I have a friend who is essentially communist, we debate all sorts of things and he generally agrees we need to get rid of capitalism. However he is assured that there is no way to determine the value of commodities as effectively as the market can through supply and demand (aside from his argument that soon an AI super-intelligence can save us without the market incentives). I try to point out that the market as it is isn't efficient and creates massive waste, pointing to various ways that our system generates waste due to capitalism, and he agrees it is extremely inefficient but still the best we can do right now.
I have read a lot more theory about resistance to capitalism, insurgency, organization and the like but not as much about the specific economics of a communist society once we move past capitalism. Where would be a good place to start? Should I just quote Das Kapital to him?
Even if we accept his argument that it's too complex for humans and need computers to manage it, I'll point to Wall Street high-speed trading software that already runs the economy by this logic. It means we should seize Wall Street and direct those machines towards a different outcome.
Besides, we don't need super-intelligent AI, just computing resources. It's computationally feasible to turn the economy into a big sheet of equations that need balancing. If you squint it's a bunch of Linear Algebra. Like a chess AI, the question becomes how long do you give the computer to calculate a more fine-grained production balance. Finally, we can fudge all of this with buffers (storage tanks, grain silos, warehouses, etc) that can store these materials to absorb inaccuracies in the planning or simply to prepare when plans need changing, like a natural disaster. Paul Cockshott and Allin F. Cottrell's Toward a New Socialism details such a program.