I had the good fortune to welcome a new follower on Twitter last week. Todd Tresidder is a financial coach who, by the time he was 35, had made enough to retire from the hedge fund industry a wealthy man. Today he’s a successful investor and financial coach in Reno, Nevada.

Tresidder seemed a perfect guest to talk with about what lies ahead for the U.S. economy. He didn’t bite. “Forecasts are meaningless,” he reminded me.

Tresidder teaches that sound investment strategies are built on knowledge, not predictions. “What I’m looking for is truths,” he said. “If you want to be rational and intelligent about your approach, you have to get really clear on what’s known, what’s knowable and what’s forever unknowable. The forecast – or future – is forever unknowable.”

This is a guy worth listening to. So we talked about the fundamentals. I took five lessons away:

1. Even safe predictions are useless. I pressed Tresidder on his contention that forecasts do no good. Aren’t there certain safe predictions that are worth factoring into an investment decision? “No because the reality is that the knowledge is widespread and fully priced into the system,” he said. “So from an investor’s standpoint, [the prediction] has no relevance.”

2. Investing is boring. “I teach clients that investing done right is about as exciting as watching paint dry,” he said. “The creativity and the intelligence behind your investing are not in the choice of the investment but rather in the disciplined approach that’s behind your investment strategy. The actual process of investing is an administrative function.”

3. Different investment strategies work for different people at different times. Take a buy-and-hold strategy for example, which has a ton of research supporting it. But timing and valuations matter. “Buy and hold can be the world’s smartest strategy at some times and it can be a really poor risk-reward bet at other times,” he said. “Some clients use long-term risk management tools that I teach. Some use a value-based approach. Some use conventional asset allocation. Some clients use real estate. And other clients I have use a dividend-based model because they’re looking for cash flow and inflation protection from their stock portfolio. So it really varies with the client.”

4. Given this complexity, professional advice adds value. “I’ve been at this my whole life,” said Tresidder. “Investment strategy isn’t brain surgery, it’s far more complex than that. Brain surgery is a science, whereas investing is a mix of science and human emotions.”

5. Investors overreact. Tresidder has watched his clients and other investors fall victim to market swings again and again. In the 1990s, he spent his time teaching clients that stocks – at that time technology stocks in particular – could be vastly overvalued. By the mid-point of the following decade, real estate was the thing. He had so many clients looking at questionable real estate deals that he liquidated his portfolio in 2006. What’s driving markets now? “Fear and disbelief,” he told me. “People are very fearful. People are very much retrenching.” When will things turn around? That’s not knowable.

One additional observation: Today’s capital markets don’t make sense. “It’s a conundrum to me,” said Tresidder. “Right now, market valuations are above average historically … You’ve got clear fear in the public. You’ve got wide understanding of the issues. You’ve got the media all over it. And yet you’ve still got market valuations that are overinflated. You’ve got interest rates at historic lows. So you’ve got this real mixed bag of numbers and a lot of contradictions.”

Not a bad reason to freshen up on the five rules.