On his blog (yes, Ben Bernanke has a blog), the former Federal Reserve Chairman wrote that he was “appalled” by U.S. Treasury Secretary Jack Lew’s decision to “demote” Hamilton from the $10 bill, in order to replace him with a still-unnamed woman by 2020.

Like many others — including Fortune‘s Christopher Matthews — Bernanke feels that Hamilton, America’s first Treasury Secretary, earned his spot on U.S. currency, due to his foundational contributions to the U.S. economy:

Critically, he helped put U.S. government finances on a sound footing, consolidating the debts of the states and setting up a strong federal fiscal system. The importance of Hamilton’s achievement can be judged by the problems that the combination of uncoordinated national fiscal policies and a single currency has caused the Eurozone in recent years.

Hamilton also played a leading role in creating U.S. monetary and financial institutions. He founded the nation’s first major bank, the Bank of New York; and, as Chernow points out, Hamilton’s 1791 Report on the Mint set the basis for U.S. currency arrangements, which makes his demotion from the ten dollar bill all the more ironic. Importantly, over the objections of Thomas Jefferson and James Madison, Hamilton also oversaw the chartering in 1791 of the First Bank of the United States, which was to serve as a central bank and would be a precursor of the Federal Reserve System.

This isn’t to say, however, that Bernanke is opposed to the idea of adding a woman to U.S. paper money. It’s just that he thinks Andrew Jackson should be demoted from the $20 bill, rather than Hamilton from the $10.