My point being that I was interested in your assertion that you only deal in facts, when MMT is a theory that is based on Keynesianism.
MMT is as much a 'theory' as is Einstein's Theory of Relativity, Darwin's Theory of evolution or Newton's Theory of Gravity, or even Galileo's 'theory' that the earth circles the sun. I can't see you seriously questioning those theories (though I am aware that in the field of science some may have been tweaked over time).
Theory is a difficult word because it has two meanings. In the scientific world it is a proposal which is based on empirical evidence and which has yet to be disproved. The scientific method being to set up experiments/ research to disprove the proposed 'theory'. if it can't be disproved it can be accepted as fact based.
The popular perception of a 'theory' is quite different. It tends to view a theory as something merely speculative with little, apart from the proposer's opinion, to prove it.
The 'Theory' of MMT falls into the first category. It is nothing more than an explanation of how the monetary system of a country with its own sovereign currency actually works. It is entirely evidence based. It is based on the fact that all a country's money is (apart from foreign earnings) issued by the state. Heads of state have issued money for hundreds of years, it's not exactly a new concept. The new concept, introduced permanently in the early 1970s was that the currency 'value' is no longer based on the state's holdings of gold and silver. There is no Gold Standard.
'Money' is now fiat currency based on nothing but trust and the fact that it is the only money accepted by the government for payment of tax and the only money that can be used legally for monetary transactions in the country. The government is able to issue as much of it as it likes (fiat means 'let it be') and it issues it mostly by spending into the economy via its central bank. In our case, the Bank of England. This is a basic and incontrovertible fact.
Of course, the government is constrained by a number of factors when it comes to issuing money, but MMT itself states the basic principle. Can it be disproved?
Banks are able to issue new money in the form of loans under licence from the government, subject to regulation. But although the money that banks issue promotes economic activity they do not add permanently to the county's stock of money because loans are repaid in their entirety (thus destroying the money) and the interest paid on the loan (which is usually more than the rate of inflation) actually tends to remove money from the economy as the profits it generates go in dividends and bonuses to the already wealthy who have a 'marginal propensity to spend' and are more like to save it, thus taking it out of circulation in the economy.
The secondary principle of MMT is that governments spend first and tax to recover some of the money they issued. Not recovering the money would lead to inflation and even hyperinflation. As in those exemplars loved by MMT critics who focus on the issuance of money and ignore the taxation principle, Weimar, Venezuela and Zimbabwe.
A corollary of MMT is that without a government running a deficit the country's money supply for active economic activity diminishes. This is because some money is lost by spending abroad or purchasing foreign goods and some becomes inactive when saved. A government that insists that outgoings must equal incomings (misnamed 'balancing the books') will never be able to expand the money supply enough to accommodate an increase in population or growth in new products and services. A government which runs a surplus, more coming in than going out, will create a shortage of money to drive economic activity. The UK has rarely run a surplus in hundreds of years.
MMT is politically neutral. It can be used by a government of any political colour. It tends to be more favoured by people of 'the left' because it offers ways to support a more equable distribution of resources but it could equally be used to channel money to the already wealthy. In fact, it was during covid when huge amounts of specially created money was poured into dodgy PPE procured for inflated sums by friends and associates of the tories.
What I’m really interested in is how the way the EU operates, fits in with MMT.
The ECB creates and issues the euro for all EU countries which use it. Which means that the individual countries within the eurozone have less control over the amounts of money they might wish to spend and the economic policies they might want to implement. They are constrained by the economic policies of the directors of the ECB.
So, in the case of Greece, which wanted to spend its way out of a recession (Keynesian) , it was forced to implement 'austerity' (monetarist).
If we ever rejoin the EU we should never adopt the euro. Monetary sovereignty is one 'sovereignty' that should never be surrendered.