NEW YORK ( TheStreet) -- It's nice to see the stock market doing so well lately, but the reasons underlying the recent move upwards concern me.It's deja vu all over again. Investors are waltzing past troubling news that is piling up about the fundamentals of the economy and corporate earnings, and once again they're focused on the punch bowl --the Federal Reserve's revived efforts to pump cheap liquidity into the market and stimulate the economy. Now, some critics are reacting strongly and harshly to the news that Federal Reserve Chairman Ben Bernanke is embarking on a new round of asset purchases to push down interest rates and spur borrowing and risk-taking activity. I admire their strong convictions, but I don't share them. Bernanke is in a difficult jam, and I don't have the expertise to second-guess him. However, I do have two convictions that could be helpful to people as they try to preserve their own wealth and make intelligent decisions about how to manage their investments. First, when investors are pushing up asset prices based on monetary action the Federal Reserve is taking, that's a terrible reason to make a long-term investment in the health of the U.S. economy. The market's focus on the punch bowl is a sign of economic weakness, not strength. Investing in monetary stimulus can work very well for a while -- until it doesn't. Remember the aggressive actions taken by Bernanke's predecessor, Alan Greenspan, in the wake of the Nasdaq collapse and the terrorist attacks of 2001? That was unprecedented at the time. He pushed the Fed's target for short-term interest rates down to record-low levels. Financial markets responded positively, and the economy grew. But in retrospect it's obvious to everyone that the Fed's action was a key ingredient in what became a massive speculative bubble that eventually led to the mother of all financial crises. Of course, that was all child's play compared with the extraordinary monetary actions taken by Bernanke in the aftermath of the financial crisis of 2008, a crisis that is still inflicting insidious economic pains throughout the global economy. The Fed's rate target has been at zero for years now, and the central bank has been buying mortgage bonds in the marketplace to inject more liquidity, a practice that has been creepily dubbed "quantitative easing."