Some parts of this paper restate points that Rawls has by now made familiar such as the invocation of the "veil of ignorance" and its connection to the "original position" though he also here adds that the parties in this position are not individuals but, rather, "family heads", a specification presumably meant to show their representative function but which has some implications not here discussed (what of those not in families, do they not have distinguishable interests?).
Similarly Rawls again makes clear his commitment to the notion of the "basic structure" of society and the associated generality of the question being asked in his account of distributive justice. The notion of the "representative man" is again focused particularly on the least favoured income class as was the case in the 1968 paper on distributive justice. The notion of "primary goods" makes an appearance in the paper with the notion of self-respect identified as a particularly pertinent example of such a good.
The examination of the second principle is undertaken with regard to certain possible systems, and this is undertaken by rendering the principle of openness to offices by means of Pareto optimality. By contrast the notion of the mutual advantage garnered from inequalities is termed the "difference principle", the term first used by Rawls in the 1968 paper on distributive justice.
Having distinguished and specified the two parts of the second principle of justice Rawls next relates some interpretations of the principle in question that will produce certain types of social system and assesses the outcome that such systems will produce through the notion of "stability". The first such system examined is that of "natural liberty" in which the part that speaks of openness to offices is understood to mean that equality requires careers open to talents and this is combined with Pareto optimality. This produces, Rawls assumes, roughly a free market system although it does not automatically require that the means of production are privately owned. Pareto optimality is not itself tied to any particular distribution though in the system of natural liberty it is assumed to be best satisfied by a competitive market economy. The "difference principle" is here understood to require only formal equality of opportunity and this ensures that the initial distribution of assets is "strongly influenced by natural and social contingencies". This fact alone is held to count against the system of natural liberty.
By contrast to the system of natural liberty we can invoke the notion of "liberal equality" in which the principle of openness to offices is changed and rendered as equal opportunity "under similar conditions". When we render the notion of openness to offices in this way we arrive, states Rawls, at the principle of fair equality of opportunity. We are not dealing with equal opportunity in a merely formal sense but adding to the view of it that there should be a fair chance to attain opportunities.
So liberal equality seeks to reduce the effect of the natural and social contingencies that were taken to have the decisive weight under a system of merely "natural" liberty. This requires that there are in-built constraints in the social system that seek to prevent excessive concentration of wealth and to maintain equal educational opportunities.
However, whilst Rawls prefers liberal equality to the system of natural liberty he still objects to it on the grounds that the resulting distribution of wealth and income is based primarily on the natural distribution of abilities and talents. This elevates liberal equality into a meritocratic system in opposition to the dependence of the system of natural liberty on historical accidents. However, as Rawls points out, the extent to which natural capacities develop is itself affected by all kinds of social conditions, conditions he generally summarizes as those of the "natural lottery".
This is why the first part of the second principle, the part generally termed the "difference principle" is assumed instead to require that higher expectations of those better situated are treated as just "if and only if" they work as part of a scheme which improves the lot of the least advantaged members of society. This suggestion that all differences in wealth and income should work for the good of the least favoured is what leads to the term "difference principle". It is also taken to work with Pareto optimality in defining a situation that can be seen to be the most efficient one. Rawls terms this condition "democratic equality" by distinction to "liberal equality".
The difference principle is subsequently justified by reference to a number of principles that it is argued to harmonize with. To begin with it is taken to harmonize with the principle of redress or the view that undeserved inequalities require compensation. So the difference principle compensates for the unequal distribution of natural talents and in doing so "the callous aspects of a meritocratic regime are avoided", showing again the importance of the distinction between liberal and democratic equality.
Rawls also suggests that the difference principle connects to the principle of fraternity where this latter is understood to mean "not wanting to have greater advantages unless this is for the benefit of others who are less well off". If understood in this way the revolutionary ideals of liberty, equality and fraternity are all given a place with the first recognised in the first principle of justice, the second specified in terms of fair equality of opportunity and the third in the difference principle. Rawls also suggests a link between the difference principle and the Kantian principle of the kingdom of ends. The difference principle rules out even the view that others should be treated as means to one another's welfare as it will not permit the sacrifice of some to others that naturally emerges as an interpretation of the utilitarian view.
Rawls also takes the difference principle to relate to the principle of reciprocity or mutual benefit and this point then gives the final point to this article which is to show the system of democratic equality is the most stable of those assessed. By stability, Rawls means a system that tends to generate its own support by promoting a sense of justice that corresponds to the social order. The means by which such stability is promoted is by means of public affirmation of the two principles of justice and the way in which they make manifest a form of respect that citizens have for one another as moral persons.
The discussion of stability and its connection to publicity is given far too briefly here and yet the interconnection of the notions seems one of the strongest argumentative suggestions that the essay gives for the superiority of democratic equality over the other systems mentioned. The failure of Rawls to follow this argument further and make it the centre of the article is intriguing and suggests some questions in terms of thinking more about the justification of the difference principle.