1. Defining the Concept‘Equality’ i

1. Defining the Concept
‘Equality’ is a contested concept: “People who praise it or disparage it disagree about what they are praising or disparaging” (Dworkin 2000, p. 2). Our first task is therefore to provide a clear definition of equality in the face of widespread misconceptions about its meaning as a political idea.
The terms “equality” (Gr. isotes, Lat. aequitas, aequalitas, Fr. égalité, Ger. Gleichheit), “equal,” and “equally” signify a qualitative relationship. ‘Equality’ (or ‘equal’) signifies correspondence between a group of different objects, persons, processes or circumstances that have the same qualities in at least one respect, but not all respects, i.e., regarding one specific feature, with differences in other features. ‘Equality’ needs to thus be distinguished from ‘identity’ — this concept signifying that one and the same object corresponds to itself in all its features: an object that can be referred to through various individual terms, proper names, or descriptions. For the same reason, it needs to be distinguished from ‘similarity’ — the concept of merely approximate correspondence (Dann 1975, p. 997; Menne 1962, p. 44 ff.; Westen 1990, pp. 39, 120). Thus, to say e.g. that men are equal is not to say that they are identical. Equality implies similarity rather than ‘sameness.’
In distinction to numerical identity, a judgment of equality presumes a difference between the things being compared. According to this definition, the notion of ‘complete’ or ‘absolute’ equality is self-contradictory. Two non-identical objects are never completely equal; they are different at least in their spatiotemporal location. If things do not differ they should not be called ‘equal,’ but rather, more precisely, ‘identical,’ as e.g., the morning and evening star. Here usage might vary. Some authors do consider absolute qualitative equality admissible as a borderline concept (Tugendhat & Wolf 1983, p. 170).
‘Equality’ can be used in the very same sense both to describe and prescribe, as with “thin”: “you are thin” and “you are too thin.” The approach taken to defining the standard of comparison for both descriptive and prescriptive assertions of the concept of equality is very important (Oppenheim 1970). In the case of descriptive use of equality, the common standard is itself descriptive, e.g. two people weigh the same. A prescriptive use of equality is present when a prescriptive standard is applied, i.e., a norm or rule, e.g. people ought to be equal before the law. The standards grounding prescriptive assertions of equality contain at least two components. On the one hand, there is a descriptive component, since the assertions need to contain descriptive criteria, in order to identify those people to which the rule or norm applies. The question of this identification — who belongs to which category? — may itself be normative, e.g. to whom do the U.S. laws apply? On the other hand, the comparative standards contain something normative — a moral or legal rule, in the example, the U.S. laws — specifying how those falling under the norm are to be treated. Such a rule constitutes the prescriptive component (Westen 1990, chap. 3). Sociological and economic analyses of (in-)equality mainly pose the questions of how inequalities can be determined and measured and what their causes and effects are. In contrast, social and political philosophy is in general concerned mainly with the following questions: what kind of equality, if any, should be offered, and to whom and when? Such is the case in this article as well.
‘Equality’ and ‘equal’ are incomplete predicates that necessarily generate one question: equal in what respect? (Rae 1981, p. 132 f.) Equality essentially consists of a tripartite relation between two (or several) objects or persons and one (or several) qualities. Two objects a and b are equal in a certain respect if, in that respect, they fall under the same general terminus. ‘Equality’ denotes the relation between the objects that are compared. Every comparison presumes a tertium comparationis, a concrete attribute defining the respect in which the equality applies — equality thus referring to a common sharing of this comparison-determining attribute. This relevant comparative standard represents a ‘variable’ (or ‘index’) of the concept of equality that needs to be specified in each particular case (Westen 1990, p. 10); differing conceptions of equality here emerge from one or another descriptive or normative moral standard. There is another source of diversity as well: As Temkin (1986, 1993) argues, various different standards might be used to measure inequality, with the respect in which people are compared remaining constant. The difference between a general concept and different specific conceptions (Rawls 1971, p. 21 f.) of equality may explain why according to various authors producing ‘equality’ has no unified meaning — or even is devoid of meaning. (Rae 1981, p. 127 f., 132 f.)
For this reason, it helps to think of the idea of equality or for that matter inequality, understood as an issue of social justice, not as a single principle, but as a complex group of principles forming the basic core of today's egalitarianism. Depending on which procedural principle one adopts, contrary answers are forthcoming. Both equality and inequality are complex and multifaceted concepts (Temkin 1993, chap. 2). In any real historical context, it is clear that no single notion of equality can sweep the field. (Rae 1981, p. 132) Many egalitarians concede that much of our discussion of the concept is vague and theoretical. But they believe that there is also a common underlying strain of important moral concerns implicit in it (Williams 1973). Above all it serves to remind us of our common humanity, despite various differences (cf. 2.3. below). In this sense, egalitarians tend to think of egalitarianism as a single coherent normative doctrine — but one in any case embracing a variety of principles. Following the introduction of different principles and theories of equality, I will return in the last section of this article to the question how best to define egalitarianism and the value of equality.