Rule of JUSTICE

Perelman and Olbrechts-Tyteca introduce the rule of justice as a fundamental argumentative principle: “All beings of the same category must be treated the same.”
This rule governs the distribution of benefits: “To each according to his merit, his birth, his merits” (Perelman [1963], p. 26).

This rule underlies claims such as “equal pay for equal work.” It involves the following operations:

(1) A categorization — First, individuals are categorized as members of a general category, “to be born”; “to have needs”; “to have merit” (acknowledging that one can deserve a punishment and that having demerit is having negative merit); “to be an employee, who has worked such-and-such hours and produced such-and-such valuable products.”
General rights and duties can be defined with reference to this first level; “All human beings have the same right to life.” The following practice refers to a strict a pari argument, classifying thieves as a non-hierarchical category: “A thief is a thief”.

General Baclay was quite the character–a funny woman, very just in her own way. She shot women and men alike–all thieves–whether they stole a needle or an ox. A thief is a thief and they were all shot. It was just.
Ahmadou Kourouma, Allah is not obligated. 2000.[1]

(2) An equality relation and a hierarchy — Second, there is an equality relation defined as “equality of birth, needs, merits, work.”
A hierarchy of individuals is derived from this relationship: “P has worked as much as Q or R…; more than A or B…; less than X or Y…”.

Such equipped categories can be represented on oriented scales. The position of an individual on this scale can be discussed: “Does X have more/less merit than Y?”
This metric is easy to define in cases of work. For example, it can be determined by the weight of the fruit picked from the trees. However, things become more complicated when it comes to scientific production, or when it comes to needs and merits. In any case, criteria must be established to prioritize to one person over another.

(3) A corresponding allocation scale — Another ranking method must be established in order to define the parallel scales of sanctions and rewards. For example, what is the appropriate wage for that level of work?.
Then, the two scales must be coupled.

These two independent valuations ((2) and (3)) make the rule of justice more complex than an a pari argument. An a pari argument holds that “work must pay.” If P works, then P has a right to be paid for that work (unless P is a volunteer working for a nonprofit organization. The rule of justice connects two graduated scales.

Furthermore, it is assumed that the rule of justice is applied to all group members in a linear order. Actual rules include thresholds. For example, with respect to the level of taxation, the rule “to each according to his or her income” applies only above a certain threshold, and incorporates tax brackets and smoothing principles.

Other categories can be considered, showing that the rule of justice can be used to justify injustice:

To each according to their sex.
To each according to their color.

The rule of justice excludes arbitrariness, but not injustice. According to the principle of “favor disfavor”, the rule of justice, necessarily creates innumerable injustices. When the benefits are distributed according to merit, they are not distributed according to birth or need.
The rule of justice is said to be “just” because it excludes the arbitrariness of the principle “to each according to my convenience”; and because the categories with their corresponding hierarchy and the allocation scale have been defined by disregarding the cases to be judged. Thus, “the decision is just because the rule existed before your case. This “justice” is formally just because it allows the application of the legal syllogism.

[1] Ahmadou Kourouma, Allah n’est pas obligé. Paris: Le Seuil, p. 111.