The problem with trying to operate a "planned economy" is, of course, that people form plans from their own knowledge, including specific knowledge of persons, places, tools, and so on -- knowledge of costs and opportunities that cannot be written down on forms, collected in a central office, and processed into a "plan". Economic activities are planned by the people with the knowledge -- that is, by the people, and in a distributed and unpredictable way.

To the limited extend that central planning is possible, it functions as a supplement to these dispersed plans:

• It places some actions out of bounds via law and regulation.

• It changes incentives via taxes and subsidies

• It makes specific things happen via purchase of goods and services.      

• It influences broad levels of activity (via macroeconomic fiddling).

The original, historical "socialist planning" contemplated far more than this. It failed for fundamental reasons rooted in the distributed nature of societal knowledge. (Sweden is in no sense socialist, in the original sense.)

Einstein's thought was directed toward finding simple, universal, all-embracing principles. This was not a good background for contemplating the super-human complexity of society.

Words and ideas I offer here may be used freely and without attribution.