Those of you who read the Comments will have seen an exchange between Chris and myself triggered by my post on Paul Krugman. There was one little phrase in Chris's last comment that raises some interesting questions for anyone trying to imagine a socialist society [something, by the way. that Marx did only fitfully and not in any systematic fashion, for good reason.] In the midst of a wider comment, Chris says that in a socialist society we would want to get rid of surplus value, that being the value form of the labor performed by workers over and above what is required to reproduce their ability to labor. Now, in a socialist society everyone will participate democratically in the important economic decisions of the society, so we cannot deduce a priori what will be decided. But I am pretty sure folks are not going to want to get rid of all of that surplus labor, regardless of whether it is called "surplus value" or not. Let me explain why. This is going to take a while, because there are a great many reasons for not limiting ourselves in a socialist society to necessary labor.
First of all, let us just be clear about what constitutes necessary labor. The total labor required to produce the means of existence of the working class is necessary labor. This includes the labor required to replace the used up means of production [tools, machinery, raw materials, etc.]. Since the workers themselves must be replaced as they "wear out," necessary labor includes the labor that supports the raising of children and the preparation of them to enter the work force [including some, but by no means all, of their education.] All of this is a matter of physical, chemical, and biological laws, and can no more be ignored by a socialist society than it can ignore the times tables.
Why might a socialist society decide that more than this necessary labor ought to be performed? [I.e., why might a socialist society decide to engage in "surplus labor"?] There are many reasons. Here are some of them.
First, a socialist society might decide that it wants to perform enough labor to make it possible for old people, sick people, and others not available for the labor force to live decent lives. This labor is in no way required by the objective dictates of the economy. A socialist society could perfectly well decide to allow its old people to starve and die, denying them even medical care [which requires medical workers to perform surplus labor, of course.] I would certainly hope that a democratic socialist society would make such a choice, but let us be clear: it would be a choice to perform surplus labor, not a requirement for the reproduction of the working class [as the raising of children is.]
Second, a socialist society might decide to alter the definition of "necessary labor" by raising the standard of living of the working class to include entertainment, additional leisure, luxury goods [like IPhones], or education in the Humanities [not really required to prepare the labor force for productive labor, no matter what desperate Philosophy Departments may say these days.] As David Ricardo pointed out half a century before Marx published Capital, what constitutes "subsistence" in a society at any time in its history is in part determined socially, not simply biologically.
Third, as the demographic composition of the population changes [more children, or maybe fewer children and more old folks], a socialist society that has decided to perform the surplus labor required to support those not in the labor force will find the quantity of that surplus labor changing. If the population is aging, as America's is, those in the labor force will have to increase the amount of surplus labor they perform, because [as economists sometimes say] a smaller fraction of the total population will be supporting the entire population with its labor.
Fourth, the population may be growing. [This is different from the demographic mix changing.] A socialist society may decide [but, as always, it need not -- this is a genuine choice] that it wants to expand the Gross Domestic Product at a corresponding rate, so that the average level of consumption need not be reduced. This will require surplus labor from those engaged in producing the stuff needed to expand output [machinery, tools, etc. -- what I would call capital goods, but Chris does not like that word "capital," so I will just call it "stuff."] If the population keeps growing, output will have to keep growing to avoid a decline in living standards.
Fifth [this one is a bit tricky], people in a socialist society may decide that they want to work harder than they need to, in order to expand the amount of stuff available to raise the level of output, so that some future generation [their children, their grand-children] can live better lives than they do. There a number of societies, mostly notably the People's Republic of China, that have made this decision, although in the case of China it would be stretching the meaning of words unacceptably to describe this decision as "democratic."
These are just some of the reasons why the people in a socialist society might decide to perform what is technically classified as surplus labor. Marx knew all of this, of course. Indeed, all of this will occur to anyone who thinks about the matter for a few moments without wearing ideological blinders.
So, Chris, unless you really mean to endorse a heartless, ruthless, take no prisoners, throw-the-old-folks-out-on-the-street form of socialism, I would be a little cautious about saying so readily that you want to get rid of that surplus value. Of course, you can certainly refuse to call it "surplus value," or even "surplus labor," but renaming things, by and large, does not change their nature, as Marx in a number of passages rather mordantly points out.