1. Intuitively I can accept that in a close society, Government deficits really does not matter, it takes from one pocket and put it into another. As long as society as a whole can balance its book everything should come out OK - a zero sum. It is even positive if the country/society runs a surplus with others.
I am not a trained economist, just an avid reader frustrated with classical economics which is quite contradictory with the real world economics.
MMT says govt. deficit does not matter with the caveat it is constrained by inflation. As long as there is productivity is there to meet the growing demand without increasing inflation, govt. should run deficit.
You are also quoting balancing book loosely. Govt. does not have to balance books, they can create money with key stroke. Contrary to the belief surplus has not been good for the economy. Every time govt. ran surplus recession followed.
2. What if the society/country runs a deficit with the rest of the world? This is the situation with the US. Same outcome as #1?
Are you talking about trade imbalance with rest of the world. There is a relationship between budget deficit and trade imbalance, but is one is to one. In one old paper said trade imbalance effects are about 30% to the deficit, not sure about recent relationship.
3. Where are the limitations, i.e., as some engineers would say, in the limit what gives? If the Government prints 2x, 4x, 8x... eventually what happen? Is it self correcting or a run away feed back loop?
As i said limitation is the increase in inflation itself. One can also look at historical deficit in terms of GDP. In 80's economists were saying 5% was the limit, beyond that rates will shoot up. We blew though that with no effect so far.