Tax credits are only good if one pays taxes,

I very clearly said “refundable” tax credit. There is nothing at all regressive about my approach. It taxes the UBI of rich people at the highest rate and the UBI of poor people not at all, giving them the money if they are in the zero bracket.

Giving everyone tax-free cash payments with no corresponding productivity increase is the simplest recipe for inflation

My point is that the productivity increase has already occurred, but we lack the distributive technology to give people access to it. Productivity does not always have to catch up to demand; sometimes, demand has to catch up to productivity.

and indexing the benefit to inflation to prevent its erosion would only increase inflation and further harm the poor.

I don’t recall suggesting indexing, although that’s not really a bad idea, because the point of the UBI is to enable people to buy things they need. If the price of those things goes up, so, too should the income of those in need. There are other ways to control inflation. Even if the UBI is indexed, a tax increase, or Volckeresque indes rates would squeeze off inflation. The UBI is just Social Security for everybody. If we can’t get enough stuff for dollars, then something will have to give. But I don’t see why the poorest UBI recipients, the ones who need indexing the most, should be the default choice to get a cut in their real income. Isn’t that “regressive”?

UBI also fails another important criterion for transfer payments. It is not countercyclical to the business cycle, so it does nothing to mitigate recessions or preserve supply chains.

I don’t believe the UBI is a “transfer payment.” That’s my argument against paying for it. I think it primarily taps excess capacity. Was damming the Colorado River a transfer payment? It surely enriched real estate owners in the vicinity. But at whose expense? There was a plus-sum opportunity, and it was exploited. Win-win. UBI is just the New Deal, but with the money spent on something other than public works. It’s not a transfer payment unless we raise taxes to pay for it, and I haven’t seen evidence that we need to do that.

The middle class would quickly acclimate to the additional income, making it essential to their lifestyle, which would increase demand for labor initially, but do nothing to prevent or mitigate downturns in the long run.

You mean they would spend more? Isn’t that a good thing for anyone who has anything, including labor, to sell? Why would that be temporary if the UBI is permanent? As with inflation, there are other ways to deal with downturns. Tax cuts, infrastructure spending, and interest rate cuts all remain on the table. The UBI is, as Yang puts it, a dividend we have earned by being a global hegemon. It monetizes and distributes the tribute we get from our trading partners in the form of lower interest rates on our debt. We’ve earned it, and there is no macro reason we shouldn’t declare it and pay it.