Ludwig von Mises’s essay “Economic Calculation in the Socialist Commonwealth,” references Aristophanes’ play The Birds and the medieval fantasy of the idyllic and work-free Land of Cockaigne when Mises notes of socialist planners that,
Economics as such figures all too sparsely in the glamorous pictures painted by the Utopians. They invariably explain how, in the cloud-cuckoo lands of their fancy, roast pigeons will in some way fly into the mouths of the comrades, but they omit to show how this miracle is to take place. 
Don Lavoie similarly points to the science fictional/fantastical aspect of socialist planning discussions when he comments in Rivalry and Central Planning that,
Details of future social life are not the province of economic science but of speculative literature. 
Certainly one feels the fantasy novel being written in Michael Albert and Robert Hahnel’s article “Participatory Planning,” as they outline the precisely thought-out details of how their version of socialist planning will function:
Every individual, family, or living unit would belong to a neighborhood consumption council. Each neighborhood council would belong to a federation of neighborhood councils the size of a city ward or rural county. Each ward would belong to a city consumption council, each city and country council would belong to a state council, and each state council would belong to the national consumption councils.
One reason for the nesting of the consumers’ councils is to allow for the fact that different kinds of consumption affect different numbers of people. The color of my underwear concerns only me and my most intimate acquaintances. The shrubbery on my block concerns all who live on the block. …Real national security affects all citizens in a country and protection of the ozone layers affects all humanity––which means that my choice of deodorant, unlike my choice of underwear, concerns more than me and my intimates! 
That is, for those who have lost count, at least five levels of councils, each of which will presumably have regular meetings to manage the work produced for them by the other councils. The socialists are certainly going to be busy. And they would have to be, since something as personal as deodorant will be a matter, apparently, for public discussion by the council. (One wonders, incidentally, how Albert and Hahnel can so callously dismiss the immense importance of choosing unbleached, organic, fair-trade cotton for one’s delicates. But their neighborhood council will presumably deal with this lapse in social responsibility.)
It's Impossible to Remove Human Flaws
The fantasy here is the “Cloudcuckooland” dream that these meetings will be frictionless, will avoid endlessly-offered opportunities for rent-seeking and log-rolling, will not devolve into a rule by those who have the most time to attend meetings, or the greatest facility with language, or simply the loudest and most intimidating voices.
The fantasy is that enough meetings will allow us to overcome human nature. That is why plans like Albert and Hahnel’s are easy to mock. Seeing their many flaws requires no more experience or common sense than one can gain by attending one or two local planning meetings, or PTA gatherings.
"Socialist planning just requires increased ability to do enough calculations fast enough and correctly enough."
Perhaps less transparently problematic is the increasing focus on a different kind of fantasy of how we can make socialist planning really work this time. That is the fantasy of the omniscient computer that automates planning and removes human flaws from the process. It is easy, and I confess, tempting, to mock this as a piece of Star Trek fan fiction gone wild. However, the argument deserves to be taken seriously on its own terms––not just because of its potential technical challenge to classical liberal objections to socialist planning, but also because of its moral challenge.
Allin Cottrell and W. Paul Cockshott pointed out in “Calculation, Complexity, and Planning” that those opposed to central planning have tended to dismiss the argument that in order to work, socialist planning just requires increased ability to do enough calculations fast enough and correctly enough. Now, however,
The "computational argument" is relevant, and…recent advances in computer technology do make possible an effective socialist planning system. 
Rapidly Advancing Artificial Intelligence
Advances in brute computation are increasing at a mind-boggling rate. As Christopher Lee noted in the Washington Post:
The first “petascale” supercomputer will be capable of 1,000 trillion calculations per second. That’s about twice as powerful as today’s dominant model, a basketball-court-size beast known as BlueGene/L at the Energy Department’s Lawrence Livermore National Laboratory in California that performs a peak of 596 trillion calculations per second.
The computing muscle of the new petascale machines will be akin to that of more than 100,000 desktop computers combined, experts say. A computation that would take a lifetime for a home PC and that can be completed in about five hours on today’s supercomputers will be doable in as little as two hours.
So we can do more math, and we can do it faster. But it is particularly the advances made in neural networks where twenty-first-century planners seem to put their faith. These advances have begun to allow computers to better approximate biological brains. They are, very roughly, an attempt to abstract the complexities of biological neural networks and create an artificial version that will allow the computer’s processors to focus on the most important aspects of the given information and to make decisions without needing to “do the math” all the way down.
Learning From the Butterfly
Cottrell and Cockshott point to the way a butterfly presumably assesses costs and benefits when hunting nectar.
It appears that neural networks are capable of producing optimal (or at least highly efficient) behavior, even when faced with exceedingly complex constraints, without reducing the problem to the maximization (or minimization) of a scalar.
That such work can be successfully done by a butterfly for its own purposes, they argue, suggests that it can be done on a large scale by a large computer for general economic purposes. That is to say, if one
wishes to perform global optimizations on the whole economy, other computation techniques, having much in common with the way nervous systems are thought to work, may be more appropriate, and these can in principle be performed without resort to arithmetic.
Good enough technology, in other words, eliminates the need for math, and eliminates the argument that socialist planning is a technical impossibility.
Will Technology Make Utopias Possible?
Arguments like Cottrell and Cockshott’s, it seems to me, present a more important challenge for twenty-first-century classical liberals and libertarians than the easily mocked arguments of old-style planners. As we are often fans of innovation and technological progress, it can be a bit tempting to place a lot of hope in technical solutions. So the question then becomes a dual one. The first is the same as it has always been: Is the technology, as yet, up to the task?
What about that choice would be moral or immoral? Liberating or enslaving? That should be the new focus of the debate.
A random sampling of the scientists I know indicates that so far, it is not. But they were not inclined to dismiss that possibility for the future, given how rapidly our technical capabilities are expanding. That raises the second and much more important question: Even if it were possible for a computer to work as Cottrell and Cockshott’s argument would require it to work, should we use it that way?
What about that choice would be moral or immoral? Liberating or enslaving? That should be the new focus of the old socialist calculation debate.
 Mises, Ludwig von, “Economic Calculation in the Socialist Commonwealth” In Collectivist Economic Planning: Critical Studies on the Possibilities of Socialism, edited by F. A. Hayek, 87-116. London: Routledge, 1947
 Lavoie, Don. Rivalry and Central Planning: The Socialist Calculation Debate Reconsidered. New York: Cambridge University Press, 1985.
 Albert, Michael and Robin Hahnel. “Participatory Planning.” Science and Society 56, no. 1 (Spring 1992): 39-59.
 Cottrell, Allin and W. P. Cockshott. “Calculation, Complexity, and Planning: The Socialist Calculation Debate Once Again.” Review of Political Economy 5, no. 1 (July 1993): 73-112.