One of the world's authorities on the design and implementation of currency systems and author of Money and Sustainability, Professor Lietaer has become one of the leading critics of fiat money systems...
I find this surprising. For >30 years, Prof Lietaer has always maintained that currencies need to be backed by something such as a basket of goods. Bitcoin is backed by nothing. I hope he says it again, because it's true.
See https://www.bitcoinwednesday.com/event/bitcoin-wednesday-47/ for the full conference program.