MMT does not depend on or imply the relation between debt and inflation, it addresses the metaphysics of "government debt" as such. In fact it suggests you should not "inflate away the debt", as if governments were subject to an actual fiscal constraint of spending = taxes + borrowing (the premise MMT rejects).
Under MMT, you can inflate away other debts (mortages, student debts, etc.) To do so, it separates taxes from spending. It does away with borrowing to simply create money out of thin air, and return any money collected the same way. Any difference between spending and taxation increases the money supply, causing inflation.
That lets you tune the inflation rate more directly than the Fed's rather distant lever arm. The Fed has been trying to increase inflation, but doing so mostly by pumping it into the financial sector, in the hopes it would trickle down. It hasn't. So all of the inflation is confined to the financial sector, in the form of the stock market (and a few other investments, these days including crypto).
Under MMT you could give the same cash directly to people as stimulus checks or UBI, and know that it will go around at least once or twice before ending up in the financials. Then you can control inflation with taxation, removing as much money as you need to, and simply burning it.
The public debt doesn't matter. Inflation gradually eats away at private debt -- assuming it's distributed properly, which it may not be.
It's flexible and elegant. Whether it actually works is less clear, but its roots are a lot like conventional economic theory. In theory, theory and practice are the same...
> Under MMT, you can inflate away other debts (mortages, student debts, etc.) To do so, it separates taxes from spending.
Taxes are separated from spending, that's just an observable fact
MMT poses a (actually, quite conventional) explanation of the constraints that actually apply to that. It also tends to be adhered to by people with particular policy preferences, but that's not really all that tightly tied to the descriptive elements of the theory. (Though most argument against “MMT” is actually against the policy preferences, not the theory itself.)@
> It does away with borrowing to simply create money out of thin air, and return any money collected the same way.
Well, it doesn't do away with it so much as point out that it is an act of artifice. You can borrow or not, MMT doesn't care: government created money when it runs a deficit and destroys it when it runs a surplus, and reallocated it all the time. All borrowing does is preprogram in an allocation of certain spending in the future, it doesn't change the monetary effects of current “fiscal” balance. (“fiscal” in quotes because the central tenet of MMT is that the metaphor of the “fisc”, the finite government purse, is inapt for modern government finances denominated in fiat controlled by the government involved.)
