Noted economist and author Robert Shiller, who famously published the book "Irrational Exuberance" near the then-15-year top of the Nasdaq Composite Index, 5132.52, marked in February of 2000. By August 2002, the Nasdaq had plunged as low as 1108.49, a stunning 78 percent tumble in just over two years. It wasn't until 2015 that that the index was able to retake the high, over 15 years later. The American Nobel Laureate also "spotted housing-market excesses," that led to the Great Recession.

Speaking to Bloomberg, comparing the dot-com era with the current one, Mr.

Shiller expressed they are both "revolutionary eras." Eras where accepted securities analysis standards are replaced with new paradigms, and "traditional gauges of equity-market value" are rendered "obsolete." The internet was the dot-com game changer. This time around, it's President Donald Trump.

Shiller observes 'everything is different' sentiment

Robert Shiller described Trump as a "Great Leader"-type figure, who makes people believe, this time "everything is different." The economist holds up the president's promise of growth, and his pro-business agenda against the reality that his brashness creates "uncertainty," something that "investors are supposed to hate most." Both the Dow Jones Industrial Average and the Nasdaq are up over 10 percent since Donald Trump was elected.

How long can the rally continue? Blasting News reported earlier today on the 20-plus percent run by Apple Inc.'s AAPL stock over the past six months. While AAPL shares have remained firm, YY stock, issued by Chinese social-networking firm, YY Inc., bolted higher on strong earnings in this morning's pre-market trading session, only to reverse and trade lower through the day.

Given the "uncertainty," which is something that is generally associated with volatility, Stanford University's Nicholas Bloom stated that it's "hard to say why stock markets are so un-volatile right now." The Volatility S&P 500 Index, the VIX, has traded down over 30 percent since Trump was elected, joined by tightening credit spreads, each metrics purportedly pointing to investor anxiety abating.

How long can Trump stock market rally continue?

Ethan Harris, with Bank of America Merrill Lynch, has observed that markets have entered a period where traders have almost become accustomed to regular shocks. He cited the Brexit vote, the European debt crisis, and the debt-ceiling debate in the United States, with the backdrop of a U.S. economy still not ten year's removed from the depths of the Great Recession. The economist stated that uncertainty has become the "new norm," and observed that investors have become "toughened" by it.

Robert Shiller is humble, "loathe to make short-term" forecasts, and is unwilling to offer any opinion on the short-term direction of the Stock Market. He does offer that the "S&P 500’s cyclically-adjusted price-earnings ratio" sits close to where it sat "on the eve of the 1929 crash." The measure still sits 30 percent below its 2000 peak, which may suggest that the Trump rally can continue. It would seem that Robert Shiller would contend that it can't continue forever.