But Gates spoke approvingly of a general wealth tax, the estate tax, and changes to Social Security in order to increase tax revenue. “But we can be more progressive, the estate tax and the tax on capital, the way the FICA and Social Security taxes work. We can be more progressive without really threatening income generation.”

Gates also took exception to “modern monetary theory,” which is an economic theory with growing prominence on the policy teams of Ocasio-Cortez, Bernie Sanders, and others. MMT, as it’s known, suggests that governments need not worry about deficits because they can simply print their own currency, and should instead manage inflation with interest rates. (You can read more about it in this Vox explainer.) What does Gates think of MMT?

“That is some crazy talk,” he told me. “It will come back and bite you.”