Babbitt reported on the 10th, on August 10th, at the "Libra: A Financial Innovation Experiment" new book forum and new book conference, economist Zhu Jiaming said that Libra's greatest contribution is to let us understand its history from a deeper historical perspective. The challenges of classical monetary theory and modern monetary theory. For example: Is the currency neutral? Is there any hallucination in money? Is there an optimal amount of money? These issues have not been discussed clearly, and the emergence of digital currencies has made these problems more complicated. Zhu Jiaming said: "Because of the emergence of bitcoin, Libra and other digital currencies and blockchains, the theory and practice of the currency field will fully enter a new era of more diversification. In theory, the theory of quantity of money, Keynesian theory, two The combination of the two, as well as the new monetary economics, combined with the digital currency theory triggered by digital currency, will coexist. In real money financial activities and economic life, the dual-track system of sovereign currency and non-sovereign currency, physical currency and virtual currency The coexisting 'new copy standard system' will coexist."