rsum virtues is much the same as that for a successful business: input leads to output, risk can bring reward. The logic of eulogy virtues is "inverse logic," he says. You have to give in order to receive, conquer desire in order to get what you want, forget yourself if you want to be fulfilled.

And while you achieve rsum virtues by building on your own strengths, he says, eulogy virtues come from conquering your own weaknesses. Find what he calls your "signature sin," he says, the one you commit over and over, and then wrestle with that sin for all you're worth. "Out of that wrestling, that suffering, then a depth of character is constructed."

2. We must resist the pressure to let others define success for us.

Philosopher Alain de Botton offers the mind-bending argument that materialism in modern society isn't about material things at all. It's about the desire we all have for love and approval and our sense that possessing material goods and worldly will bring them to us. "The next time you see somebody driving a Ferrari, don't think, 'This is somebody who is greedy,' he suggests. "Think, 'This is somebody who is incredibly vulnerable and in need of love.'"

For the rest of us, he recommends being aware of how we absorb ideas about what constitutes success from our parents, from television, marketing, advertising, and all the other influences in our lives. "These are hugely powerful forces that define what we want and how we view ourselves," he warns. "We are highly open to suggestion."

And so, he says, we should all do some soul-searching and make sure our desires about success truly are our own. "Because it's bad enough not getting what you want, but it's even worse to have an idea of what it is you want and find out at the end of a journey, that it isn't, in fact, what you wanted all along."