The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.By Marc Chandler NEW YORK ( BBH FX Strategy) -- In yesterday's lecture, Federal Reserve chairman rejected the idea that a return to a gold standard is desirable or practical. His pointed remarks come as Republican presidential candidate Ron Paul has fanned ideas in some quarters of the benefits of the discipline of a gold standard. Previously the outgoing World Bank head Robert Zoellick had also advocated a return to a gold standard. In addition, there have been press reports suggesting that some central banks have recently stepped up their purchases of gold for monetary (reserve) purposes. Bernanke's objections were essentially four-fold. First, a gold standard prevents adjusting policy in response to shifting economic conditions. No matter how high unemployment rose, for example, under the strict adherence to a gold standard, monetary policy tools could not be used. Second, by participating in a gold standard, countries would be more vulnerable to developments in other countries. It would increase the transmission mechanism, leaving countries more sensitive to developments of other participants. Third, Bernanke cited the challenge of credibility. Participants have to convince investors that they will sacrifice all domestic goals for the sake of maintaining the gold standard. This seems hardly politically feasible under representative governments. If there is any doubt whatsoever, there would be speculative attacks. Bernanke noted that the gold standard did not prevent frequent financial crises/panics. Fourth, Bernanke acknowledged that a gold standard did promote price stability over the very long run. However, he noted that over the medium run, it sometimes caused periods of inflation and deflation. He cited the second half of the 19th century when a shortage of gold reduced U.S. money supply and fueled deflation. Bernanke warned that the gold standard often produced pro-cyclical impulses. During periods of strong growth, money supply would increase and interest rates would fall, which is exactly the opposite of modern central banking and the withdrawal of the proverbial punchbowl just as the party gets going. Bernanke cited practical difficulties as well. Essentially he argued there is simply not enough gold. Consider that at the end of last week, the press reported that several central banks had taken advantage of the drop in price to step up their gold purchases. Some 4 tons to 6 tons of gold were said to have been purchased (through the BIS). The "street value" is around $250 million-$300 million. This is a mere pittance by nearly any metric.