Donald Trump's surge to the lead in Republican presidential polls has his competitors flummoxed. They would do better to offer positive ideas rather than complaints about the billionaire real estate mogul, says Steve Forbes, publisher of Forbes Media.

"These veterans of the public square violated the first law of politics: they let Trump set the agenda," Forbes writes on Forbes.com. "To be heard, you have to have something to say, and Trump has plenty to say." The Donald, of course, has focused on immigration and relations with Mexico and China.

So what should the other candidates do? "Simple. Do what Ronald Reagan did in 1980 and establish a substantive pro-growth agenda," Forbes says. "They must lead with their ideas, just like the Gipper did."

For example, Forbes is intrigued with Rand Paul's flat tax proposal, but disappointed the Kentucky senator didn't focus on it during last month's debate.

"Candidates should remember that if they expect to have any hope of displacing The Donald, they can’t be passive or vague about what they stand for," Forbes states.

Elsewhere on the economic front, some notable economists argue that technological innovations in the future won't raise our living standards as much as they have in the past, dooming the economy to slow growth.

But Harvard economist Martin Feldstein begs to differ.

While GDP growth per worker has shrunk markedly since 1972, "the official statistics on GDP growth fail to capture most of the gains in our standard of living that come from new and improved goods and services," he writes on Project Syndicate. So the depressed numbers don't account for air conditioning, new surgical procedures etc.

The economy has grown only 2.1 percent a year since the Great Recession ended in June 2009, compared to a rate of 3 percent from 1960 to now. But that doesn't mean we're doomed to poverty, Feldstein says.

"There is simply no reason for the view . . . that the children of today will not enjoy a standard of living as high as their parents’." To guarantee a bright future, we need to improve education, boost savings and investment and reform taxes and entitlements, Feldstein says.

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