We write pages about Warren Buffett at The Motley Fool. We write about Philip Fisher, John Neff, Bill Miller, and other investing superstars, too. This is all to the good.

If you want to learn military history, you study Alexander, Napoleon, and Rommel. If you want to learn about investing, you study the strategies of those who succeeded.

Under the stewardship of Peter Lynch, $1,000 invested in Fidelity's Magellan Fund increased 2,700% to $28,000 over a 13-year period. That's a very respectable 29% compound average annual return. Ignoring the investing lessons of Lynch would be like boxing without ever watching tapes of Jack Dempsey or Floyd Patterson.

Warren Buffett stands atop this mound of great investing minds, not simply because of his remarkable success at Berkshire Hathaway (NYSE: BRK.A), but because he stops to teach along the way. In his annual reports, at Berkshire's annual shareholders' meetings, and in his occasional contributions to Fortune magazine, Buffett instructs.

Like any good teacher, he handles difficult material (for example, the use of EBITDA, corporate governance, and the accounting treatment of goodwill) with wit, clarity, and amazing common sense. It's hard to find a crisper piece of financial prose than Buffett's 1999 Fortune article explaining why investors are probably expecting too much from the stock market.

But I'm growing more aware of the risks of his approach based on the limits of my ability to imitate his methods. Specifically, his focused-portfolio approach, like that of John Maynard Keynes' and Fisher's, minimizes diversification, a dangerous game for the average investor.

Neither a professional nor an amateur tightrope walker requires a safety net to actually cross the wire, but it may make good sense for a professional to cross unprotected while it's senseless for the amateur to try when his life, or life savings, is at stake. This is why there are index funds. Just as the risk for each tightrope walker is different, the risk for each investor is different depending on experience, ability, and temperament. 

Let's assume Buffett's value investing technique works (I think it does), and that we have good reason to expect stocks to pay off long term (I think they will). There is some risk in both of these assumptions, but let's assume both are true.

The question is this: Can we imitate Buffett, or learn enough from his teachings to find success? I'm not as smart as Warren Buffett, but can't I imitate his techniques and have a very miniature version of his success?

This is where the road divides. Many people -- myself included -- who know a lot about Warren Buffett's investment style may not have a lick of his investment success because small differences in ability, temperament, and good fortune yield enormous differences in results. It's no easy job identifying companies with sustainable competitive advantages trading at reasonable prices. What's sustainable? What's reasonable?

Behind Buffett's charm is a mathematically gifted investor who worked with Ben Graham on Wall Street, mastered financial analysis, and spent most of his life as both a business owner and student of the investing game. Pick up a good book and you can get the gist of Buffett's investing strategy, but applying his stock picking principles, confidence, and personal discipline is another matter.

Buffett himself acknowledges the game has gotten harder, and that good ideas, like good parking spaces, are hard to find. Consider that Buffett spends all his time applying a great intellect to this effort and finds only a few good ideas each year, sometimes less than that. If we are less discerning or less insightful than Mr. Buffett, our ideas may not be good ones at all.

The emergence of index funds is basically a nod to this sobering reality. There may be a few great men and women who are highly skilled at picking stocks and capable of beating the market over the long term. But like great starting pitchers, there aren't many. The likelihood there's one at the head of your professionally managed portfolio is slim considering the number of U.S. funds.

If talent is stretched thin, and many fund managers who beat the averages over a one, two, or three year period are lucky rather than good, then the best bet for the average investor interested in stocks is a diversified group of index funds. Long conversations with Paul Commins have convinced me that much of what passes as investment skill in the stock market is indistinguishable from luck.

If this is the case, then one aspect of Buffett's, or Fisher's style of investing -- the focused portfolio -- is an imprudent strategy for the average investor, who doesn't have the time, acumen, experience, capital, or confidence to make the same big bets as Warren Buffett.

This is not an attack on Buffett. Much of what I know about investing comes from Graham or Buffett, or someone influenced by their thinking. I read everything Buffett writes and much of what's written about him. And since his approach makes the most sense to me, it has formed the centerpiece of my own investing strategy. I've used it to purchase the few stocks I own, which lie outside my retirement accounts. I expect to add to this collection of stocks, improve it, and hope to watch it grow in value over the years. With hard work and good fortune, it may happen.

But there are limits to my ability to apply Buffett's teachings. Where he might see great danger, I might see little risk as a result of not seeing as clearly, or reaching too far. This isn't a warning not to buy stocks, or learn about investing, but I'm not crossing without a net.

Have a great day.

Richard McCaffery doesn't own any shares mentioned in this report. The Motley Fool is investors writing for investors.