凯·尼尔森是当代英美学界著名的分析马克思主义者学者，也是一位社会主义者。在尼尔森看来，马克思主义的平等观念是科学性和规范性的统一，他既以马克思主义平等观的科学性批判西方自由主义规范性理论，也在扬弃西方自由主义规范性理论资源的过程中丰富和发展马克思主义的平等规范性，最终这些都具体落实为一种更优越的社会主义平等理论，以及一种更具道德合理性的社会主义平等社会的实现。尼尔森的马克思主义平等观形成的逻辑理路大致可以概括为“挑战—反驳—回应—构建”的过程。上世纪70年代，马克思主义平等观面临着内外“双向挑战”：一方面有来自马克思主义理论外部的自由主义挑战，另一方面还有来自马克思主义理论内部的非道德主义挑战。相应地，尼尔森对马克思主义平等观的捍卫也是“双重任务”：一方面，尼尔森回应和反驳了来自内外部的挑战，既对罗尔斯和诺齐克的自由主义进行了批判，也在捍卫马克思主义道德规范性，以及反驳米勒和伍德的非道德主义和非平等主义的同时，确立了科学性和规范性统一的马克思主义平等规范性。另一方面，尼尔森还建构了一种既建立在马克思主义科学性基础之上又具有丰富内涵的马克思主义的平等规范性理论，即社会主义平等理论，具体回答了我们应该追求“什么平等”以及“多少平等”的问题。社会主义平等是一种目标，它既是对“平等的有效自由”和“平等的需求满足”之类“目的平等”的追求，也是对“条件平等”和“机会平等”之类“手段平等”的追求；同时，社会主义平等也是一种原则，它既以激进平等主义为基本原则，也纳入了资格和应得等非平等主义原则。此外，社会主义平等既是理论也是现实，它将在现实社会中实现为一种市场社会主义和全球正义。追求一种具有规范导向的马克思主义解放社会科学，是尼尔森的毕生所求和理论旨归。批判性广义反思平衡方法则是尼尔森进行马克思主义规范性论证的基本方法。尼尔森通过将平等规范性根植于历史唯物主义科学性的方式，捍卫和发展了马克思主义的平等规范性，并为我们提供了科学性与规范性统一的研究范式和可能性路径。虽然尼尔森的理论具有激进的乌托邦性质，但依然构成一种启发式的理想，为当前社会主义平等理论和实践提供了重要的理论资源。
Kai Nielsen is a famous analytical Marxist scholar and socialist among contemporary Anglo-American academics. For Nielsen, the Marxist conception of equality is a unity of scientificity and normativity, and he both critiques the Western liberal normative theory of equality in terms of the scientific nature of the Marxist conception of equality, and enriches and develops the Marxist normative theory of equality in the process of discarding Western liberal normative theoretical resources. Ultimately, these materialize into a superior socialist theory of equality, and the realization of a more morally justifiable socialist egalitarian society. The logic of Nielsen’s Marxist view of equality can be summarized as a process of “challenge-refutation- responsion-development”. In the 1970s, the Marxist concept of equality faced internal and external “two-way challenges”: on the one hand, there were liberal challenges from outside Marxist theory, with Rawls’ liberal egalitarian theory based on the principle of difference being regarded as the most adequate theory of equality, and Nozick’s denial of equality on the basis of full capitalist property rights; on the other hand, there are immoralism challenges from within Marxist theory, who not only question the moral normativity of Marxism as a whole, but also make specific denials of the Marxist normative concept of equality. Further, Nielsen’s defense of the Marxist concept of equality is naturally a “double task”: on the one hand, Nielsen responds and refutes challenges from within and without, both by critiquing the liberals of Rawls and Nozick, and by establishing a unified scientific and normative Marxist normativity of equality while defending Marxist moral normativity and refuting Miller’ and Wood’s immoralism and non-egalitarianism; on the other hand, Nielsen also constructs a Marxist normative theory of equality that is based on the scientific foundation of Marxism and has rich connotations, namely, the socialist theory of equality, which specifically answers the questions of “equality of what” and “how much equality” we should pursue. Socialist equality is a kind of goal, which is not only the pursuit of “equality of purpose” such as “equal effective freedom” and “equal satisfaction of needs”, but also the pursuit of “equality of means” such as “equality of conditions” and “equality of opportunity”; at the same time, socialist equality is also a principle that takes radical egalitarianism as its basic principle, but it also incorporates non-egalitarian principles such as entitlement and desert.Moreover, socialist equality is both a theory and a reality, and it will be realized in the real world as a form of market socialism and global justice.The pursuit of a normatively oriented Marxist social science of emancipation has been Nielsen’s lifelong quest and theoretical aspiration. The Critical Wide Reflective Equilibrium approach is Nielsen’s basic method for making Marxist normative arguments. By rooting egalitarian normativity in historical materialist science, Nielsen defends and develops the egalitarian normativity of Marxism, and provides us with a research paradigm and a path of possibilities for the unification of science and normativity. Despite its radical utopian nature, Nielsen’s theory still constitutes a heuristic ideal that provides an important theoretical resource for current socialist equality theory and practice.
