The gold standard also ties money supply to gold production which is a little like tying fed policy to the quarterly flip of a coin. For example, the Australian and Californian gold rushes of the 1850's caused huge short term price instability.
I'd counter the above statement with the following:
Many problems were solved with our departure from the gold standard and paper money is backed by the faith and credit of the country that prints it and it's value should, and does, fluctuate accordingly.
But arguing with an anonymous "smartest man in Europe" is a little like arguing with Santa.